physiology

Padraig Gleeson

The successful applicant will contribute to the goals of the OpenWorm project, to create a cell by cell model of the nematode C. elegans incorporating its full neuronal network and a 3D body/environment simulation. The role will involve contributing to existing and creating new software packages which facilitate the goals of the OpenWorm project. It will also involve carrying out research into the physiology, anatomy and behaviour of C. elegans, to ensure the simulations are biologically realistic. Code will be open source from the start and active interaction with the community of researchers in this area will be required.

Consciousness at the edge of chaos

Over the last 20 years, neuroimaging and electrophysiology techniques have become central to understanding the mechanisms that accompany loss and recovery of consciousness. Much of this research is performed in the context of healthy individuals with neurotypical brain dynamics. Yet, a true understanding of how consciousness emerges from the joint action of neurons has to account for how severely pathological brains, often showing phenotypes typical of unconsciousness, can nonetheless generate a subjective viewpoint. In this presentation, I will start from the context of Disorders of Consciousness and will discuss recent work aimed at finding generalizable signatures of consciousness that are reliable across a spectrum of brain electrophysiological phenotypes focusing in particular on the notion of edge-of-chaos criticality.

Cellular Crosstalk in Brain Development, Evolution and Disease

Cellular crosstalk is an essential process during brain development and is influenced by numerous factors, including cell morphology, adhesion, the local extracellular matrix and secreted vesicles. Inspired by mutations associated with neurodevelopmental disorders, we focus on understanding the role of extracellular mechanisms essential for the proper development of the human brain. Therefore, we combine 2D and 3D in vitro human models to better understand the molecular and cellular mechanisms involved in progenitor proliferation and fate, migration and maturation of excitatory and inhibitory neurons during human brain development and tackle the causes of neurodevelopmental disorders.

Unpacking the role of the medial septum in spatial coding in the medial entorhinal cortex

Immune and metabolic regulation of sensorimotor physiology and repair

Investigating the Neurobiology and Neurophysiology of Psilocybin Using Drosophila melanogaster as a Model System

Fear learning induces synaptic potentiation between engram neurons in the rat lateral amygdala

Fear learning induces synaptic potentiation between engram neurons in the rat lateral amygdala. This study by Marios Abatis et al. demonstrates how fear conditioning strengthens synaptic connections between engram cells in the lateral amygdala, revealed through optogenetic identification of neuronal ensembles and electrophysiological measurements. The work provides crucial insights into memory formation mechanisms at the synaptic level, with implications for understanding anxiety disorders and developing targeted interventions. Presented by Dr. Kenneth Hayworth, this journal club will explore the paper's methodology linking engram cell reactivation with synaptic plasticity measurements, and discuss implications for memory decoding research.

Impact of High Fat Diet on Central Cardiac Circuits: When The Wanderer is Lost

Cardiac vagal motor drive originates in the brainstem's cardiac vagal motor neurons (CVNs). Despite well-established cardioinhibitory functions in health, our understanding of CVNs in disease is limited. There is a clear connection of cardiovascular regulation with metabolic and energy expenditure systems. Using high fat diet as a model, this talk will explore how metabolic dysfunction impacts the regulation of cardiac tissue through robust inhibition of CVNs. Specifically, it will present an often overlooked modality of inhibition, tonic gamma-aminobuytric acid (GABA) A-type neurotransmission using an array of techniques from single cell patch clamp electrophysiology to transgenic in vivo whole animal physiology. It also will highlight a unique interaction with the delta isoform of protein kinase C to facilitate GABA A-type receptor expression.

Examining dexterous motor control in children born with a below elbow deficiency

Circuit Mechanisms of Remote Memory

Memories of emotionally-salient events are long-lasting, guiding behavior from minutes to years after learning. The prelimbic cortex (PL) is required for fear memory retrieval across time and is densely interconnected with many subcortical and cortical areas involved in recent and remote memory recall, including the temporal association area (TeA). While the behavioral expression of a memory may remain constant over time, the neural activity mediating memory-guided behavior is dynamic. In PL, different neurons underlie recent and remote memory retrieval and remote memory-encoding neurons have preferential functional connectivity with cortical association areas, including TeA. TeA plays a preferential role in remote compared to recent memory retrieval, yet how TeA circuits drive remote memory retrieval remains poorly understood. Here we used a combination of activity-dependent neuronal tagging, viral circuit mapping and miniscope imaging to investigate the role of the PL-TeA circuit in fear memory retrieval across time in mice. We show that PL memory ensembles recruit PL-TeA neurons across time, and that PL-TeA neurons have enhanced encoding of salient cues and behaviors at remote timepoints. This recruitment depends upon ongoing synaptic activity in the learning-activated PL ensemble. Our results reveal a novel circuit encoding remote memory and provide insight into the principles of memory circuit reorganization across time.

