Cortical activity

Global excitatory activity patterns across the dorsal cortex are reorganized when mice perform perceptual decision-making tasks that involve different underlying computations and vary in complexity. However, the circuit mechanisms enabling such large-scale activity reorganization remain unknown. An interesting possibility is that they depend on neuromodulatory input to the cortex. In particular, cholinergic neurons in the basal forebrain project widely across cortical areas while exhibiting topographical and functional heterogeneity. They are therefore well equipped to serve as an orchestrator

…between complex behaviors and the activity of many simultaneously recorded neurons. While latent variable models can successfully extract low-dimensional embeddings from such recordings, using them to generate realistic spiking data, especially in a behavior-dependent manner, still poses a challenge. Here, we present Latent Diffusion for Neural Spiking data (LDNS), a diffusion-based generative model with a low-dimensional latent space: LDNS employs an autoencoder with structured state-space (S4) layers to pro

…9 and 21, to detect pain-related brain activity reflecting the inflammatory and non-inflammatory phases of this model. MRI scans were conducted before and 24 hours after the M

…the spatio-temporal dynamics of cortical activity requires novel measurement and analysis methodologies. We recorded broadband local field potential (LFP) across the whole neocortex in freely behaving rats using high-density flexible surface and translaminar arrays using active transistors. 3D tracking and spatio-spectral analysis of recordings over long sessions enabled automatic and accurate brain and behavioral

…While EEG measurements have found a subcortically evoked early neural activity to this speech-FFR, MEG studies have recently emphasized involvement of cortical sources as well. Here, we focused on disentangling the sources of the neural response at the fundamental frequency of speech using EEG-based source localization. We theref

Cortical activity is characterized by oscillatory dynamics at many scales. To capture such dynamics in a computational model and elucidate on its putative functional roles, we simulated recurrent networks consisting of coupled damped harmonic oscillators (DHOs), so called HORNs. In HORNs, each DHO node represents the aggregate activity of a recurrently connected E-I circuit such as a cortical column. Mathematically, a DHO is given by a 2nd order ordinary differential equation with a single state variable x (amplitude) To model different intrinsic properties of an underlying E-I circuit's recur

…widefield, calcium imaging to measure cortical activity as mice learnt to discriminate two tactile stimuli. During learning of this goal-directed sensory-discrimination ta

…objectively using EEG to discriminate activity related to different surroundings.Three virtual reality environments were designed (1: no nature; 2-3: nature) to study 23 participants who were asked to sit still while recording their EEG signals. To identify changes in cortical activity in different environments, a two-tailed Wilcoxon rank-sum test was applied to each electrode to compare the spec

The human brain comprises about 86 billion neurons organized in well-defined spatial locations that define clusters of neurons (modules). Each cognitive and motor function is possible thanks to the correct interaction among them. The disruption, loss, or alteration of these connections can produce pathological conditions. To understand how the information is transmitted and computed, we need to investigate the communication among the different modules. Another essential feature to understand is how the electrophysiological signals are transmitted is the 3D spatial organization. Many studies ma

Li Zhaoping discusses how cortical activity supports visual perception and the role of saliency in directing attention and gaze.

The internal and external world is thought to be represented by distributed patterns of cortical activity. The emergence of these cortical representations over the course of development remains an unresolved question. In this talk, I share results from a series of recent studies combining theory and experiments in the cortex of the ferret, a species with a well-defined columnar organization and modular network of orientation-selective responses in visual cortex. I show that prior to the onset of structured sensory experience, endogenous mechanisms set up a highly organized cortical network str

Cortical activity is characterized by state-specific dynamics arising from the interplay between connectivity, cellular diversity, and intrinsic properties. During non-Rapid Eye Movement (NREM) sleep, cortical population activity alternates between periods of neuronal firing (“UP” states) and neuronal silence (“DOWN” states). Patterns of neuronal activity at DOWN-to-UP (DU) transitions have functional relevance beyond sleep: they are related to sensory coding during wakefulness and support homeostatic processes and memory consolidation. Despite this functional importance, the factors that orga

Cortical activity changes dramatically upon changes in behavioral state, such as between sleep versus wake (McGinley et al 2015). Though the mechanisms enabling these distinct modes of cortical operation remain largely unknown, inhibitory neurons (INs) have been suggested repeatedly as a regulator of behavioral-state dependent neocortical activity (Batista-Brito et al 2018, Cardin et al 2019, Bugeon et al 2021). Here we investigate how a unique subpopulation of long-range INs impact cortical states. These cells are defined by the co-expression of somatostatin (SST) and neuronal nitric oxide sy

…circuit-level adaptive regulation of cortical activity during macro-fluctuati

…We find three regimes of activity. For suitably low synaptic gain, regardless of the level of symmetry, there exists a unique stable fixed point. Using a cavity-like approach, we develop a quantitative theory that describes the statistics of the activity in this unique fixed point, and the conditions for its stability. Increasing the synaptic gain, the unique fixed point destabilizes, and the network exhibits

Spontaneous behavior in animals and humans shows a striking amount of variability both in the spatial domain (which actions to choose) and temporal domain (when to act). Concatenating actions into sequences and behavioral plans reveals the existence of a hierarchy of timescales ranging from hundreds of milliseconds to minutes. How do multiple timescales emerge from neural circuit dynamics? How do circuits modulate temporal responses to flexibly adapt to changing demands? In this talk, we will present recent results from experiments and theory suggesting a new computational mechanism generating

Spontaneous and sensory-evoked cortical activity is highly state-dependent, promoting the functional flexibility of cortical circuits underlying perception and cognition. Using neural recordings in combination with behavioral state monitoring, we find that arousal and motor activity have complementary roles in regulating local cortical operations, providing dynamic control of sensory encoding. These changes in encoding are linked to altered performance on perceptual tasks. Neuromodulators, such as acetylcholine, may regulate this state-dependent flexibility of cortical network function. We the

…Here we monitor the state of activity of the animal through videography of the face, including pupil and whisker movements, as well as walking, while also monitoring the ability of the animal to perform a difficult auditory or visual task. We find that the state of the animal is continuously changing and is never stable. The animal is constantly becoming more or less activat