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SeminarOpen Source

Introduction to protocols.io: Scientific collaboration through open protocols

Lenny Teytelman
Founder & President of protocols.io
Nov 17, 2025

Research articles and laboratory protocol organization often lack detailed instructions for replicating experiments. protocols.io is an open-access platform where researchers collaboratively create dynamic, interactive, step-by-step protocols that can be executed on mobile devices or the web. Researchers can easily and efficiently share protocols with colleagues, collaborators, the scientific community, or make them public. Real-time communication and interaction keep protocols up to date. Public protocols receive a DOI and enable open communication with authors and researchers to foster efficient experimentation and reproducibility.

SeminarNeuroscience

Astrocytes: From Metabolism to Cognition

Juan P. Bolanos
Professor of Biochemistry and Molecular Biology, University of Salamanca
Oct 2, 2025

Different brain cell types exhibit distinct metabolic signatures that link energy economy to cellular function. Astrocytes and neurons, for instance, diverge dramatically in their reliance on glycolysis versus oxidative phosphorylation, underscoring that metabolic fuel efficiency is not uniform across cell types. A key factor shaping this divergence is the structural organization of the mitochondrial respiratory chain into supercomplexes. Specifically, complexes I (CI) and III (CIII) form a CI–CIII supercomplex, but the degree of this assembly varies by cell type. In neurons, CI is predominantly integrated into supercomplexes, resulting in highly efficient mitochondrial respiration and minimal reactive oxygen species (ROS) generation. Conversely, in astrocytes, a larger fraction of CI remains unassembled, freely existing apart from CIII, leading to reduced respiratory efficiency and elevated mitochondrial ROS production. Despite this apparent inefficiency, astrocytes boast a highly adaptable metabolism capable of responding to diverse stressors. Their looser CI–CIII organization allows for flexible ROS signaling, which activates antioxidant programs via transcription factors like Nrf2. This modular architecture enables astrocytes not only to balance energy production but also to support neuronal health and influence complex organismal behaviors.

SeminarOpen Source

Introduction to protocols.io: Scientific collaboration through open protocols

Lenny Teytelman
Founder & President of protocols.io
Sep 24, 2025

Research articles and laboratory protocol organization often lack detailed instructions for replicating experiments. protocols.io is an open-access platform where researchers collaboratively create dynamic, interactive, step-by-step protocols that can be executed on mobile devices or the web. Researchers can easily and efficiently share protocols with colleagues, collaborators, the scientific community, or make them public. Real-time communication and interaction keep protocols up to date. Public protocols receive a DOI and enable open communication with authors and researchers to foster efficient experimentation and reproducibility.

SeminarNeuroscience

How the presynapse forms and functions”

Volker Haucke
Department of Molecular Pharmacology & Cell Biology, Leibniz Institute, Berlin, Germany
Aug 27, 2025

Nervous system function relies on the polarized architecture of neurons, established by directional transport of pre- and postsynaptic cargoes. While delivery of postsynaptic components depends on the secretory pathway, the identity of the membrane compartment(s) that supply presynaptic active zone (AZ) and synaptic vesicle (SV) proteins is largely unknown. I will discuss our recent advances in our understanding of how key components of the presynaptic machinery for neurotransmitter release are transported and assembled focussing on our studies in genome-engineered human induced pluripotent stem cell-derived neurons. Specifically, I will focus on the composition and cell biological identity of the axonal transport vesicles that shuttle key components of neurotransmission to nascent synapses and on machinery for axonal transport and its control by signaling lipids. Our studies identify a crucial mechanism mediating the delivery of SV and active zone proteins to developing synapses and reveal connections to neurological disorders. In the second part of my talk, I will discuss how exocytosis and endocytosis are coupled to maintain presynaptic membrane homeostasis. I will present unpublished data regarding the role of membrane tension in the coupling of exocytosis and endocytosis at synapses. We have identified an endocytic BAR domain protein that is capable of sensing alterations in membrane tension caused by the exocytotic fusion of SVs to initiate compensatory endocytosis to restore plasma membrane area. Interference with this mechanism results in defects in the coupling of presynaptic exocytosis and SV recycling at human synapses.

SeminarNeuroscience

Neural circuits underlying sleep structure and functions

Antoine Adamantidis
University of Bern
Jun 12, 2025

Sleep is an active state critical for processing emotional memories encoded during waking in both humans and animals. There is a remarkable overlap between the brain structures and circuits active during sleep, particularly rapid eye-movement (REM) sleep, and the those encoding emotions. Accordingly, disruptions in sleep quality or quantity, including REM sleep, are often associated with, and precede the onset of, nearly all affective psychiatric and mood disorders. In this context, a major biomedical challenge is to better understand the underlying mechanisms of the relationship between (REM) sleep and emotion encoding to improve treatments for mental health. This lecture will summarize our investigation of the cellular and circuit mechanisms underlying sleep architecture, sleep oscillations, and local brain dynamics across sleep-wake states using electrophysiological recordings combined with single-cell calcium imaging or optogenetics. The presentation will detail the discovery of a 'somato-dendritic decoupling'in prefrontal cortex pyramidal neurons underlying REM sleep-dependent stabilization of optimal emotional memory traces. This decoupling reflects a tonic inhibition at the somas of pyramidal cells, occurring simultaneously with a selective disinhibition of their dendritic arbors selectively during REM sleep. Recent findings on REM sleep-dependent subcortical inputs and neuromodulation of this decoupling will be discussed in the context of synaptic plasticity and the optimization of emotional responses in the maintenance of mental health.

SeminarNeuroscience

“Development and application of gaze control models for active perception”

Prof. Bert Shi
Professor of Electronic and Computer Engineering at the Hong Kong University of Science and Technology (HKUST)
Jun 11, 2025

Gaze shifts in humans serve to direct high-resolution vision provided by the fovea towards areas in the environment. Gaze can be considered a proxy for attention or indicator of the relative importance of different parts of the environment. In this talk, we discuss the development of generative models of human gaze in response to visual input. We discuss how such models can be learned, both using supervised learning and using implicit feedback as an agent interacts with the environment, the latter being more plausible in biological agents. We also discuss two ways such models can be used. First, they can be used to improve the performance of artificial autonomous systems, in applications such as autonomous navigation. Second, because these models are contingent on the human’s task, goals, and/or state in the context of the environment, observations of gaze can be used to infer information about user intent. This information can be used to improve human-machine and human robot interaction, by making interfaces more anticipative. We discuss example applications in gaze-typing, robotic tele-operation and human-robot interaction.

SeminarNeuroscienceRecording

An inconvenient truth: pathophysiological remodeling of the inner retina in photoreceptor degeneration

Michael Telias
University of Rochester
Apr 7, 2025

Photoreceptor loss is the primary cause behind vision impairment and blindness in diseases such as retinitis pigmentosa and age-related macular degeneration. However, the death of rods and cones allows retinoids to permeate the inner retina, causing retinal ganglion cells to become spontaneously hyperactive, severely reducing the signal-to-noise ratio, and creating interference in the communication between the surviving retina and the brain. Treatments aimed at blocking or reducing hyperactivity improve vision initiated from surviving photoreceptors and could enhance the signal fidelity generated by vision restoration methodologies.

SeminarNeuroscience

Active Predictive Coding and the Primacy of Actions in Natural and Artificial Intelligence

Rajesh Rao
University of Washington
Apr 6, 2025
SeminarNeuroscience

Structural & Functional Neuroplasticity in Children with Hemiplegia

Christos Papadelis
University of Texas at Arlington
Feb 20, 2025

About 30% of children with cerebral palsy have congenital hemiplegia, resulting from periventricular white matter injury, which impairs the use of one hand and disrupts bimanual co-ordination. Congenital hemiplegia has a profound effect on each child's life and, thus, is of great importance to the public health. Changes in brain organization (neuroplasticity) often occur following periventricular white matter injury. These changes vary widely depending on the timing, location, and extent of the injury, as well as the functional system involved. Currently, we have limited knowledge of neuroplasticity in children with congenital hemiplegia. As a result, we provide rehabilitation treatment to these children almost blindly based exclusively on behavioral data. In this talk, I will present recent research evidence of my team on understanding neuroplasticity in children with congenital hemiplegia by using a multimodal neuroimaging approach that combines data from structural and functional neuroimaging methods. I will further present preliminary data regarding functional improvements of upper extremities motor and sensory functions as a result of rehabilitation with a robotic system that involves active participation of the child in a video-game setup. Our research is essential for the development of novel or improved neurological rehabilitation strategies for children with congenital hemiplegia.