Mouse Motor Cortex Circuits and Roles in Oromanual Behavior

I’m interested in structure-function relationships in neural circuits and behavior, with a focus on motor and somatosensory areas of the mouse’s cortex involved in controlling forelimb movements. In one line of investigation, we take a bottom-up, cellularly oriented approach and use optogenetics, electrophysiology, and related slice-based methods to dissect cell-type-specific circuits of corticospinal and other neurons in forelimb motor cortex. In another, we take a top-down ethologically oriented approach and analyze the kinematics and cortical correlates of “oromanual” dexterity as mice handle food. I'll discuss recent progress on both fronts.

Metabolic-functional coupling of parvalbmunin-positive GABAergic interneurons in the injured and epileptic brain

Parvalbumin-positive GABAergic interneurons (PV-INs) provide inhibitory control of excitatory neuron activity, coordinate circuit function, and regulate behavior and cognition. PV-INs are uniquely susceptible to loss and dysfunction in traumatic brain injury (TBI) and epilepsy but the cause of this susceptibility is unknown. One hypothesis is that PV-INs use specialized metabolic systems to support their high-frequency action potential firing and that metabolic stress disrupts these systems, leading to their dysfunction and loss. Metabolism-based therapies can restore PV-IN function after injury in preclinical TBI models. Based on these findings, we hypothesize that (1) PV-INs are highly metabolically specialized, (2) these specializations are lost after TBI, and (3) restoring PV-IN metabolic specializations can improve PV-IN function as well as TBI-related outcomes. Using novel single-cell approaches, we can now quantify cell-type-specific metabolism in complex tissues to determine whether PV-IN metabolic dysfunction contributes to the pathophysiology of TBI.

The role of mitopohagy in neuronal physiology

Combined electrophysiological and optical recording of multi-scale neural circuit dynamics

This webinar will showcase new approaches for electrophysiological recordings using our silicon neural probes and surface arrays combined with diverse optical methods such as wide-field or 2-photon imaging, fiber photometry, and optogenetic perturbations in awake, behaving mice. Multi-modal recording of single units and local field potentials across cortex, hippocampus and thalamus alongside calcium activity via GCaMP6F in cortical neurons in triple-transgenic animals or in hippocampal astrocytes via viral transduction are brought to bear to reveal hitherto inaccessible and under-appreciated aspects of coordinated dynamics in the brain.

Evolution of convulsive therapy from electroconvulsive therapy to Magnetic Seizure Therapy; Interventional Neuropsychiatry

In April, we will host Nolan Williams and Mustafa Husain. Be prepared to embark on a journey from early brain stimulation with ECT to state-of-the art TMS protocols and magnetic seizure therapy! The talks will be held on Thursday, April 25th at noon ET / 6PM CET. Nolan Williams, MD, is an associate professor of Psychiatry and Behavioral Science at Stanford University. He developed the SAINT protocol, which is the first FDA-cleared non-invasive, rapid-acting neuromodulation treatment for treatment-resistant depression. Mustafa Husain, MD, is an adjunct professor of Psychiatry and Behavioral Sciences at Duke University and a professor of Psychiatry and Neurology at UT Southwestern Medical Center, Dallas. He will tell us about “Evolution of convulsive therapy from electroconvulsive therapy to Magnetic Seizure Therapy”. As always, we will also get a glimpse at the “Person behind the science”. Please register va talks.stimulatingbrains.org to receive the (free) Zoom link, subscribe to our newsletter, or follow us on Twitter/X for further updates!

Cell-type-specific plasticity shapes neocortical dynamics for motor learning

How do cortical circuits acquire new dynamics that drive learned movements? This webinar will focus on mouse premotor cortex in relation to learned lick-timing and explore high-density electrophysiology using our silicon neural probes alongside region and cell-type-specific acute genetic manipulations of proteins required for synaptic plasticity.

How are the epileptogenesis clocks ticking?

The epileptogenesis process is associated with large-scale changes in gene expression, which contribute to the remodelling of brain networks permanently altering excitability. About 80% of the protein coding genes are under the influence of the circadian rhythms. These are 24-hour endogenous rhythms that determine a large number of daily changes in physiology and behavior in our bodies. In the brain, the master clock regulates a large number of pathways that are important during epileptogenesis and established-epilepsy, such as neurotransmission, synaptic homeostasis, inflammation, blood-brain barrier among others. In-depth mapping of the molecular basis of circadian timing in the brain is key for a complete understanding of the cellular and molecular events connecting genes to phenotypes.

