Calcium imaging

…of the same cells using 2-photon (2p) calcium imaging, identifying neurons b

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)

A pivotal challenge in computational neuroscience is identifying sub-populations of neurons that encode behavior, perception, and memory, across varying contexts such as task difficulty or temporal progression. Therefore, analysis tools that provide model interpretability, beyond prediction performance, are essential for studying neuronal population activity. We propose a novel approach conditional-STochastic Gates (c-STG) that combines predictive modeling with contextual feature selection. c-STG comprises two networks: a hypernetwork that maps contextual variables to probabilistic feature sel

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by deficits in episodic memory processing and spatial navigation. Especially, the egocentric neural representation of space, which is important for constructing an egocentric cognitive map, is essential for spatial navigation. However, how spatial navigation deficits relate to egocentric neural representation of space remains unclear. The retrosplenial cortex (RSC) is one of the regions affected by amyloidosis in the early stages of AD and is well known for its role in egocentric spatial representation. Specifically, it cont

Mapping and understanding the functional differences between neuron types is crucial for advancing our knowledge of neural circuits and brain function. However, classifying neuron types in vivo remains challenging due to the difficulty of collecting reliable labels and the complexity of deciphering how neuronal activity varies across different conditions and stimuli. Even when labeled data is available, it is often hard to identify subtle functional differences between neuron classes. To address these challenges, we introduce a novel spatiotemporal Transformer-based architecture that learns a

Psychedelics like psilocybin and ketamine have shown great potential in treating psychiatric disorders, often producing long-lasting effects after a single dose, yet their underlying neural mechanisms remain poorly understood. Since one of the most consistent features of the psychedelic experience is the alteration in perception, this study aimed to investigate how acute doses of psychedelics influence perceptual integration. We used a free-response perceptual integration task in mice, alongside brain-wide mapping of drug-responsive populations using activity-dependent gene expression and calc

…We performed calcium imaging in CA1 place cells using a new Uncertain Reward virtual reality Task (URTask), in which mice run along a linear track and

Activity of sensory neurons is driven not only by stimuli but also by the behavior of the animal. For example, in the primary visual cortex (V1) of a mouse, the gain of sensory responses is modulated by the speed of movement [1]. On average, the response strength increases with running speed - this effect is prominent and systematic. Individual neurons can, however, reveal distinctive patterns of gain modulation. This diversity raises questions about how nuanced the impact of behavior on sensory coding is, whether it is limited to coarse gain changes, and what its computational function might

…novel methods, such as optogenetics, calcium imaging or DREADDs, have revolutionized rodent research, but are not yet widely used in avian research. This is in part due to the fact that these methods rely on the introduction of genetic information for artificial ion channels or sensors. In the absence of transgenic

Air pollution is a significant threat to human health and it is estimated that globally 8.9 million deaths happen because of it. A link between urban particulate matter exposure and an increased risk of neurodegenerative disease has already been identified. For this reason, I used wild-type hiPSCs to set up a 2D differentiation protocol of about 70 days. Cultures were untreated or treated with two doses of manganese, 1 μM and 20 μM, chosen in relation to scientific literature and after a MTS viability assay. Treatments started from day 40 until the end of differentiation (intermediate time poi

…Using calcium imaging of neurons and astrocytes in the APP/PS1 double transgenic Alzheimer’s disease mouse model, we investigated behavioural and cellular responses to repetitive visual stimuli, in comparison with littermate wild type (WT) mice.We collected data from 32 female

…developed for electrophysiological or imaging studies in head-fixed mice, there remains a scarcity of tasks incorporating neurophysiological recordings within a more ecologically realistic setting involving freely moving animals. This study introduces a tactile discrimination task for freely moving mice, integrating electrophysiology and calcium imaging with cellular resolution. In this go/no-go paradigm, mice learn to discrimin

…Furthermore, using calcium imaging, we confirmed that BG activati

A century ago, Kolmer and Agduhr identified ciliated neurons in the spinal cord that contact cerebrospinal fluid (CSF) across vertebrate species. These neurons, called spinal CSF-contacting neurons (CSF-cNs), modulate locomotion and posture by detecting mechanical and chemical cues from the CSF. However, the mechanisms by which CSF-cNs detect and respond to CSF changes are unknown. In this study, we investigate whether CSF-cNs in larval zebrafish can detect and respond to pathological CSF changes induced by a ventricular injection of Streptococcus pneumoniae (S. pneumoniae), the major pathogen