SeminarNeuroscience

Vision for perception versus vision for action: dissociable contributions of visual sensory drives from primary visual cortex and superior colliculus neurons to orienting behaviors

Prof. Dr. Ziad M. Hafed
Werner Reichardt Center for Integrative Neuroscience, and Hertie Institute for Clinical Brain Research University of Tübingen
Feb 11, 2025

The primary visual cortex (V1) directly projects to the superior colliculus (SC) and is believed to provide sensory drive for eye movements. Consistent with this, a majority of saccade-related SC neurons also exhibit short-latency, stimulus-driven visual responses, which are additionally feature-tuned. However, direct neurophysiological comparisons of the visual response properties of the two anatomically-connected brain areas are surprisingly lacking, especially with respect to active looking behaviors. I will describe a series of experiments characterizing visual response properties in primate V1 and SC neurons, exploring feature dimensions like visual field location, spatial frequency, orientation, contrast, and luminance polarity. The results suggest a substantial, qualitative reformatting of SC visual responses when compared to V1. For example, SC visual response latencies are actively delayed, independent of individual neuron tuning preferences, as a function of increasing spatial frequency, and this phenomenon is directly correlated with saccadic reaction times. Such “coarse-to-fine” rank ordering of SC visual response latencies as a function of spatial frequency is much weaker in V1, suggesting a dissociation of V1 responses from saccade timing. Consistent with this, when we next explored trial-by-trial correlations of individual neurons’ visual response strengths and visual response latencies with saccadic reaction times, we found that most SC neurons exhibited, on a trial-by-trial basis, stronger and earlier visual responses for faster saccadic reaction times. Moreover, these correlations were substantially higher for visual-motor neurons in the intermediate and deep layers than for more superficial visual-only neurons. No such correlations existed systematically in V1. Thus, visual responses in SC and V1 serve fundamentally different roles in active vision: V1 jumpstarts sensing and image analysis, but SC jumpstarts moving. I will finish by demonstrating, using V1 reversible inactivation, that, despite reformatting of signals from V1 to the brainstem, V1 is still a necessary gateway for visually-driven oculomotor responses to occur, even for the most reflexive of eye movement phenomena. This is a fundamental difference from rodent studies demonstrating clear V1-independent processing in afferent visual pathways bypassing the geniculostriate one, and it demonstrates the importance of multi-species comparisons in the study of oculomotor control.

SeminarNeuroscience

Rett syndrome, MECP2 and therapeutic strategies

Rudolf Jaenisch
Whitehead Institute for Biomedical Research and Department of Biology, MIT, Cambridge, USA
Dec 10, 2024

The development of the iPS cell technology has revolutionized our ability to study development and diseases in defined in vitro cell culture systems. The talk will focus on Rett Syndrome and discuss two topics: (i) the use of gene editing as an approach to therapy and (ii) the role of MECP2 in gene expression (i) The mutation of the X-linked MECP2 gene is causative for the disease. In a female patient, every cell has a wt copy that is, however, in 50% of the cells located on the inactive X chromosome. We have used epigenetic gene editing tools to activate the wt MECP2 allele on the inactive X chromosome. (ii) MECP2 is thought to act as repressor of gene expression. I will present data which show that MECP2 binds to Pol II and acts as an activator for thousands of genes. The target genes are significantly enriched for Autism related genes. Our data challenge the established model of MECP2’s role in gene expression and suggest novel therapeutic approaches.

SeminarNeuroscience

Spatial Organization of Cellular Reactive States in Human Brain Cancer

Sten Linnarsson
Karolinska Institute Sweden
May 21, 2024
SeminarPsychology

Enabling witnesses to actively explore faces and reinstate study-test pose during a lineup increases discrimination accuracy

Heather Flowe
University of Birmingham
Apr 21, 2024

In 2014, the US National Research Council called for the development of new lineup technologies to increase eyewitness identification accuracy (National Research Council, 2014). In a police lineup, a suspect is presented alongside multiple individuals known to be innocent who resemble the suspect in physical appearance know as fillers. A correct identification decision by an eyewitness can lead to a guilty suspect being convicted or an innocent suspect being exonerated from suspicion. An incorrect decision can result in the perpetrator remaining at large, or even a wrongful conviction of a mistakenly identified person. Incorrect decisions carry considerable human and financial costs, so it is essential to develop and enact lineup procedures that maximise discrimination accuracy, or the witness’ ability to distinguish guilty from innocent suspects. This talk focuses on new technology and innovation in the field of eyewitness identification. We will focus on the interactive lineup, which is a procedure that we developed based on research and theory from the basic science literature on face perception and recognition. The interactive lineup enables witnesses to actively explore and dynamically view the lineup members. The procedure has been shown to maximize discrimination accuracy, which is the witness’ ability to discriminate guilty from innocent suspects. The talk will conclude by reflecting on emerging technological frontiers and research opportunities.

SeminarNeuroscience

Stability of visual processing in passive and active vision

Tobias Rose
Institute of Experimental Epileptology and Cognition Research University of Bonn Medical Center
Mar 27, 2024

The visual system faces a dual challenge. On the one hand, features of the natural visual environment should be stably processed - irrespective of ongoing wiring changes, representational drift, and behavior. On the other hand, eye, head, and body motion require a robust integration of pose and gaze shifts in visual computations for a stable perception of the world. We address these dimensions of stable visual processing by studying the circuit mechanism of long-term representational stability, focusing on the role of plasticity, network structure, experience, and behavioral state while recording large-scale neuronal activity with miniature two-photon microscopy.

SeminarNeuroscienceRecording

Reimagining the neuron as a controller: A novel model for Neuroscience and AI

Dmitri 'Mitya' Chklovskii
Flatiron Institute, Center for Computational Neuroscience
Feb 4, 2024

We build upon and expand the efficient coding and predictive information models of neurons, presenting a novel perspective that neurons not only predict but also actively influence their future inputs through their outputs. We introduce the concept of neurons as feedback controllers of their environments, a role traditionally considered computationally demanding, particularly when the dynamical system characterizing the environment is unknown. By harnessing a novel data-driven control framework, we illustrate the feasibility of biological neurons functioning as effective feedback controllers. This innovative approach enables us to coherently explain various experimental findings that previously seemed unrelated. Our research has profound implications, potentially revolutionizing the modeling of neuronal circuits and paving the way for the creation of alternative, biologically inspired artificial neural networks.

SeminarPsychology

Characterising Representations of Goal Obstructiveness and Uncertainty Across Behavior, Physiology, and Brain Activity Through a Video Game Paradigm

Mi Xue Tan
University of Geneva
Dec 17, 2023

The nature of emotions and their neural underpinnings remain debated. Appraisal theories such as the component process model propose that the perception and evaluation of events (appraisal) is the key to eliciting the range of emotions we experience. Here we study whether the framework of appraisal theories provides a clearer account for the differentiation of emotional episodes and their functional organisation in the brain. We developed a stealth game to manipulate appraisals in a systematic yet immersive way. The interactive nature of video games heightens self-relevance through the experience of goal-directed action or reaction, evoking strong emotions. We show that our manipulations led to changes in behaviour, physiology and brain activations.