Currents of Hope: how noninvasive brain stimulation is reshaping modern psychiatric care; Adapting to diversity: Integrating variability in brain structure and function into personalized / closed-loop non-invasive brain stimulation for substance use disorders

In March we will focus on TMS and host Ghazaleh Soleimani and Colleen Hanlon. The talks will talk place on Thursday, March 28th at noon ET – please be aware that this means 5PM CET since Boston already switched to summer time! Ghazaleh Soleimani, PhD, is a postdoctoral fellow in Dr Hamed Ekhtiari’s lab at the University of Minnesota. She is also the executive director of the International Network of tES/TMS for Addiction Medicine (INTAM). She will discuss “Adapting to diversity: Integrating variability in brain structure and function into personalized / closed-loop non-invasive brain stimulation for substance use disorders”. Colleen Hanlon, PhD, currently serves as a Vice President of Medical Affairs for BrainsWay, a company specializing in medical devices for mental health, including TMS. Colleen previously worked at the Medical University of South Carolina and Wake Forest School of Medicine. She received the International Brain Stimulation Early Career Award in 2023. She will discuss “Currents of Hope: how noninvasive brain stimulation is reshaping modern psychiatric care”. As always, we will also get a glimpse at the “Person behind the science”. Please register va talks.stimulatingbrains.org to receive the (free) Zoom link, subscribe to our newsletter, or follow us on Twitter/X for further updates!

Novel approaches to non-invasive neuromodulation for neuropsychiatric disorders; Effects of deep brain stimulation on brain function in obsessive-compulsive disorder

On Thursday, February 29th, we will host Damiaan Denys and Andrada Neacsiu. The talks will be followed by a shared discussion. You can register via talks.stimulatingbrains.org to receive the (free) Zoom link!

Closed-loop deep brain stimulation as a neuroprosthetic of dopaminergic circuits – Current evidence and future opportunities; Spatial filtering to enhance signal processing in invasive neurophysiology

On Thursday February 15th, we will host Victoria Peterson and Julian Neumann. Victoria will tell us about “Spatial filtering to enhance signal processing in invasive neurophysiology”. Besides his scientific presentation on “Closed-loop deep brain stimulation as a neuroprosthetic of dopaminergic circuits – Current evidence and future opportunities”, Julian will give us a glimpse at the person behind the science. The talks will be followed by a shared discussion. Note: The talks will exceptionally be held at 10 ET / 4PM CET. You can register via talks.stimulatingbrains.org to receive the (free) Zoom link!

Gut/Body interactions in health and disease

The adult intestine is a major barrier epithelium and coordinator of multi-organ functions. Stem cells constantly repair the intestinal epithelium by adjusting their proliferation and differentiation to tissue intrinsic as well as micro- and macro-environmental signals. How these signals integrate to control intestinal and whole-body homeostasis is largely unknown. Addressing this gap in knowledge is central to an improved understanding of intestinal pathophysiology and its systemic consequences. Combining Drosophila and mammalian model systems my laboratory has discovered fundamental mechanisms driving intestinal regeneration and tumourigenesis and outlined complex inter-organ signaling regulating health and disease. During my talk, I will discuss inter-related areas of research from my lab, including:1- Interactions between the intestine and its microenvironment influencing intestinal regeneration and tumourigenesis. 2- Long-range signals from the intestine impacting whole-body in health and disease.

State-of-the-Art Spike Sorting with SpikeInterface

This webinar will focus on spike sorting analysis with SpikeInterface, an open-source framework for the analysis of extracellular electrophysiology data. After a brief introduction of the project (~30 mins) highlighting the basics of the SpikeInterface software and advanced features (e.g., data compression, quality metrics, drift correction, cloud visualization), we will have an extensive hands-on tutorial (~90 mins) showing how to use SpikeInterface in a real-world scenario. After attending the webinar, you will: (1) have a global overview of the different steps involved in a processing pipeline; (2) know how to write a complete analysis pipeline with SpikeInterface.

Consolidation of remote contextual memory in the neocortical memory engram

Recent studies identified memory engram neurons, a neuronal population that is recruited by initial learning and is reactivated during memory recall.  Memory engram neurons are connected to one another through memory engram synapses in a distributed network of brain areas.  Our central hypothesis is that an associative memory is encoded and consolidated by selective strengthening of engram synapses.  We are testing this hypothesis, using a combination of engram cell labeling, optogenetic/chemogenetic, electrophysiological, and virus tracing approaches in rodent models of contextual fear conditioning.  In this talk, I will discuss our findings on how synaptic plasticity in memory engram synapses contributes to the acquisition and consolidation of contextual fear memory in a distributed network of the amygdala, hippocampus, and neocortex.

