Neural ensembles

…renew and expand the Collaboratory on Neural Ensembles and Used Substances (NExUS). NExUS is a collaborative research program to decode how substance use experiences and addictive neurobehavioral states are represented in the brain at the level of cell populations. This funding opportunity seeks applications that propose systematic and scalable methods to identify, map, and analyze groups of neurons that respond to used substances. The goal is to create a comprehensive, multimodal database and use it to test hypotheses about h

…top-down reactivation of neural ensembles active during encoding, yet the neural mechanisms of such generative retrieval remain unknown. We formulate a biologically plausible hypothesis where transient cholinergic modulation, known to enhance backpropagated action potentials and trigger recall, initiates backward signals from sparse neurons discriminatively representing the cue to cortical areas encoding the trace. These signals

Memories are thought to be stored in synapses and retrieved through the reactivation of neural ensembles. However, neural representations exhibit significant dynamics even in stable environments, a phenomenon called representational drift. Theoretical studies suggest that multiple neural representations can correspond to a memory, with post-learning exploration of these representation solutions driving drift. However, the functional implications of drift-explored representations versus those initially learned remain poorly understood. Here we show that drift uncovers robust, sparsely engaged r

Understanding how the brain encodes movements is vital for motor control. Research suggests that this involves comparing proprioceptive inputs from the body with an internal model of expected movement. When these signals match, vestibular signals---which would otherwise stabilize the head against movements---are suppressed, allowing voluntary movement to occur. This mechanism implies that integrating proprioceptive and vestibular inputs is crucial for effective coordination. While previous studies indicate the involvement of multiple brain areas, with the PIVC at the forefront, the mechanisms

…spike-rate and spike-timing codes in neural ensembles from six visual areas during natural video presentations.

…The neural valence system is a network of interconnected brain regions that integrates downward sensory stimuli with upward signals reflecting the current physiological state

The coordinated recruitment of neural ensembles is thought to underlie behaviourally relevant information processing in the brain. These ensembles are temporally dynamic with individual neurons flexibly recruited into functional groups. In premotor cortex, intermingled neurons are activated during movement planning and execution but also in response to contextual cues, and reward. However, probing the behavioural role of these ensembles and understanding the circuit mechanisms underlying dynamic ensemble formation has been challenging due to the difficulty of flexibly manipulating individual c

…in the zebrafish forebrain, where ensembles of spatially organized neurons exhibit correlated activity. In the mammalian cortex, distinct classes of GABAergic neurons were show to play diverse roles in organizing su

…a fundamentally different approach to neural coding by using a novel method, SpikeShip, that is based on optimal transport theory. SpikeShip captures the information in all the relative spike-timing relations among neurons, without defining arbitrary features and counting spikes within wi

Neurons in the cortico-basal ganglia circuit become excessively synchronised at beta frequencies (15-35 Hz) in Parkinson’s disease. However, it is unclear how this synchronised firing evolves across the network. Beta synchrony has often been assumed to emerge homogenously across the neurons within anatomical structures of the basal ganglia. However, it is possible that beta oscillations may emerge in a modular fashion within the neurons that make up an anatomical structure. We hypothesized that neurons in subregions of the basal ganglia preferentially reflect onset and offset of beta oscillati

…hippocampal replay, when hippocampal neural ensembles briefly reactivate a representation related to prior experience, has been proposed to critically contribute to these memory-related processes. However, it remains unclear whether awake replay contributes to memory function by promoting the storage of past experiences, facilitating planning based on evaluation of those experiences, or both. We designed a dynamic spatial task that promotes replay befo