SeminarNeuroscience

Astrocyte reprogramming / activation and brain homeostasis

Thomaidou Dimitra
Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
Dec 12, 2023

Astrocytes are multifunctional glial cells, implicated in neurogenesis and synaptogenesis, supporting and fine-tuning neuronal activity and maintaining brain homeostasis by controlling blood-brain barrier permeability. During the last years a number of studies have shown that astrocytes can also be converted into neurons if they force-express neurogenic transcription factors or miRNAs. Direct astrocytic reprogramming to induced-neurons (iNs) is a powerful approach for manipulating cell fate, as it takes advantage of the intrinsic neural stem cell (NSC) potential of brain resident reactive astrocytes. To this end, astrocytic cell fate conversion to iNs has been well-established in vitro and in vivo using combinations of transcription factors (TFs) or chemical cocktails. Challenging the expression of lineage-specific TFs is accompanied by changes in the expression of miRNAs, that post-transcriptionally modulate high numbers of neurogenesis-promoting factors and have therefore been introduced, supplementary or alternatively to TFs, to instruct direct neuronal reprogramming. The neurogenic miRNA miR-124 has been employed in direct reprogramming protocols supplementary to neurogenic TFs and other miRNAs to enhance direct neurogenic conversion by suppressing multiple non-neuronal targets. In our group we aimed to investigate whether miR-124 is sufficient to drive direct reprogramming of astrocytes to induced-neurons (iNs) on its own both in vitro and in vivo and elucidate its independent mechanism of reprogramming action. Our in vitro data indicate that miR-124 is a potent driver of the reprogramming switch of astrocytes towards an immature neuronal fate. Elucidation of the molecular pathways being triggered by miR-124 by RNA-seq analysis revealed that miR-124 is sufficient to instruct reprogramming of cortical astrocytes to immature induced-neurons (iNs) in vitro by down-regulating genes with important regulatory roles in astrocytic function. Among these, the RNA binding protein Zfp36l1, implicated in ARE-mediated mRNA decay, was found to be a direct target of miR-124, that be its turn targets neuronal-specific proteins participating in cortical development, which get de-repressed in miR-124-iNs. Furthermore, miR-124 is potent to guide direct neuronal reprogramming of reactive astrocytes to iNs of cortical identity following cortical trauma, a novel finding confirming its robust reprogramming action within the cortical microenvironment under neuroinflammatory conditions. In parallel to their reprogramming properties, astrocytes also participate in the maintenance of blood-brain barrier integrity, which ensures the physiological functioning of the central nervous system and gets affected contributing to the pathology of several neurodegenerative diseases. To study in real time the dynamic physical interactions of astrocytes with brain vasculature under homeostatic and pathological conditions, we performed 2-photon brain intravital imaging in a mouse model of systemic neuroinflammation, known to trigger astrogliosis and microgliosis and to evoke changes in astrocytic contact with brain vasculature. Our in vivo findings indicate that following neuroinflammation the endfeet of activated perivascular astrocytes lose their close proximity and physiological cross-talk with vasculature, however this event is at compensated by the cross-talk of astrocytes with activated microglia, safeguarding blood vessel coverage and maintenance of blood-brain integrity.

SeminarPsychology

10 “simple rules” for socially responsible science

Alon Zivony
University of Sheffield
Dec 10, 2023

Guidelines concerning the potentially harmful effects of scientific studies have historically focused on minimizing risk for participants. However, studies can also indirectly inflict harm on individuals and social groups through how they are designed, reported, and disseminated. As evidenced by recent criticisms and retractions of high-profile studies dealing with a wide variety of social issues, there is a scarcity of resources and guidance on how one can conduct research in a socially responsible manner. As such, even motivated researchers might publish work that has negative social impacts due to a lack of awareness. To address this, we proposed 10 recommendations (“simple rules”) for researchers who wish to conduct more socially responsible science. These recommendations cover major considerations throughout the life cycle of a study from inception to dissemination. They are not aimed to be a prescriptive list or a deterministic code of conduct. Rather, they are meant to help motivated scientists to reflect on their social responsibility as researchers and actively engage with the potential social impact of their research.

SeminarNeuroscience

Sensory Consequences of Visual Actions

Martin Rolfs
Humboldt-Universität zu Berlin
Dec 7, 2023

We use rapid eye, head, and body movements to extract information from a new part of the visual scene upon each new gaze fixation. But the consequences of such visual actions go beyond their intended sensory outcomes. On the one hand, intrinsic consequences accompany movement preparation as covert internal processes (e.g., predictive changes in the deployment of visual attention). On the other hand, visual actions have incidental consequences, side effects of moving the sensory surface to its intended goal (e.g., global motion of the retinal image during saccades). In this talk, I will present studies in which we investigated intrinsic and incidental sensory consequences of visual actions and their sensorimotor functions. Our results provide insights into continuously interacting top-down and bottom-up sensory processes, and they reify the necessity to study perception in connection to motor behavior that shapes its fundamental processes.

SeminarNeuroscience

Neuromodulation of subjective experience

Siri Leknes
University of Oslo
Nov 13, 2023

Many psychoactive substances are used with the aim of altering experience, e.g. as analgesics, antidepressants or antipsychotics. These drugs act on specific receptor systems in the brain, including the opioid, serotonergic and dopaminergic systems. In this talk, I will summarise human drug studies targeting opioid receptors and their role for human experience, with focus on the experience of pain, stress, mood, and social connection. Opioids are only indicated for analgesia, due to their potential to cause addiction. When these regulations occurred, other known effects were relegated to side effects. This may be the cause of the prevalent myth that opioids are the most potent painkillers, despite evidence from head-to-head trials, Cochrane reviews and network meta-analyses that opioids are not superior to non-opioid analgesics in the treatment of acute or chronic non-cancer pain. However, due to the variability and diversity of opioid effects across contexts and experiences, some people under some circumstances may indeed benefit from prolonged treatment. I will present data on individual differences in opioid effects due to participant sex and stress induction. Understanding the effects of these commonly used medications on other aspects of the human experience is important to ensure correct use and to prevent unnecessary pain and addiction risk.

SeminarNeuroscienceRecording

Epilepsy genetics 2023: From research to advanced clinical genetic test interpretation

Dennis Lal
Cleveland Clinic
Jun 20, 2023

The presentation will provide an overview of the expanding role of genetic factors in epilepsy. It will delve into the fundamentals of this field and elucidate how digital tools and resources can aid in the re-evaluation of genetic test results. In the initial segment of the presentation, Dr. Lal will examine the advancements made over the past two decades regarding the genetic architecture of various epilepsy types. Additionally, he will present research studies in which he has actively participated, offering concrete examples. Subsequently, during the second part of the talk, Dr. Lal will share the ongoing research projects that focus on epilepsy genetics, bioinformatics, and health record data science.

SeminarCognition

Prosody in the voice, face, and hands changes which words you hear

Hans Rutger Bosker
Donders Institute of Radboud University
May 22, 2023

Speech may be characterized as conveying both segmental information (i.e., about vowels and consonants) as well as suprasegmental information - cued through pitch, intensity, and duration - also known as the prosody of speech. In this contribution, I will argue that prosody shapes low-level speech perception, changing which speech sounds we hear. Perhaps the most notable example of how prosody guides word recognition is the phenomenon of lexical stress, whereby suprasegmental F0, intensity, and duration cues can distinguish otherwise segmentally identical words, such as "PLAto" vs. "plaTEAU" in Dutch. Work from our group showcases the vast variability in how different talkers produce stressed vs. unstressed syllables, while also unveiling the remarkable flexibility with which listeners can learn to handle this between-talker variability. It also emphasizes that lexical stress is a multimodal linguistic phenomenon, with the voice, lips, and even hands conveying stress in concert. In turn, human listeners actively weigh these multisensory cues to stress depending on the listening conditions at hand. Finally, lexical stress is presented as having a robust and lasting impact on low-level speech perception, even down to changing vowel perception. Thus, prosody - in all its multisensory forms - is a potent factor in speech perception, determining what speech sounds we hear.

SeminarNeuroscience

Precise spatio-temporal spike patterns in cortex and model

Sonia Gruen
Forschungszentrum Jülich, Germany
Apr 25, 2023

The cell assembly hypothesis postulates that groups of coordinated neurons form the basis of information processing. Here, we test this hypothesis by analyzing massively parallel spiking activity recorded in monkey motor cortex during a reach-to-grasp experiment for the presence of significant ms-precise spatio-temporal spike patterns (STPs). For this purpose, the parallel spike trains were analyzed for STPs by the SPADE method (Stella et al, 2019, Biosystems), which detects, counts and evaluates spike patterns for their significance by the use of surrogates (Stella et al, 2022 eNeuro). As a result we find STPs in 19/20 data sets (each of 15min) from two monkeys, but only a small fraction of the recorded neurons are involved in STPs. To consider the different behavioral states during the task, we analyzed the data in a quasi time-resolved analysis by dividing the data into behaviorally relevant time epochs. The STPs that occur in the various epochs are specific to behavioral context - in terms of neurons involved and temporal lags between the spikes of the STP. Furthermore we find, that the STPs often share individual neurons across epochs. Since we interprete the occurrence of a particular STP as the signature of a particular active cell assembly, our interpretation is that the neurons multiplex their cell assembly membership. In a related study, we model these findings by networks with embedded synfire chains (Kleinjohann et al, 2022, bioRxiv 2022.08.02.502431).