Rodents to Investigate the Neural Basis of Audiovisual Temporal Processing and Perception

To form a coherent perception of the world around us, we are constantly processing and integrating sensory information from multiple modalities. In fact, when auditory and visual stimuli occur within ~100 ms of each other, individuals tend to perceive the stimuli as a single event, even though they occurred separately. In recent years, our lab, and others, have developed rat models of audiovisual temporal perception using behavioural tasks such as temporal order judgments (TOJs) and synchrony judgments (SJs). While these rodent models demonstrate metrics that are consistent with humans (e.g., perceived simultaneity, temporal acuity), we have sought to confirm whether rodents demonstrate the hallmarks of audiovisual temporal perception, such as predictable shifts in their perception based on experience and sensitivity to alterations in neurochemistry. Ultimately, our findings indicate that rats serve as an excellent model to study the neural mechanisms underlying audiovisual temporal perception, which to date remains relativity unknown. Using our validated translational audiovisual behavioural tasks, in combination with optogenetics, neuropharmacology and in vivo electrophysiology, we aim to uncover the mechanisms by which inhibitory neurotransmission and top-down circuits finely control ones’ perception. This research will significantly advance our understanding of the neuronal circuitry underlying audiovisual temporal perception, and will be the first to establish the role of interneurons in regulating the synchronized neural activity that is thought to contribute to the precise binding of audiovisual stimuli.

Adaptive deep brain stimulation to treat gait disorders in Parkinson's disease; Personalized chronic adaptive deep brain stimulation outperforms conventional stimulation in Parkinson's disease

On Friday, August 31st we will host Stephanie Cernera & Doris Wang! Stephanie Cernera, PhD, is a postdoctoral research fellow in the Starr lab at University of California San Francisco. She will tell us about “Personalized chronic adaptive deep brain stimulation outperforms conventional stimulation in Parkinson’s Disease”. Doris Wang, MD, PhD, is a neurosurgeon and assistant professor at the University of California San Francisco. Apart from her scientific presentation about “Adaptive Deep Brain Stimulation to Treat Gait Disorders in Parkinson’s Disease”, she will give us a glimpse at the “Person behind the science”. The talks will be followed by a shared discussion. You can register via talks.stimulatingbrains.org to receive the (free) Zoom link!

Sleep deprivation and the human brain: from brain physiology to cognition”

Sleep strongly affects synaptic strength, making it critical for cognition, especially learning and memory formation. Whether and how sleep deprivation modulates human brain physiology and cognition is poorly understood. Here we examined how overnight sleep deprivation vs overnight sufficient sleep affects (a) cortical excitability, measured by transcranial magnetic stimulation, (b) inducibility of long-term potentiation (LTP)- and long-term depression (LTD)-like plasticity via transcranial direct current stimulation (tDCS), and (c) learning, memory, and attention. We found that sleep deprivation increases cortical excitability due to enhanced glutamate-related cortical facilitation and decreases and/or reverses GABAergic cortical inhibition. Furthermore, tDCS-induced LTP-like plasticity (anodal) abolishes while the inhibitory LTD-like plasticity (cathodal) converts to excitatory LTP-like plasticity under sleep deprivation. This is associated with increased EEG theta oscillations due to sleep pressure. Motor learning, behavioral counterparts of plasticity, and working memory and attention, which rely on cortical excitability, are also impaired during sleep deprivation. Our study indicates that upscaled brain excitability and altered plasticity, due to sleep deprivation, are associated with impaired cognitive performance. Besides showing how brain physiology and cognition undergo changes (from neurophysiology to higher-order cognition) under sleep pressure, the findings have implications for variability and optimal application of noninvasive brain stimulation.

The balanced brain: two-photon microscopy of inhibitory synapse formation

Coordination between excitatory and inhibitory synapses (providing positive and negative signals respectively) is required to ensure proper information processing in the brain. Many brain disorders, especially neurodevelopental disorders, are rooted in a specific disturbance of this coordination. In my research group we use a combination of two-photon microscopy and electrophisiology to examine how inhibitory synapses are fromed and how this formation is coordinated with nearby excitatroy synapses.

Distinct contributions of different anterior frontal regions to rule-guided decision-making in primates: complementary evidence from lesions, electrophysiology, and neurostimulation

