Somatostatin

Neural activity in the cortex exhibits a wide range of timescales, allowing animals to respond to rapidly changing sensory stimuli while maintaining information in working memory. Recent studies show how top-down inputs representing locomotive state modulates these timescales differently across visual areas in mice. In particular, the sign of correlations between speed and neural activity varies by region, highlighting the interplay between bottom-up sensory inputs, top-down pathways and connectivity motifs in shaping cortical dynamics. In addition, cortical circuits comprise a large diversity

Neural activity in the cortex exhibits a wide range of timescales, allowing animals to respond to rapidly changing sensory stimuli while maintaining information in working memory. The timescales of neural activity are not only affected by bottom-up sensory inputs, but also by top-down inputs originating from corticocortical and neuromodulatory pathways. In addition, cortical circuits comprise a large diversity of cell types connected in non-random ways, which are the subject of profound plasticity dynamics. Due to this complexity, understanding how top-down projections affect the timescales of

The basolateral amygdala (BLA) is increasingly recognized as a key regulator of depression and anxiety-like behaviors. However, the specific contribution of individual BLA neurons to these behaviors remains poorly understood. Building on our previous study, which demonstrated increased activity in glutamatergic BLA neurons in response to aversive stimuli and that enhancing inhibition in the BLA can alleviate depressive-like behaviors, we investigated the role of individual GABAergic neurons (BLAGABA) in depressive and anxiety-like phenotypes. Our findings indicate that BLAGABA neurons show dec

The processing of sensory information by the neocortex is at the heart of conscious perception and is known to involve a dynamic interaction between synaptically connected GABAergic inhibitory interneurons (INs) and excitatory principal neurons (PNs). One hypothesis is that sensory feature encoding in PNs is supported by different IN types performing specific functional roles. Here we address this hypothesis in the mouse thermal cortex. The thermal system is a fundamental pathway required for accurate object identification, pain perception and body temperature regulation and one that is highly

Hippocampal Interneurons are heavily myelinated but show differences in composition/distribution and myelin function. Contactin-2 (CNTN2 or TAG-1), an adhesion molecule of the immunoglobulin superfamily, expressed in glia and axons, organizes the juxtaparanodal region of myelinated fibers and clusters voltage-gated potassium channels under the myelin sheath. CNTN2 has a dynamic spatial and temporal expression and is implicated in migration during development as well as in neuropathology (multiple sclerosis, AD). We have shown that a significant population of hippocampal GABAergic interneurons

…Somatostatin (SOM) and Parvalbumin (PV) positive GABAergic neurons are two major classes of interneurons in the hippocampus, providing strong dendritic and peri-somatic inhibition to excitatory neurons, respectively. It is well known that exposure of mice to an enriched environment (EE) reliably increases performance on hippocampus-dependent learning and memory tasks. However, the mechanisms underlying the behavioral improvements an

…cells (Pyr), parvalbumin- (PV+), somatostatin- (Sst+), and vasoactive intestinal peptide- (VIP+) expressing interneurons, in processing information about familiar and novel social stimuli.We employed chemo/optogenetics alongside automated behavioral testing in Eco-HAB®, an RFID-based system for ecologically relevant assessment of social behavior in group-housed mice. This

Recently, research has focused extensively on the peripheral mechanisms that contribute to pain chronification, but our knowledge on the involvement of different brain regions remains limited. The Nucleus Accumbens (NAc) is a central hub for reward-related processes, with its interneurons having significant potential to control NAc output signals. However, their involvement in the chronification of pain has not been investigated until now.In this study, we performed patch-clamp recordings of cholinergic interneurons (ChIs) and GABAergic interneurons positive for parvalbumin (PV-GaIs) and somat

…long-range INs that co-express somatostatin (SST) and neuronal nitric oxide synthase (nNOS) (“SST/nNOS cells”), control patterns of synchronous neocortical activity and arousal states in mice. While the in-vivo function of SST/nNOS cells

…Moreover, Somatostatin (SST) expressing interneurons are involved in neuronal plasticity and are important in modulating cocaine-seeking behaviour in mice.We are testing the role of TrkB in Somatostatin(SST)-expressing neurons in the formation

The ventral hippocampus (vHPC) is a brain locus centrally involved in the control of stress and anxiety, with dysfunction of its interneuron network strongly implicated in clinical anxiety-related disorders. The vHPC is heavily innervated by neurons in the pontine tegmental, nucleus incertus (NI) – the primary source of the neuropeptide, relaxin-3 (RLN3), in the rat brain. Intriguingly, sustained activation of the RLN3 receptor, RXFP3, in the vHPC of rats increased anxiety and social avoidance [1], yet the precise underlying neuronal mechanisms remain unknown. Therefore, this study investigate