SeminarNeuroscienceRecording

Analogical Reasoning and Generalization for Interactive Task Learning in Physical Machines

Shiwali Mohan
Palo Alto Research Center
Mar 30, 2023

Humans are natural teachers; learning through instruction is one of the most fundamental ways that we learn. Interactive Task Learning (ITL) is an emerging research agenda that studies the design of complex intelligent robots that can acquire new knowledge through natural human teacher-robot learner interactions. ITL methods are particularly useful for designing intelligent robots whose behavior can be adapted by humans collaborating with them. In this talk, I will summarize our recent findings on the structure that human instruction naturally has and motivate an intelligent system design that can exploit their structure. The system – AILEEN – is being developed using the common model of cognition. Architectures that implement the Common Model of Cognition - Soar, ACT-R, and Sigma - have a prominent place in research on cognitive modeling as well as on designing complex intelligent agents. However, they miss a critical piece of intelligent behavior – analogical reasoning and generalization. I will introduce a new memory – concept memory – that integrates with a common model of cognition architecture and supports ITL.

SeminarNeuroscience

Uncovering the molecular effectors of diet and exercise

Jonathan Long
Stanford University
Mar 27, 2023

Despite the profound effects of nutrition and physical activity on human health, our understanding of the molecules mediating the salutary effects of specific foods or activities remains remarkably limited. Here, we share our ongoing studies that use unbiased and high-resolution metabolomics technologies to uncover the molecules and molecular effectors of diet and exercise. We describe how exercise stimulates the production of Lac-Phe, a blood-borne signaling metabolite that suppresses feeding and obesity. Ablation of Lac-Phe biosynthesis in mice increases food intake and obesity after exercise. We also describe the discovery of an orphan metabolite, BHB-Phe. Ketosis-inducible BHB-Phe is a congener of exercise-inducible Lac-Phe, produced in CNDP2+ cells when levels of BHB are high, and functions to lower body weight and adiposity in ketosis. Our data uncover an unexpected and underappreciated signaling role for metabolic fuel derivatives in mediating the cardiometabolic benefits of diet and exercise. These data also suggest that diet and exercise may mediate their physiologic effects on energy balance via a common family of molecules and overlapping signaling pathways.

SeminarNeuroscienceRecording

Are place cells just memory cells? Probably yes

Stefano Fusi
Columbia University, New York
Mar 21, 2023

Neurons in the rodent hippocampus appear to encode the position of the animal in physical space during movement. Individual ``place cells'' fire in restricted sub-regions of an environment, a feature often taken as evidence that the hippocampus encodes a map of space that subserves navigation. But these same neurons exhibit complex responses to many other variables that defy explanation by position alone, and the hippocampus is known to be more broadly critical for memory formation. Here we elaborate and test a theory of hippocampal coding which produces place cells as a general consequence of efficient memory coding. We constructed neural networks that actively exploit the correlations between memories in order to learn compressed representations of experience. Place cells readily emerged in the trained model, due to the correlations in sensory input between experiences at nearby locations. Notably, these properties were highly sensitive to the compressibility of the sensory environment, with place field size and population coding level in dynamic opposition to optimally encode the correlations between experiences. The effects of learning were also strongly biphasic: nearby locations are represented more similarly following training, while locations with intermediate similarity become increasingly decorrelated, both distance-dependent effects that scaled with the compressibility of the input features. Using virtual reality and 2-photon functional calcium imaging in head-fixed mice, we recorded the simultaneous activity of thousands of hippocampal neurons during virtual exploration to test these predictions. Varying the compressibility of sensory information in the environment produced systematic changes in place cell properties that reflected the changing input statistics, consistent with the theory. We similarly identified representational plasticity during learning, which produced a distance-dependent exchange between compression and pattern separation. These results motivate a more domain-general interpretation of hippocampal computation, one that is naturally compatible with earlier theories on the circuit's importance for episodic memory formation. Work done in collaboration with James Priestley, Lorenzo Posani, Marcus Benna, Attila Losonczy.

SeminarNeuroscienceRecording

Autopoiesis and Enaction in the Game of Life

Randall Beer
Indiana University
Mar 16, 2023

Enaction plays a central role in the broader fabric of so-called 4E (embodied, embedded, extended, enactive) cognition. Although the origin of the enactive approach is widely dated to the 1991 publication of the book "The Embodied Mind" by Varela, Thompson and Rosch, many of the central ideas trace to much earlier work. Over 40 years ago, the Chilean biologists Humberto Maturana and Francisco Varela put forward the notion of autopoiesis as a way to understand living systems and the phenomena that they generate, including cognition. Varela and others subsequently extended this framework to an enactive approach that places biological autonomy at the foundation of situated and embodied behavior and cognition. I will describe an attempt to place Maturana and Varela's original ideas on a firmer foundation by studying them within the context of a toy model universe, John Conway's Game of Life (GoL) cellular automata. This work has both pedagogical and theoretical goals. Simple concrete models provide an excellent vehicle for introducing some of the core concepts of autopoiesis and enaction and explaining how these concepts fit together into a broader whole. In addition, a careful analysis of such toy models can hone our intuitions about these concepts, probe their strengths and weaknesses, and move the entire enterprise in the direction of a more mathematically rigorous theory. In particular, I will identify the primitive processes that can occur in GoL, show how these can be linked together into mutually-supporting networks that underlie persistent bounded entities, map the responses of such entities to environmental perturbations, and investigate the paths of mutual perturbation that these entities and their environments can undergo.

SeminarNeuroscience

A specialized role for entorhinal attractor dynamics in combining path integration and landmarks during navigation

Malcolm Campbell
Harvard
Mar 8, 2023

During navigation, animals estimate their position using path integration and landmarks. In a series of two studies, we used virtual reality and electrophysiology to dissect how these inputs combine to generate the brain’s spatial representations. In the first study (Campbell et al., 2018), we focused on the medial entorhinal cortex (MEC) and its set of navigationally-relevant cell types, including grid cells, border cells, and speed cells. We discovered that attractor dynamics could explain an array of initially puzzling MEC responses to virtual reality manipulations. This theoretical framework successfully predicted both MEC grid cell responses to additional virtual reality manipulations, as well as mouse behavior in a virtual path integration task. In the second study (Campbell*, Attinger* et al., 2021), we asked whether these principles generalize to other navigationally-relevant brain regions. We used Neuropixels probes to record thousands of neurons from MEC, primary visual cortex (V1), and retrosplenial cortex (RSC). In contrast to the prevailing view that “everything is everywhere all at once,” we identified a unique population of MEC neurons, overlapping with grid cells, that became active with striking spatial periodicity while head-fixed mice ran on a treadmill in darkness. These neurons exhibited unique cue-integration properties compared to other MEC, V1, or RSC neurons: they remapped more readily in response to conflicts between path integration and landmarks; they coded position prospectively as opposed to retrospectively; they upweighted path integration relative to landmarks in conditions of low visual contrast; and as a population, they exhibited a lower-dimensional activity structure. Based on these results, our current view is that MEC attractor dynamics play a privileged role in resolving conflicts between path integration and landmarks during navigation. Future work should include carefully designed causal manipulations to rigorously test this idea, and expand the theoretical framework to incorporate notions of uncertainty and optimality.

SeminarNeuroscienceRecording

Active vision in Drosophila

Lisa Fenk
Max Planck Institute for Biological Intelligence, Munich
Dec 11, 2022
SeminarNeuroscienceRecording

Nonlinear computations in spiking neural networks through multiplicative synapses

M. Nardin
IST Austria
Nov 8, 2022

The brain efficiently performs nonlinear computations through its intricate networks of spiking neurons, but how this is done remains elusive. While recurrent spiking networks implementing linear computations can be directly derived and easily understood (e.g., in the spike coding network (SCN) framework), the connectivity required for nonlinear computations can be harder to interpret, as they require additional non-linearities (e.g., dendritic or synaptic) weighted through supervised training. Here we extend the SCN framework to directly implement any polynomial dynamical system. This results in networks requiring multiplicative synapses, which we term the multiplicative spike coding network (mSCN). We demonstrate how the required connectivity for several nonlinear dynamical systems can be directly derived and implemented in mSCNs, without training. We also show how to precisely carry out higher-order polynomials with coupled networks that use only pair-wise multiplicative synapses, and provide expected numbers of connections for each synapse type. Overall, our work provides an alternative method for implementing nonlinear computations in spiking neural networks, while keeping all the attractive features of standard SCNs such as robustness, irregular and sparse firing, and interpretable connectivity. Finally, we discuss the biological plausibility of mSCNs, and how the high accuracy and robustness of the approach may be of interest for neuromorphic computing.