Different prefrontal areas contribute in distinctly different ways to rule-guided behaviour in the context of a Wisconsin Card Sorting Test (WCST) analog for macaques. For example, causal evidence from circumscribed lesions in NHPs reveals that dorsolateral prefrontal cortex (dlPFC) is necessary to maintain a reinforced abstract rule in working memory, orbitofrontal cortex (OFC) is needed to rapidly update representations of rule value, and the anterior cingulate cortex (ACC) plays a key role in cognitive control and integrating information for correct and incorrect trials over recent outcomes. Moreover, recent lesion studies of frontopolar cortex (FPC) suggest it contributes to representing the relative value of unchosen alternatives, including rules. Yet we do not understand how these functional specializations relate to intrinsic neuronal activities nor the extent to which these neuronal activities differ between different prefrontal regions. After reviewing the aforementioned causal evidence I will present our new data from studies using multi-area multi-electrode recording techniques in NHPs to simultaneously record from four different prefrontal regions implicated in rule-guided behaviour. Multi-electrode micro-arrays (‘Utah arrays’) were chronically implanted in dlPFC, vlPFC, OFC, and FPC of two macaques, allowing us to simultaneously record single and multiunit activity, and local field potential (LFP), from all regions while the monkey performs the WCST analog. Rule-related neuronal activity was widespread in all areas recorded but it differed in degree and in timing between different areas. I will also present preliminary results from decoding analyses applied to rule-related neuronal activities both from individual clusters and also from population measures. These results confirm and help quantify dynamic task-related activities that differ between prefrontal regions. We also found task-related modulation of LFPs within beta and gamma bands in FPC. By combining this correlational recording methods with trial-specific causal interventions (electrical microstimulation) to FPC we could significantly enhance and impair animals performance in distinct task epochs in functionally relevant ways, further consistent with an emerging picture of regional functional specialization within a distributed framework of interacting and interconnected cortical regions.

My evolution in invasive human neurophysiology: From basal ganglia single units to chronic electrocorticography; Therapies orchestrated by patients' own rhythms

On Thursday, April 27th, we will host Hayriye Cagnan and Philip A. Starr. Hayriye Cagnan, PhD, is an associate professor at the MRC Brain Network Dynamics Unit and University of Oxford. She will tell us about “Therapies orchestrated by patients’ own rhythms”. Philip A. Starr, MD, PhD, is a neurosurgeon and professor of Neurological Surgery at the University of California San Francisco. Besides his scientific presentation on “My evolution in invasive human neurophysiology: from basal ganglia single units to chronic electrocorticography”, he will give us a glimpse at the person behind the science. The talks will be followed by a shared discussion. You can register via talks.stimulatingbrains.org to receive the (free) Zoom link!

More than a beast growing in a passive brain: excitation and inhibition drive epilepsy and glioma progression

Gliomas are brain tumors formed by networks of connected tumor cells, nested in and interacting with neuronal networks. Neuronal activities interfere with tumor growth and occurrence of seizures affects glioma prognosis, while the developing tumor triggers seizures in the infiltrated cortex. Oncometabolites produced by tumor cells and neurotransmitters affect both the generation of epileptic activities by neurons and the growth of glioma cells through synaptic-related mechanisms, involving both GABAergic / Chloride pathways and glutamatergic signaling. From a clinical sight, epilepsy occurrence is beneficial to glioma prognosis but growing tumors are epileptogenic, which constitutes a paradox. This lecture will review how inhibitory and excitatory signaling drives glioma growth and how epileptic and oncological processes are interfering, with a special focus on the human brain.

Crescent Loom: a flexible neurophysiology online simulation for teaching neuroethology

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

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.

Integrative Neuromodulation: from biomarker identification to optimizing neuromodulation

Why do we make decisions impulsively blinded in an emotionally rash moment? Or caught in the same repetitive suboptimal loop, avoiding fears or rushing headlong towards illusory rewards? These cognitive constructs underlying self-control and compulsive behaviours and their influence by emotion or incentives are relevant dimensionally across healthy individuals and hijacked across disorders of addiction, compulsivity and mood. My lab focuses on identifying theory-driven modifiable biomarkers focusing on these cognitive constructs with the ultimate goal to optimize and develop novel means of neuromodulation. Here I will provide a few examples of my group’s recent work to illustrate this approach. I describe a series of recent studies on intracranial physiology and acute stimulation focusing on risk taking and emotional processing. This talk highlights the subthalamic nucleus, a common target for deep brain stimulation for Parkinson’s disease and obsessive-compulsive disorder. I further describe recent translational work in non-invasive neuromodulation. Together these examples illustrate the approach of the lab highlighting modifiable biomarkers and optimizing neuromodulation.

Prox2+ and Runx3+ vagal sensory neurons regulate esophageal motility

Sensory neurons of the vagus nerve monitor distention and stretch in the gastrointestinal tract. We used genetically guided anatomical tracing, optogenetics and electrophysiology to identify and characterize two vagal sensory neuronal subtypes expressing Prox2 and Runx3. We show that these neuronal subtypes innervate the esophagus where they display regionalized innervation patterns. Electrophysiological analyses showed that they are both low threshold mechanoreceptors but possess different adaptation properties. Lastly, genetic ablation of Prox2 and Runx3 neurons demonstrated their essential roles for esophageal peristalsis and swallowing in freely behaving animals. Our work reveals the identity and function of the vagal neurons that provide mechanosensory feedback from the esophagus to the brain and could lead to better understanding and treatment of esophageal motility disorders.