…expressing calretinin, calbindin, somatostatin and glutamate-decarboxylase (GAD) increased. We also observed that the major sources of these prospective GABAergic neurons

The hippocampus plays a pivotal role in the formation of episodic memories, facilitating spatial navigation and detection of novel stimuli. Within this structure, the dentate gyrus (DG) is crucial for discriminating novel from familiar content. Despite GABAergic inhibitory interneurons (INs) being increasingly recognized to participate to the hippocampal computation by controlling the activity of principal cells, the specific mechanisms by which they contribute to the encoding of episodic memories remain elusive. This study explores how interneurons (INs) representations of spatial context are

The loss of memories is the earliest and often most detrimental symptom in the course of Alzheimer’s disease (AD), the most common form of dementia. The loss of neuronal cells, which are assumed to carry mnemonic information, suggests itself to be the leading cause of memory loss. Besides, the question of alternative mechanisms has been raised. Our lab recently showed that an additional cell ensemble, so-called novelty-like cells, interfered with the engram and thus, impaired memory recall. This suggests a novel mechanism of memory impairment. However, the exact circuit that leads to the evoca

Rapid eye movement (REM, also called paradoxical) sleep correlates with enhanced cellular activity in region-specific thalamo-cortical circuits and subcortical structures including the hippocampus, midbrain or hypothalamus. This REM sleep specific neuronal activity is hypothesized to promote structural plasticity and provide a window for the consolidation of contextual and emotional memories previously acquired during wakefulness, yet the underlying mechanism remains unclear.Amongst the cortical structures, the activity of neurons located in the retrosplenial cortex (RSC) is increased during R

…Subset of these neurons contains somatostatin (SOM); these cells play crucial roles in neuroplasticity, learning and memory in many brain areas including the hippocampus, and are implicated in neuropsychiatric diseases and neurodegenerative disorders. Two main types of SOM-containing cells in area CA1 of the hippocampus are oriens-lacunosum-moleculare (OLM) and hippocampo-septal cells. These cell types show many similarities in their soma-dendritic architecture, but they have different axonal tar

The claustrum consists of the core and shell subregions. To investigate the involvement of GABAergic neurons in the circuitry in each subregion, we examined the distribution, neurochemical marker expression, and dendritic and axonal arborizations of claustral GABAergic neurons. Fluorescence in situ hybridization combined with immunofluorescence labeling revealed that approximately 10% of neuronal marker-positive cells expressed 67kDa-glutamic acid decarboxylase mRNA across the claustral subregions. Approximately 20%, 30%, and 10% of GABAergic neurons showed the immunoreactivity for parvalbumin

…are defined by the co-expression of somatostatin (SST) and neuronal nitric oxide sy

Cortical circuits process information by rich recurrent interactions between excitatory neurons and inhibitory interneurons. One of the prime functions of interneurons is to stabilize the circuit by feedback inhibition, but the level of specificity on which inhibitory feedback operates is not fully resolved. We hypothesized that inhibitory circuits could enable separate feedback control loops for different synaptic input streams, by means of specific feedback inhibition to different neuronal compartments. To investigate this hypothesis, we adopted an optimization approach. Leveraging recent ad

Sensory experience and perceptual learning changes receptive field properties of cortical pyramidal neurons possibly mediated by long-term potentiation (LTP) of synapses. We have previously shown in the mouse somatosensory cortex (S1) that sensory-driven LTP in layer (L) 2/3 pyramidal neurons is dependent on higher order thalamic feedback from the posteromedial nucleus (POm), which is thought to convey contextual information from various cortical regions integrated with sensory input. We have followed up on this work by dissecting the cortical microcircuitry that underlies this form of LTP

Neural codes, such as temporal codes (precisely timed spikes) and rate codes (instantaneous spike firing rates), are believed to be used in encoding sensory information into spike trains of cortical neurons. Temporal and rate codes co-exist in the spike train and such multiplexed neural code-carrying spike trains have been shown to be spatially synchronized in multiple neurons across different cortical layers during sensory information processing. Inhibition is suggested to promote such synchronization, but it is unclear whether distinct subtypes of interneurons make different contributions in

Inhibitory interneurons come in different classes and form intricate circuits. While our knowledge of these circuits has advanced substantially over the last decades, it is not fully understood how the structure of these circuits relates to their function. I will present some of our recent attempts to “understand” the structure of interneuron circuits by means of computational modeling. Surprisingly (at least for us), we found that prominent features of inhibitory circuitry can be accounted for by an optimisation for excitation-inhibition (E/I) balance. In particular, we find that such an opti

…plasticity in olfactory cortex- somatostatin (SST-INs), parvalbumin (PV-INs), and vasoactive intestin