SeminarNeuroscience

Identifying central mechanisms of glucocorticoid circadian rhythm dysfunction in breast cancer

Jeremy C. Borniger
Cold Spring Harbor Laboratory
Oct 17, 2022

The circadian release of endogenous glucocorticoids is essential in preparing and synchronizing the body’s daily physiological needs. Disruption in the rhythmic activity of glucocorticoids has been observed in individuals with a variety of cancer types, and blunting of this rhythm has been shown to predict cancer mortality and declines in quality of life. This suggests that a disrupted glucocorticoid rhythm is potentially a shared phenotype across cancers. However, where this phenomenon is driven by the cancer itself, and the causal mechanisms that link glucocorticoid rhythm dysfunction and cancer outcomes remain preliminary at best. The regulation of daily glucocorticoid activity has been well-characterized and is maintained, in part, by the coordinated response of the hypothalamic-pituitary-adrenal (HPA) axis, consisting of the suprachiasmatic nucleus (SCN) and corticotropin-releasing hormone-expressing neurons of the paraventricular nucleus of the hypothalamus (PVNCRH). Consequently, we set out to examine if cancer-induced glucocorticoid dysfunction is regulated by disruptions within these hypothalamic nuclei. In comparison to their tumor-free baseline, mammary tumor-bearing mice exhibited a blunting of glucocorticoid rhythms across multiple timepoints throughout the day, as measured by the overall levels and the slope of fecal corticosterone rhythms, during tumor progression. We further examined how peripheral tumors shape hypothalamic activity within the brain. Serial two-photon tomography for whole-brain cFos imaging suggests a disrupted activation of the PVN in mice with tumors. Additionally, we found GFP labeled CRH+ neurons within the PVN after injection of pseudorabies virus expressing GFP into the tumor, pointing to the PVN as a primary target disrupted by mammary tumors. Preliminary in vivo fiber photometry data show that PVNCRH neurons exhibit enhanced calcium activity during tumor progression, as compared to baseline (no tumor) activity. Taken together, this suggests that there may be an overactive HPA response during tumor progression, which in turn, may result in a subsequent negative feedback on glucocorticoid rhythms. Current studies are examining whether tumor progression modulates SCN calcium activity, how the transcriptional profile of PVNCRH neurons is changed, and test if manipulation of the neurocircuitry surrounding glucocorticoid rhythmicity alters tumor characteristics.

SeminarNeuroscience

Root causes and possible solutions to academic bullying in higher education

Morteza Mahmoudi
Michigan State University, USA
Sep 27, 2022

Academic bullying is a serious issue that affects all disciplines and people of all levels of experience. To create a truly safe, productive, and vibrant environment in academia requires coordinated and collaborative input as well as the action of a variety of stakeholders, including scholarly communities, funding agencies, and institutions. This talk will focus on a framework of integrated responding, in which stakeholders as responsible and response-able parties could proactively collaborate and coordinate to reduce the incidence and consequences of academic bullying while at the same time building constructive academic cultures. The outcome of such a framework would be to create novel entities and actions that accelerate successful responses to academic bullying.

SeminarNeuroscienceRecording

Redox and mitochondrial dysregulation in epilepsy

Manisha Patel
University of Colorado
Sep 20, 2022

Epileptic seizures render the brain uniquely dependent on energy producing pathways. Studies in our laboratory have been focused on the role of redox processes and mitochondria in the context of abnormal neuronal excitability associated with epilepsy. We have shown that that status epilepticus (SE) alters mitochondrial and cellular redox status, energetics and function and conversely, that reactive oxygen species and resultant dysfunction can lead to chronic epilepsy. Oxidative stress and neuroinflammatory pathways have considerable crosstalk and targeting redox processes has recently been shown to control neuroinflammation and excitability. Understanding the role of metabolic and redox processes can enable the development of novel therapeutics to control epilepsy and/or its comorbidities.

SeminarNeuroscience

Decision Making and the Brain

Arjun Ramakrishnan
IIT, Kanpur
Sep 5, 2022

In this talk, we will examine human behavior from the perspective of the choices we make every day. We will study the role of the brain in enabling these decisions and discuss some simple computational models of decision making and the neural basis. Towards the end, we will have a short, interactive session to engage in some easy decisions that will help us discover our own biases.

SeminarPhysics of LifeRecording

Odd dynamics of living chiral crystals

Alexander Mietke
MIT
Aug 14, 2022

The emergent dynamics exhibited by collections of living organisms often shows signatures of symmetries that are broken at the single-organism level. At the same time, organism development itself encompasses a well-coordinated sequence of symmetry breaking events that successively transform a single, nearly isotropic cell into an animal with well-defined body axis and various anatomical asymmetries. Combining these key aspects of collective phenomena and embryonic development, we describe here the spontaneous formation of hydrodynamically stabilized active crystals made of hundreds of starfish embryos that gather during early development near fluid surfaces. We describe a minimal hydrodynamic theory that is fully parameterized by experimental measurements of microscopic interactions among embryos. Using this theory, we can quantitatively describe the stability, formation and rotation of crystals and rationalize the emergence of mechanical properties that carry signatures of an odd elastic material. Our work thereby quantitatively connects developmental symmetry breaking events on the single-embryo level with remarkable macroscopic material properties of a novel living chiral crystal system.

SeminarPhysics of LifeRecording

Active mechanics of sea star oocytes

Peter Foster
Brandeis University
Jul 17, 2022

The cytoskeleton has the remarkable ability to self-organize into active materials which underlie diverse cellular processes ranging from motility to cell division. Actomyosin is a canonical example of an active material, which generates cellularscale contractility in part through the forces exerted by myosin motors on actin filaments. While the molecular players underlying actomyosin contractility have been well characterized, how cellular-scale deformation in disordered actomyosin networks emerges from filament-scale interactions is not well understood. In this talk, I’ll present work done in collaboration with Sebastian Fürthauer and Nikta Fakhri addressing this question in vivo using the meiotic surface contraction wave seen in oocytes of the bat star Patiria miniata as a model system. By perturbing actin polymerization, we find that the cellular deformation rate is a nonmonotonic function of cortical actin density peaked near the wild type density. To understand this, we develop an active fluid model coarse-grained from filament-scale interactions and find quantitative agreement with the measured data. The model makes further predictions, including the surprising prediction that deformation rate decreases with increasing motor concentration. We test these predictions through protein overexpression and find quantitative agreement. Taken together, this work is an important step for bridging the molecular and cellular length scales for cytoskeletal networks in vivo.

SeminarNeuroscienceRecording

Canonical neural networks perform active inference

Takuya Isomura
RIKEN CBS
Jun 9, 2022

The free-energy principle and active inference have received a significant attention in the fields of neuroscience and machine learning. However, it remains to be established whether active inference is an apt explanation for any given neural network that actively exchanges with its environment. To address this issue, we show that a class of canonical neural networks of rate coding models implicitly performs variational Bayesian inference under a well-known form of partially observed Markov decision process model (Isomura, Shimazaki, Friston, Commun Biol, 2022). Based on the proposed theory, we demonstrate that canonical neural networks—featuring delayed modulation of Hebbian plasticity—can perform planning and adaptive behavioural control in the Bayes optimal manner, through postdiction of their previous decisions. This scheme enables us to estimate implicit priors under which the agent’s neural network operates and identify a specific form of the generative model. The proposed equivalence is crucial for rendering brain activity explainable to better understand basic neuropsychology and psychiatric disorders. Moreover, this notion can dramatically reduce the complexity of designing self-learning neuromorphic hardware to perform various types of tasks.

SeminarNeuroscience

In pursuit of a universal, biomimetic iBCI decoder: Exploring the manifold representations of action in the motor cortex

Lee Miller
Northwestern University
May 19, 2022

My group pioneered the development of a novel intracortical brain computer interface (iBCI) that decodes muscle activity (EMG) from signals recorded in the motor cortex of animals. We use these synthetic EMG signals to control Functional Electrical Stimulation (FES), which causes the muscles to contract and thereby restores rudimentary voluntary control of the paralyzed limb. In the past few years, there has been much interest in the fact that information from the millions of neurons active during movement can be reduced to a small number of “latent” signals in a low-dimensional manifold computed from the multiple neuron recordings. These signals can be used to provide a stable prediction of the animal’s behavior over many months-long periods, and they may also provide the means to implement methods of transfer learning across individuals, an application that could be of particular importance for paralyzed human users. We have begun to examine the representation within this latent space, of a broad range of behaviors, including well-learned, stereotyped movements in the lab, and more natural movements in the animal’s home cage, meant to better represent a person’s daily activities. We intend to develop an FES-based iBCI that will restore voluntary movement across a broad range of motor tasks without need for intermittent recalibration. However, the nonlinearities and context dependence within this low-dimensional manifold present significant challenges.