Silences, Spikes and Bursts: Three-Part Knot of the Neural Code

When a neuron breaks silence, it can emit action potentials in a number of patterns. Some responses are so sudden and intense that electrophysiologists felt the need to single them out, labeling action potentials emitted at a particularly high frequency with a metonym – bursts. Is there more to bursts than a figure of speech? After all, sudden bouts of high-frequency firing are expected to occur whenever inputs surge. In this talk, I will discuss the implications of seeing the neural code as having three syllables: silences, spikes and bursts. In particular, I will describe recent theoretical and experimental results that implicate bursting in the implementation of top-down attention and the coordination of learning.

25 years of DBS beyond movement disorders: what challenges are we facing?; Directional DBS targeting of different nuclei in the thalamus for the treatment of pain

On Thursday, 23rd of February, we will host Veerle Visser-Vandewalle and Marie Krüger. Marie Krüger, MD, is is currently leading the stereotactic surgery unit in St. Gallen but is on her move to join the team at UCL / Queensquare London. She will discuss “Directional DBS targeting of different nuclei in the thalamus for the treatment of pain”. Veerle Visser-Vandewalle, MD, PhD, is the Head of the Department of Stereotactic and Functional Neurosurgery at University Hospital of Cologne. Beside his scientific presentation on “25 years of DBS beyond movement disorders: what challenges are we facing?”, she will also give us a glimpse at the “Person behind the science”. The talks will be followed by a shared discussion. You can register via talks.stimulatingbrains.org to receive the (free) Zoom link!

Love, death, and oxytocin: the challenges of mouse maternal care

Beta oscillations in the basal ganglia: Past, Present and Future; Oscillatory signatures of motor symptoms across movement disorders

On Wednesday, January 25th, at noon ET / 6PM CET, we will host Roxanne Lofredi and Hagai Bergman. Roxanne Lofredi, MD, is a research fellow in the Movement Disorders and Neuromodulation Unit at Charité Universitätsmedizin Berlin. Hagai Bergman, MD, PhD, is a Professor of Physiology in the Edmond and Lily Safra Center for Brain Research and Faculty of Medicine at the Hebrew University of Jerusalem, and is Simone and Bernard Guttman Chair in Brain Research. Beside his scientific presentation on “Beta oscillations in the basal ganglia: Past, Present and Future”, he will also give us a glimpse at the “Person behind the science”. The talks will be followed by a shared discussion. You can register via talks.stimulatingbrains.org to receive the (free) Zoom link!

Social attention & emotion: invasive neurophysiology & white matter pathway studies

‘The functional nano-architecture of axonal actin’

Bridging the gap from research to clinical decision making in epilepsy neuromodulation; How to become an integral part of the functional neurosurgery team as a radiologist

On Wednesday, November 30th, at noon ET / 6PM CET, we will host Alexandre Boutet and Erik H. Middlebrooks. Alexandre Boutet, MD, PhD, is a neuroradiology fellow at the University of Toronto, and will tell us about “How to become an integral part of the functional neurosurgery team as a radiologist”. Erik H. Middlebrooks, MD, is a Professor and Consultant of Neuroradiology and Neurosurgery and the Neuroradiology Program Director at Mayo Clinic. Beside his scientific presentation about “Bridging the Gap from Research to Clinical Decision Making in Epilepsy Neuromodulation”, he will also give us a glimpse at the “Person behind the science”. The talks will be followed by a shared discussion. You can register via talks.stimulatingbrains.org to receive the (free) Zoom link!

A premotor amodal clock for rhythmic tapping

We recorded and analyzed the population activity of hundreds of neurons in the medial premotor areas (MPC) of rhesus monkeys performing an isochronous tapping task guided by brief flashing stimuli or auditory tones. The animals showed a strong bias towards visual metronomes, with rhythmic tapping that was more precise and accurate than for auditory metronomes. The population dynamics in state space as well as the corresponding neural sequences shared the following properties across modalities: the circular dynamics of the neural trajectories and the neural sequences formed a regenerating loop for every produced interval, producing a relative time representation; the trajectories converged in similar state space at tapping times while the moving bumps restart at this point, resetting the beat-based clock; the tempo of the synchronized tapping was encoded by a combination of amplitude modulation and temporal scaling in the neural trajectories. In addition, the modality induced a displacement in the neural trajectories in auditory and visual subspaces without greatly altering time keeping mechanism. These results suggest that the interaction between the amodal internal representation of pulse within MPC and a modality specific external input generates a neural rhythmic clock whose dynamics define the temporal execution of tapping using auditory and visual metronomes.