The suprachiasmatic nucleus (SCN) is the central circadian clock, governing physiological processes through its output to the subparaventricular zone (SPZ). We investigated functional synaptic connectivity between the SCN and the SPZ neurons in mouse brain slices and we studied the effects of peptides expressed in the SCN on the SPZ neurons. Photostimulation of SCN neuromedin-S (NMS) neurons or the vasoactive intestinal peptide (VIP) neurons induced opto-evoked inhibitory post-synaptic currents (oIPSCs) in 60% and 50% of recorded SPZ neurons, respectively. These responses were mediated by GABA

The traditional method in the development of drugs for neurodegenerative diseases, such as Alzheimer's or Parkinson's disease, necessitates the use of various animal models to assess complex behavioral changes. This process is not only time-consuming but also prone to misjudgments due to interspecies behavioral differences. In contrast, neural activity data gathered by head-mounted microscopy platforms represent integrated information that is relatively straightforward to interpret and exhibits low variability between species. This makes it an excellent resource for the development of correspo

The prefrontal cortex plays a key role in the representation of cognitive parameters, including task-relevant sensory cues, action selection and context. However, the contribution of GABAergic inhibitory interneuron types to the representation of these task features in active cell assemblies and their formation is incompletely understood. Here we focus specifically on parvalbumin (PVIs) and somatostatin (SOMIs) expressing interneurons within the prelimbic cortex (PL) of mice, as these interneuron types have been described to be involved in context encoding.We designed a contextual-auditory sti

A fundamental property of neurons in the primary visual cortex is their preference for orientation of edges that is invariant under contrast changes. We designed a synthetic hybrid neural circuit to study the emergence of orientation selectivity under different thalamo-cortical connection schemes. To this end, a computational model of the retino-thalamic pathway was combined with an in-vitro model of cortical input layer 4. The latter was either a primary culture of cortical neurons or an acute horizontal brain slice of primary visual cortex. The two stages were interfaced optogenetically by e

In environments rich with complex multisensory stimuli, flexible and effective behaviors rely on our ability to transfer learned associations across sensory modalities. Here, we explored the intertwined cortical representations of whisker and visual sensations in mice, focusing on their role in cross-modal transfer learning. Mice trained to differentiate between the stimulations of two vertically-aligned whiskers could seamlessly transfer this learned behavior to distinguish between two visual stimuli based on their vertical positioning. Generalization was achieved only when the spatial reward

Current neuromodulation strategies mainly rely on pharmaceutical interventions, with limited efficiency over time in chronic progressive neurodegenerative disorders. Alternate therapeutical approaches include electric neuromodulation like deep brain stimulation for Parkinson’s disease. Nowadays, a variety of neural prostheses has been successfully developed to restore damaged/lost neural functions such as the ability to communicate in a fully paralyzed patient, or to walk in cases of partial spinal lesions. However, despite proven therapeutic benefits, most available neural implants mainly rel

Animals encounter several dangerous situations during their lives, in response to which appropriate defensive responses are essential for survival. The selection of a proper defensive response to cope with each dangerous encounter relies not only on the recognition of specific threat characteristics and its context, but also on the detection of features shared by different threats. With a novel paradigm that exposes mice to multiple threatening situations, we recently demonstrated that neuronal populations in the dorsomedial prefrontal cortex (dmPFC) encode both a general danger state and spec

…Here we combine functional calcium imaging with ultrastructural circuit reconstruction, using a visual motion accumulation task in larval zebrafish. Using conne

…(“birthdated neurons”), and used calcium imaging, optogenetics, chemogenetics, in association with multiple hippocampus-dependent learning tasks to investigate their contribution to memory engrams over time

Calcium is a key intracellular messenger that regulates many vital cellular processes. Calcium signals in oligodendrocytes, the myelinating glia of the CNS, are known to translate environmental information to cellular processes such as proliferation, differentiation and myelination. Myelination is an adaptive process that depends on neuronal activity. We recently demonstrated that neuronal activity in vivo enhances remyelination in demyelinated lesions (Ortiz et al., 2019, JCI Insight). Here, we investigate whether calcium singal in oligodendroglia play a role in remyelination and whether beha