SeminarNeuroscienceRecording

Computational modelling of neurotransmitter release

Yulia Timofeeva
University of Warwick
May 17, 2022

Synaptic transmission provides the basis for neuronal communication. When an action-potential propagates through the axonal arbour, it activates voltage-gated Ca2+ channels located in the vicinity of release-ready synaptic vesicles docked at the presynaptic active zone. Ca2+ ions enter the presynaptic terminal and activate the vesicular Ca2+ sensor, thereby triggering neurotransmitter release. This whole process occurs on a timescale of a few milliseconds. In addition to fast, synchronous release, which keeps pace with action potentials, many synapses also exhibit delayed asynchronous release that persists for tens to hundreds of milliseconds. In this talk I will demonstrate how experimentally constrained computational modelling of underlying biological processes can complement laboratory studies (using electrophysiology and imaging techniques) and provide insights into the mechanisms of synaptic transmission.

SeminarNeuroscienceRecording

The balance of excitation and inhibition and a canonical cortical computation

Yashar Ahmadian
Cambridge, UK
Apr 26, 2022

Excitatory and inhibitory (E & I) inputs to cortical neurons remain balanced across different conditions. The balanced network model provides a self-consistent account of this observation: population rates dynamically adjust to yield a state in which all neurons are active at biological levels, with their E & I inputs tightly balanced. But global tight E/I balance predicts population responses with linear stimulus-dependence and does not account for systematic cortical response nonlinearities such as divisive normalization, a canonical brain computation. However, when necessary connectivity conditions for global balance fail, states arise in which only a localized subset of neurons are active and have balanced inputs. We analytically show that in networks of neurons with different stimulus selectivities, the emergence of such localized balance states robustly leads to normalization, including sublinear integration and winner-take-all behavior. An alternative model that exhibits normalization is the Stabilized Supralinear Network (SSN), which predicts a regime of loose, rather than tight, E/I balance. However, an understanding of the causal relationship between E/I balance and normalization in SSN and conditions under which SSN yields significant sublinear integration are lacking. For weak inputs, SSN integrates inputs supralinearly, while for very strong inputs it approaches a regime of tight balance. We show that when this latter regime is globally balanced, SSN cannot exhibit strong normalization for any input strength; thus, in SSN too, significant normalization requires localized balance. In summary, we causally and quantitatively connect a fundamental feature of cortical dynamics with a canonical brain computation. Time allowing I will also cover our work extending a normative theoretical account of normalization which explains it as an example of efficient coding of natural stimuli. We show that when biological noise is accounted for, this theory makes the same prediction as the SSN: a transition to supralinear integration for weak stimuli.

SeminarNeuroscience

Astroglial modulation of the antidepressant action of deep brain and bright light stimulation

Nasser Haddjeri
Stem Cell And Brain Research Institute, INSERM 1208, Bron, France
Apr 7, 2022

Even if major depression is now the most common of psychiatric disorders, successful antidepressant treatments are still difficult to achieve. Therefore, a better understanding of the mechanisms of action of current antidepressant treatments is needed to ultimately identify new targets and enhance beneficial effects. Given the intimate relationships between astrocytes and neurons at synapses and the ability of astrocytes to "sense" neuronal communication and release gliotransmitters, an attractive hypothesis is emerging stating that the effects of antidepressants on brain function could be, at least in part, modulated by direct influences of astrocytes on neuronal networks. We will present two preclinical studies revealing a permissive role of glia in the antidepressant response: i) Control of the antidepressant-like effects of rat prefrontal cortex Deep Brain Stimulation (DBS) by astroglia, ii) Modulation of antidepressant efficacy of Bright Light Stimulation (BLS) by lateral habenula astroglia. Therefore, it is proposed that an unaltered neuronal-glial system constitutes a major prerequisite to optimize antidepressant efficacy of DBS or BLS. Collectively, these results pave also the way to the development of safer and more effective antidepressant strategies.

SeminarOpen SourceRecording

Mesmerize: A blueprint for shareable and reproducible analysis of calcium imaging data

Kushal Kolar
University of North Carolina at Chapel Hill
Apr 5, 2022

Mesmerize is a platform for the annotation and analysis of neuronal calcium imaging data. Mesmerize encompasses the entire process of calcium imaging analysis from raw data to interactive visualizations. Mesmerize allows you to create FAIR-functionally linked datasets that are easy to share. The analysis tools are applicable for a broad range of biological experiments and come with GUI interfaces that can be used without requiring a programming background.

SeminarNeuroscienceRecording

Remembering immunity: Neuronal representation of immune responses

Tamar Koren
Rolls lab, Technion - Israel Institute of Technology
Mar 29, 2022

Accumulating data indicate that the brain can affect immunity, as evidenced, for example, by the effects of stress, stroke, and reward system activity on the peripheral immune system. However, our understanding of this neuroimmune interaction is still limited. Importantly, we do not know how the brain evaluates and represents the state of the immune system. In this talk, I will present our latest study from our lab, designed to test the existence of immune-related information in the brain and determine its relevance to immune regulation. We hypothesized that the InsCtx, specifically the posterior InsCtx (as a primary cortical site of interoception in the brain), is especially suited to contain such a representation of the immune system. Using activity-dependent cell labeling in mice (FosTRAP), we captured neuronal ensembles in the InsCtx that were active under two different inflammatory conditions (dextran sulfate sodium [DSS]-induced colitis and zymosan-induced peritonitis). Chemogenetic reactivation of these neuronal ensembles was sufficient to broadly retrieve the inflammatory state under which these neurons were captured. Moreover, using retrograde neuronal tracing, we found an anatomical efferent pathway linking these InsCtx neurons to the inflamed peripheral sites. Taken together, we show that the brain can store and retrieve specific immune responses, extending the classical concept of immunological memory to neuronal representations of inflammatory information.

SeminarPhysics of LifeRecording

Intrinsic Rhythms in a Giant Single-Celled Organism and the Interplay with Time-Dependent Drive, Explored via Self-Organized Macroscopic Waves

Eldad Afik
California Institute of Technology
Mar 27, 2022

Living Systems often seem to follow, in addition to external constraints and interactions, an intrinsic predictive model of the world — a defining trait of Anticipatory Systems. Here we study rhythmic behaviour in Caulerpa, a marine green alga, which appears to predict the day/night light cycle. Caulerpa consists of differentiated organs resembling leaves, stems and roots. While an individual can exceed a meter in size, it is a single multinucleated giant cell. Active transport has been hypothesized to play a key role in organismal development. It has been an open question in the literature whether rhythmic transport phenomena in this organism are of autonomous circadian nature. Using Raspberry-Pi cameras, we track over weeks the morphogenesis of tens of samples concurrently, while tracing at resolution of tens of seconds the variation of the green coverage. The latter reveals waves propagating over centimeters within few hours, and is attributed to chloroplast redistribution at whole-organism scale. Our observations of algal segments regenerating under 12-hour light/dark cycles indicate that the initiation of the waves precedes the external light change. Using time-frequency analysis, we find that the temporal spectrum of these green pulses contains a circadian period. The latter persists over days even under constant illumination, indicative of its autonomous nature. We further explore the system under non-circadian periods, to reveal how the spectral content changes in response. Time-keeping and synchronization are recurring themes in biological research at various levels of description — from subcellular components to ecological systems. We present a seemingly primitive living system that exhibits apparent anticipatory behaviour. This research offers quantitative constraints for theoretical frameworks of such systems.

SeminarPhysics of LifeRecording

Exact coherent structures and transition to turbulence in a confined active nematic

Caleb Wagner
University of Nebraska-Lincoln
Feb 27, 2022

Active matter describes a class of systems that are maintained far from equilibrium by driving forces acting on the constituent particles. Here I will focus on confined active nematics, which exhibit especially rich flow behavior, ranging from structured patterns in space and time to disordered turbulent flows. To understand this behavior, I will take a deterministic dynamical systems approach, beginning with the hydrodynamic equations for the active nematic. This approach reveals that the infinite-dimensional phase space of all possible flow configurations is populated by Exact Coherent Structures (ECS), which are exact solutions of the hydrodynamic equations with distinct and regular spatiotemporal structure; examples include unstable equilibria, periodic orbits, and traveling waves. The ECS are connected by dynamical pathways called invariant manifolds. The main hypothesis in this approach is that turbulence corresponds to a trajectory meandering in the phase space, transitioning between ECS by traveling on the invariant manifolds. Similar approaches have been successful in characterizing high Reynolds number turbulence of passive fluids. Here, I will present the first systematic study of active nematic ECS and their invariant manifolds and discuss their role in characterizing the phenomenon of active turbulence.