It’s All About Motion: Functional organization of the multisensory motion system at 7T

The human middle temporal complex (hMT+) has a crucial biological relevance for the processing and detection of direction and speed of motion in visual stimuli. In both humans and monkeys, it has been extensively investigated in terms of its retinotopic properties and selectivity for direction of moving stimuli; however, only in recent years there has been an increasing interest in how neurons in MT encode the speed of motion. In this talk, I will explore the proposed mechanism of speed encoding questioning whether hMT+ neuronal populations encode the stimulus speed directly, or whether they separate motion into its spatial and temporal components. I will characterize how neuronal populations in hMT+ encode the speed of moving visual stimuli using electrocorticography ECoG and 7T fMRI. I will illustrate that the neuronal populations measured in hMT+ are not directly tuned to stimulus speed, but instead encode speed through separate and independent spatial and temporal frequency tuning. Finally, I will suggest that this mechanism may play a role in evaluating multisensory responses for visual, tactile and auditory stimuli in hMT+.

Hypothalamic episode generators underlying the neural control of fertility

The hypothalamus controls diverse homeostatic functions including fertility. Neural episode generators are required to drive the intermittent pulsatile and surge profiles of reproductive hormone secretion that control gonadal function. Studies in genetic mouse models have been fundamental in defining the neural circuits forming these central pattern generators and the full range of in vitro and in vivo optogenetic and chemogenetic methodologies have enabled investigation into their mechanism of action. The seminar will outline studies defining the hypothalamic “GnRH pulse generator network” and current understanding of its operation to drive pulsatile hormone secretion.

Neurosurgery for Mental Disorders: Challenging Mindsets; Combining Neuroimaging and Neurophysiology in Parkinson’s Disease

On Wednesday, October 26th, at noon ET / 6PM CET, we will host Kara Johnson, PhD, and Ludvic Zrinzo, MD PhD, for the inaugural session of our newly conceived talk series format entitled "Stimulating Brains". Kara A. Johnson, a postdoctoral fellow in Dr. Coralie de Hemptinne’s lab at the University of Florida, will present her work on “Combining imaging and neurophysiology in Parkinson’s disease”. Ludvic Zrinzo, Professor of functional neurosurgery and head of the University College London functional neurosurgery unit, will give us a glimpse at the “Person behind the science”, and give a talk on “Neurosurgery for mental disorders: challenging mindsets”. The talks will be followed by a shared discussion. You can register via talks.stimulatingbrains.org to receive the (free) Zoom link!

Pathophysiology of Thalamocortical and Corticofugal Systems in Parkinsonism

Baby steps to breakthroughs in precision health in neurodevelopmental disorders

Zero to Birth: How the Human Brain is Built

By the time a baby is born, its brain is equipped with tens of billions of intricately crafted neurons wired together to form a compact and breathtakingly efficient supercomputer. The book is meant to give a broad audience (i.e. non-neuroscientists) a sense of the step-by-step construction of a human brain as well as our current conceptual understanding of various processes involved. The book also hopes to highlight relevance of brain development to our growing understanding of cognitive and psychological variations and syndromes. The author will talk about the book including the many challenges and rewards involved in writing it.

High capacity electrophysiology: Lots more data, problematic analysis

Multi-level theory of neural representations in the era of large-scale neural recordings: Task-efficiency, representation geometry, and single neuron properties

A central goal in neuroscience is to understand how orchestrated computations in the brain arise from the properties of single neurons and networks of such neurons. Answering this question requires theoretical advances that shine light into the ‘black box’ of representations in neural circuits. In this talk, we will demonstrate theoretical approaches that help describe how cognitive and behavioral task implementations emerge from the structure in neural populations and from biologically plausible neural networks. First, we will introduce an analytic theory that connects geometric structures that arise from neural responses (i.e., neural manifolds) to the neural population’s efficiency in implementing a task. In particular, this theory describes a perceptron’s capacity for linearly classifying object categories based on the underlying neural manifolds’ structural properties. Next, we will describe how such methods can, in fact, open the ‘black box’ of distributed neuronal circuits in a range of experimental neural datasets. In particular, our method overcomes the limitations of traditional dimensionality reduction techniques, as it operates directly on the high-dimensional representations, rather than relying on low-dimensionality assumptions for visualization. Furthermore, this method allows for simultaneous multi-level analysis, by measuring geometric properties in neural population data, and estimating the amount of task information embedded in the same population. These geometric frameworks are general and can be used across different brain areas and task modalities, as demonstrated in the work of ours and others, ranging from the visual cortex to parietal cortex to hippocampus, and from calcium imaging to electrophysiology to fMRI datasets. Finally, we will discuss our recent efforts to fully extend this multi-level description of neural populations, by (1) investigating how single neuron properties shape the representation geometry in early sensory areas, and by (2) understanding how task-efficient neural manifolds emerge in biologically-constrained neural networks. By extending our mathematical toolkit for analyzing representations underlying complex neuronal networks, we hope to contribute to the long-term challenge of understanding the neuronal basis of tasks and behaviors.