SeminarNeuroscienceRecording

Metabolic spikes: from rogue electrons to Parkinson's

Chaitanya Chintaluri
Vogels Lab, IST Austria
Feb 22, 2022

Conventionally, neurons are thought to be cellular units that process synaptic inputs into synaptic spikes. However, it is well known that neurons can also spike spontaneously and display a rich repertoire of firing properties with no apparent functional relevance e.g. in in vitro cortical slice preparations. In this talk, I will propose a hypothesis according to which intrinsic excitability in neurons may be a survival mechanism to minimize toxic byproducts of the cell’s energy metabolism. In neurons, this toxicity can arise when mitochondrial ATP production stalls due to limited ADP. Under these conditions, electrons deviate from the electron transport chain to produce reactive oxygen species, disrupting many cellular processes and challenging cell survival. To mitigate this, neurons may engage in ADP-producing metabolic spikes. I will explore the validity of this hypothesis using computational models that illustrate the implications of synaptic and metabolic spiking, especially in the context of substantia nigra pars compacta dopaminergic neurons and their degeneration in Parkinson's disease.

SeminarNeuroscience

Attention to visual motion: shaping sensation into perception

Stefan Treue
German Primate Center - Leibniz Institute for Primate Research, Goettingen, Germany
Feb 20, 2022

Evolution has endowed primates, including humans, with a powerful visual system, seemingly providing us with a detailed perception of our surroundings. But in reality the underlying process is one of active filtering, enhancement and reshaping. For visual motion perception, the dorsal pathway in primate visual cortex and in particular area MT/V5 is considered to be of critical importance. Combining physiological and psychophysical approaches we have used the processing and perception of visual motion and area MT/V5 as a model for the interaction of sensory (bottom-up) signals with cognitive (top-down) modulatory influences that characterizes visual perception. Our findings document how this interaction enables visual cortex to actively generate a neural representation of the environment that combines the high-performance sensory periphery with selective modulatory influences for producing an “integrated saliency map’ of the environment.

SeminarNeuroscience

Keeping your Brain in Balance: the Ups and Downs of Homeostatic Plasticity (virtual)

Gina Turrigiano, PhD
Professor, Department of Biology, Brandeis University, USA
Feb 16, 2022

Our brains must generate and maintain stable activity patterns over decades of life, despite the dramatic changes in circuit connectivity and function induced by learning and experience-dependent plasticity. How do our brains acheive this balance between opposing need for plasticity and stability? Over the past two decades, we and others have uncovered a family of “homeostatic” negative feedback mechanisms that are theorized to stabilize overall brain activity while allowing specific connections to be reconfigured by experience. Here I discuss recent work in which we demonstrate that individual neocortical neurons in freely behaving animals indeed have a homeostatic activity set-point, to which they return in the face of perturbations. Intriguingly, this firing rate homeostasis is gated by sleep/wake states in a manner that depends on the direction of homeostatic regulation: upward-firing rate homeostasis occurs selectively during periods of active wake, while downward-firing rate homeostasis occurs selectively during periods of sleep, suggesting that an important function of sleep is to temporally segregate bidirectional plasticity. Finally, we show that firing rate homeostasis is compromised in an animal model of autism spectrum disorder. Together our findings suggest that loss of homeostatic plasticity in some neurological disorders may render central circuits unable to compensate for the normal perturbations induced by development and learning.

SeminarNeuroscienceRecording

Network mechanisms underlying representational drift in area CA1 of hippocampus

Alex Roxin
CRM, Barcelona
Feb 1, 2022

Recent chronic imaging experiments in mice have revealed that the hippocampal code exhibits non-trivial turnover dynamics over long time scales. Specifically, the subset of cells which are active on any given session in a familiar environment changes over the course of days and weeks. While some cells transition into or out of the code after a few sessions, others are stable over the entire experiment. The mechanisms underlying this turnover are unknown. Here we show that the statistics of turnover are consistent with a model in which non-spatial inputs to CA1 pyramidal cells readily undergo plasticity, while spatially tuned inputs are largely stable over time. The heterogeneity in stability across the cell assembly, as well as the decrease in correlation of the population vector of activity over time, are both quantitatively fit by a simple model with Gaussian input statistics. In fact, such input statistics emerge naturally in a network of spiking neurons operating in the fluctuation-driven regime. This correspondence allows one to map the parameters of a large-scale spiking network model of CA1 onto the simple statistical model, and thereby fit the experimental data quantitatively. Importantly, we show that the observed drift is entirely consistent with random, ongoing synaptic turnover. This synaptic turnover is, in turn, consistent with Hebbian plasticity related to continuous learning in a fast memory system.

SeminarNeuroscience

Predicting appearances

Sylvia Pont
Delft University of Technology
Feb 1, 2022

Visual appearance is an important factor in product and lighting design, and depends on the combination of form, materials, context, and lighting. Such design spaces are seemingly endless and full of optical as well as perceptual interactions. A systematic approach to navigate this space and to predict the resulting appearance can support designers in their iterative work flow, avoiding losing time on trial and error and offering understanding of the optical and perceptual effects. It should also allow artistic freedom to interactively vary the design, and enable easy communication to team members and clients. I will present examples of such approaches via canonical sets, simplifying design spaces in perception-based manners to arrive at intuitive presentations, with a focus on light(ing) design and material appearance.

SeminarPhysics of LifeRecording

Towards model-based control of active matter: active nematics and oscillator networks

Michael Norton
Rochester Institute of Technology
Jan 30, 2022

The richness of active matter's spatiotemporal patterns continues to capture our imagination. Shaping these emergent dynamics into pre-determined forms of our choosing is a grand challenge in the field. To complicate matters, multiple dynamical attractors can coexist in such systems, leading to initial condition-dependent dynamics. Consequently, non-trivial spatiotemporal inputs are generally needed to access these states. Optimal control theory provides a general framework for identifying such inputs and represents a promising computational tool for guiding experiments and interacting with various systems in soft active matter and biology. As an exemplar, I first consider an extensile active nematic fluid confined to a disk. In the absence of control, the system produces two topological defects that perpetually circulate. Optimal control identifies a time-varying active stress field that restructures the director field, flipping the system to its other attractor that rotates in the opposite direction. As a second, analogous case, I examine a small network of coupled Belousov-Zhabotinsky chemical oscillators that possesses two dominant attractors, two wave states of opposing chirality. Optimal control similarly achieves the task of attractor switching. I conclude with a few forward-looking remarks on how the same model-based control approach might come to bear on problems in biology.

SeminarNeuroscience

Neural mechanisms of active avoidance behavior

Manuel Castro-Alamancos
University of Connecticut School of Medicine
Jan 23, 2022
ePoster

Knocking out co-active plasticity rules in neural networks reveals synapse type-specific contributions for learning and memory

Zoe Harrington, Basile Confavreux, Pedro Gonçalves, Jakob Macke, Tim Vogels

Bernstein Conference 2024

ePoster

Modeling spatial and temporal attractive and repulsive biases in perception

Stefan Glasauer, W. Medendorp, Michel-Ange Amorim

Bernstein Conference 2024

ePoster

Bayesian active learning for closed-loop synaptic characterization

COSYNE 2022

ePoster

Bayesian active learning for latent variable models of decision-making

COSYNE 2022

ePoster

How does the dorsal striatum contribute to active choice rejection?