New Insights into the Neural Machinery of Face Recognition

Robust multiband drift estimation in electrophysiology data

COSYNE 2023

Characterisation of in vivo synaptic and neuronal physiology in early and progressed amyloidopathy (APP/PS1 mouse model)

Chemogenetic manipulations of parvalbumin interneurons as an animal model of schizophrenia: implications on behavior and electrophysiology

Delineating IQ Motif and Sec7 Domain ArfGEF2, IQSEC2 in relevance to social deficits: From Physiology to Synapse

Distinct involvement of direct and indirect pathways from the dorsolateral and dorsomedial striatum in the pathophysiology of Huntington’s disease

Hidden targets of autism spectrum disorders: dissecting the pathophysiology of Wac in the ubiquitin-proteasome system

The Interplay of Lipopolysaccharide and Alpha-Synuclein to Model Gut-Brain Pathophysiology in Parkinson´s Disease

Investigation of multimodal processing in the mouse retrosplenial cortex: an electrophysiology study

Involvement of tRNA fragmentation in the pathophysiology of Huntington's disease

Late-life influence of childhood maltreatment on brain structure is mediated by parallel and sequential pathways of stress, immune, metabolic physiology

Novel field-effect-transistor nanoelectrode probes for active intracellular electrophysiology: a simulation study

Physiology and morphology of layer 5 neuron subtypes of anterior cingulate cortex in inflammatory pain

Physiology and physiopathology of cerebello-thalamic pathways in motor skill learning

Relationship between clock genes and Parkinson's pathophysiology in zebrafish

The role of Hippocampal VIP-expressing interneurons in the Pathophysiology of Temporal Lobe Epilepsy

Role of the tyrosine kinase Pyk2 in synaptic function and in the pathophysiology of Alzheimer's disease

Sculpted two-photon excitation of channelrhodopsins and genetically encoded voltage indicators for all-optical neurophysiology

Serotonergic and dopaminergic neurons in Dorsal Raphe Nucleus: from physiology to Parkinson’s Disease pathology

Simultaneous investigation of neuromodulatory systems during operant conditioning by fiber photometry and electrophysiology

Spinal Cav3.2 T-type channels impact on neuropathic pain: toward translating rodent findings to human pathophysiology

Transient motifs in neuronal dendrites revealed by nanopipette electrophysiology

TRPM8 and circadian physiology

Unravelling the role of the monoamine neuron system in the pathophysiology of SMA

Chemogenetic activation of thalamic subnuclei distinctively impairs sleep physiology

FENS Forum 2024

Combining electrophysiology, tissue clearing, and light sheet microscopy for an integrated approach towards brain circuit understanding

FENS Forum 2024

Disease-associated microglia-dependent and independent pathophysiology in spinal cord lesions in amyotrophic lateral sclerosis

FENS Forum 2024

Effects of VRK1 deficiency on the neurophysiology and behavior of zebrafish

FENS Forum 2024

Evaluating the spread of excitation with different types of optogenetic cochlear stimulation through computer simulations and in vivo electrophysiology

FENS Forum 2024

New insights into physiology of age-related cognitive disorders: The DNA repair protein ATR

FENS Forum 2024

Integrated electrophysiology and fiber photometry examination of the prefrontal cortex in the mouse model of implicit learning

FENS Forum 2024

Investigation of GABA transport and the GABA/Na+ relationship in human GAT1 using solid-supported membrane-based electrophysiology

FENS Forum 2024

Involvement of the hypothalamic A11 nucleus in the pathophysiology of Parkinsonian-like nociceptive disabilities

FENS Forum 2024

Maternal separation modifies the stress sensitivity, electrophysiology, and morphology of rat nucleus incertus neurons

FENS Forum 2024

MRI-visible superparamagnetic ultraflexible electrodes for precision electrophysiology

FENS Forum 2024

Navigating through the entorhinal cortex: Combining single-cell electrophysiology and RNA sequencing to advance our knowledge on the neuronal architecture

FENS Forum 2024

Neurophysiology of perceptual closure abilities in children with autism spectrum disorder and neurotypical control children

FENS Forum 2024

Next-generation electrophysiology for functional characterization of human neural organoids

FENS Forum 2024

3D organization of microglia in physiology and neurodegeneration

FENS Forum 2024

Patient-specific EEG simulation of focal and generalized epilepsy with a virtual human brain based on neurophysiology

FENS Forum 2024

The pyruvate dehydrogenase as a new potential therapeutic target in Parkinson’s disease pathophysiology

FENS Forum 2024