COSYNE 2022

ePoster

Approximate inference through active computation accounts for human categorization behavior

Xiang Li, Luigi Acerbi, Wei Ji Ma

COSYNE 2023

ePoster

Neural mechanisms of stream formation during active listening in the ferret auditory cortex

Jules Lebert, Carla Griffiths, Joseph Sollini, Jennifer Bizley

COSYNE 2023

ePoster

An attractive manifold of retinotopic map in a network model explains presaccadic receptive field remapping

Xize Xu, Sachira Denagamage, Anirvan Nandy, Monika Jadi

COSYNE 2025

ePoster

A computational framework for decoding active sensing

Benjamin Cellini, Burak Boyacioglu, Stanley Stupski, Floris van Breugel

COSYNE 2025

ePoster

Deep reinforcement learning trains agents to track odor plumes with active sensing

Lawrence Jianqiao Hu, Elliott Abe, Harsha Gurnani, Daniel Sitonic, Floris van Breugel, Edgar Y. Walker, Bing Brunton

COSYNE 2025

ePoster

Effect of psychedelic serotonin receptor agonist on visual response dynamics during active sensation

Rolf Skyberg, Christopher Fields, Cristopher Niell

COSYNE 2025

ePoster

Motor cortical neuronal population dynamics during active movement are altered in parkinsonian nonhuman primates

Yuxiao Ning, Biswaranjan Mohanty, Noah Hjelle, Luke Johnson, Jing Wang, Jerrold Vitek Vitek

COSYNE 2025

ePoster

Active zone mechanisms underlying the functional differentiation of olfactory sensory neurons in Drosophila melanogaster

Namrata Acharya, Nadine Ehmann, Robert J. Kittel

FENS Forum 2024

ePoster

Active tool-use training in near and far distances does not change time perception in peripersonal or far space

Amir Jahanian Najafabadi, Christoph Kayser

FENS Forum 2024

ePoster

Adinazolam, a benzodiazepine-type new psychoactive substance, produces reinforcement and dependence in rodents

Youyoung Lee, Wun-A Kook, Audrey Lynn Donio, Choon Gon Jang

FENS Forum 2024

ePoster

AI-assisted annotation of rodent behaviors: Collaboration of the human observer and SmartAnnotator software through active learning

Lucas Noldus, Elsbeth van Dam, Loes Ottink, Ruud Tegelenbosch, Marcel van Gerven

FENS Forum 2024

ePoster

Cerebral blood flow and executive function changes in response to active and passive aerobic exercise

Alma Rahimidarabad, Azar Ayaz, Gianna Jeyarajan, Lian Buwadi, Matthew Heath

FENS Forum 2024

ePoster

DendroTweaks: An interactive approach for unraveling dendritic dynamics

Roman Makarov, Spyridon Chavlis, Panayiota Poirazi

FENS Forum 2024

ePoster

Development of pharmacologically active nanobodies targeting the mGlu5R-A2AR heteromer in psychosis

Laura Isabel Sarasola, Swarnali Roy, Glòria Salort, Aleix Quintana, Leonardo Pardo, Ross Cheloha, Francisco Ciruela

FENS Forum 2024

ePoster

Effects of chronic treatment with extracted active ingredients from Chinese traditional medicine formula: Yueju on alleviating depression in animal models

Sonata Suk-yu Yau, Kai Le, Ping Wang, Jiaqi Li, Can Huang, Jiasui Yu, Gang Chen

FENS Forum 2024

ePoster

Electrophysiological correlates of neuroactive steroids treatment in the perinatal focal cerebral ischemia model in immature rats

Iqra Bano, Viera Kutna, Hana Chodounska, Eva Kudova, Grygoriy Tsenov

FENS Forum 2024

ePoster

Elevated reactive aggression in forebrain-specific CCN2 knockout mice

Li-Jen Lee, Ho-Ching Chang, Chi-Hou Ng, Kuang-Yung Lee

FENS Forum 2024

ePoster

Exploring pupil dynamics in freely moving rats during active integration of vision and posture

Loredana Stoica Ghita, Lukas Hillisch, Jonathan R. Whitlock

FENS Forum 2024

ePoster

A fish-in-the-loop system to study the underlying mechanisms of active sensing

Emin Yusuf Aydin, Ismail Uyanik

FENS Forum 2024

ePoster

Goal-directed alpha power actively filters initial afferent activity in early visual cortices

Chen Li, Kieran S. Mohr, Simon P. Kelly, Manuel Gomez-Ramirez, Ian C. Fiebelkorn

FENS Forum 2024

ePoster

Interactive brain atlas curation and enhancement with Houdini and Python

Davide Bella, Alessandro Foni, Julian Budd, Judit Planas, Henry Markram, Armando Romani

FENS Forum 2024

ePoster

Long-term implantation and cortical stimulation with photoactive organic semiconductors in a rat model

Marta Nowakowska, Marie Jakešová, Robert Reimer, Tony Schmidt, Ludovico Migliaccio, Julia Fuchs, Silke Patz, Vedran Đerek, Susanne Scheruebel, Theresa Rienmüller, Rainer Schindl, Eric Głowacki, Muammer Üçal

FENS Forum 2024

ePoster

A loss of spiral ganglion neurons with an active ATOH1 enhancer alters hearing function

Kateryna Pysanenko, Mitra Tavakoli, Romana Bohuslavova, Josef Syka, Bernd Fritzsch, Gabriela Pavlinkova

FENS Forum 2024

ePoster

Maternal C-reactive protein is associated with white matter alterations in female offspring: A neuroimaging analysis from the FinnBrain Birth Cohort Study

Aaron Barron, Gerard O'Keeffe, Cathal McCarthy, Minna Lukkarinen, Harri Merisaari, Linnea Karlsson, Hasse Karlsson, Jetro Tuulari

FENS Forum 2024

ePoster

Mitochondrial fission regulates reactive astrocyte response to acute brain injury

Abdulla Chihab, Milica Jevtic, Felix Gaedke, Hiromi Sesaki, Elisa Motori, Matteo Bergami

FENS Forum 2024

ePoster

Can Wii modulate pseudoneglect? Improving visuospatial attention in healthy subjects by active video gaming

Fabrizio Di Giovanni, Giuditta Gambino, Lorenzo Pia, Giuseppe Ferraro, Filippo Brighina, Danila Di Majo, Tommaso Ciorli, Pierangelo Sardo, Giuseppe Giglia

FENS Forum 2024

ePoster

Movement initiation reveals a hyperactive direct pathway in a mouse model of dystonia

Filipa França de Barros, Marcelo Mendonça, Diogo Soares Melo, Susanne Knorr, Lisa Rauschenberger, Chi Wang Ip, Rui M Costa, Albino Oliveira-Maia, Joaquim Alves da Silva

FENS Forum 2024

ePoster

Neuronal encoding of active avoidance in the nucleus accumbens

Mehdi Sicre, Joshua Johansen

FENS Forum 2024

ePoster

Passive versus active novelty detection: How volition shapes olfactory representations in the medial temporal lobe

Eleonore Schiltz, Cardinaels Lara, Haesler Sebastian

FENS Forum 2024

ePoster

Photo-controlled release of bioactive molecules in the brain

Clémentine Bosch Bouju, Camille Ruffier, Emmanuel Ibarboure, Jean-Christophe Helbling, Maria-Florencia Angelo, Rémi Kinet, Benjamin Dehay, Sébastien Marais, Pierre Trifilieff, Nathan McClenaghan, Sébastien Lecommandoux

FENS Forum 2024

ePoster

Quenching mitochondrial reactive oxygen species in oligodendrocytes protects axonal function in aging and neuroinflammatory disease

Urvashi Dalvi, Juan Villar Vesga, Fiona Seitz, Henri Zanker, Richard Fairless, Sarah Williams, Juan Bolanos, Bruno Weber, Sarah Mundt, Aiman Saab

FENS Forum 2024

ePoster

Quick & accurate neuron population quantification: An interactive, deep-learning accelerated method for neuron population quantification in mice brains

Roberto Leiras, Nicklas Boserup, Raghavendra Selvan, Stephan Dietrich, Ole Kiehn

FENS Forum 2024

ePoster

Reactive glia in culture boosts neurosphere formation by co-cultured non-reactive glia

Víctor Álvaro, Dulce María Arzate, Ana Victoria Prádanos-Senén, Marta Menéndez, Christophe Heinrich, Magdalena Götz, Sergio Gascón

FENS Forum 2024

ePoster

A REM-active basal ganglia circuit that regulates anxiety

Wei Ba, Mathieu Nollet, Xiao Yu, Chunyu Yin, Sara Wong, Andawei Miao, Esteban J Beckwith, Edward C Harding, Ying Ma, Raquel Yustos, William Wisden, Nicholas P Franks

FENS Forum 2024

ePoster

Self-supervised learning using Geometric Assessment-driven Topological Smoothing (GATS) for neuron tracing and Active Learning Environment (NeuroTrALE)

Nina Shamsi, Alec Xu, Michael Snyder, David Chavez, Aaron Rodriguez, Benjamin Roop, Adam Michaleas, Webster Guan, Kwanghun Chung, Laura Brattain, Lars Gjesteby

FENS Forum 2024