Brain states

The brain adjusts its internal activity to direct visual and auditory attention and regulate responses to external stimuli. Appropriate endogenous activity may support normal cognition and behaviour, while its modulation can also produce dysfunction. Beginning with mathematical models of general anaesthesia, this talk examines how changes in noisy endogenous activity can fragment functional brain organization and account for loss of consciousness. Anaesthesia experiments in ferrets support the theoretical result. Further experimental examples are discussed to show how underlying internal noise

…signals are coordinated across the brain. Following this logic in rats performing a perceptual decision-making task, we recorded simultaneously from thousands of neurons across up to 20 brain regions at once. Here we report two internal signals wh

…Functional MRI allows coarse-grained brain activity comparison but lacks the resolution for understanding the emergence of whole-brain dynamics. With Zebrafish larvae, we can perform whole-brain single-neuron imaging, yet current cross-individual comparison methods are limited to sensory-driven paradigms. Thus, analyzing spontaneous brain activity across zebrafish larvae remains challenging. Presenting a novel approach, we employ a single Restricted Boltzmann M

Variable and intricate dynamics are core to cortical communication in the human brain. Electrical stimulations in intracranial EEG (iEEG) can help probe effective connectivity over time and brain states through the measurement of cortico-cortical evoked potentials (CCEPs).In 15 epilepsy patients undergoing iEEG for diagnostic reasons, we probed effective connectivity with single-pulse electrical stimulations (1ms, 3mA). For any given pair of iEEG contacts at shorter (<20mm) or longer (≥20mm) range, effective connectivity was expressed as a probability of observing a single-trial CCEP in one

…coupling modes that govern the brain dynamics. They mediate in an efficient and selective manner the communication in networks of cortical and subcortical areas to facilitate sensory processing, behavior, and perception. However, it is not clear yet if and how these two types of intrinsic coupling modes (ICMs) interact with each other. Here we investigate the relation between both coupling modes across different brain states. In accordance with our pr

Respiration shares strong functional links with the brain, influencing perception, emotions and cognition. In turn respiration is modulated by sensory stimuli, attention and vigilance states. To explore this intricate brain-body relationship, we performed intranasal pressure recordings in freely-moving mice paired with extracellular recordings in the CA1 region of the hippocampus to precisely detect Wake, non-REM and REM sleep epochs. We characterized different respiratory cycle features between vigilance states and uncovered unexpected breathing dynamics at transitions between them. To show h

In the analysis of neuro-electrophysiological recordings, recent developments have emphasized that as well as the commonly analyzed rhythmic or oscillatory activity, there is also prominent arrhythmic, or aperiodic activity. The distinction between periodic and aperiodic activity is important – methodologically because these two components can be conflated by common analysis approaches that do not explicitly consider the different forms of the data, and scientifically, as the two features have distinct interpretations in terms of the underlying circuit dynamics and physiological properties. In

This study aimed to delve into the role of the brainstem nucleus incertus (NI) as a structure involved in stress-response generation and its interactions with the ventral tegmental area (VTA), a key component of the brain's reward system. By tracing neural pathways using a retrograde viral vector, the NI-originating innervation of the VTA was confirmed within the midbrain of Sprague-Dawley rats. Immunohistochemical staining revealed that only a small percentage of NI neurons containing the relaxin-3 neuropeptide also project to the VTA, suggesting specialization of the connectivity between the

Variations in brain states and behavioral profiles clearly influence neuronal activity in the visual cortex[1,2]. However, the mechanisms behind these influences and their consequent effect on sensory encoding remain to be determined. Here, we address this issue by analyzing simultaneous recordings of spiking activity and local field potentials (LFPs) from visual and subcortical regions of (N = 25) awake mice viewing a naturalistic movie. Applying a hidden Markov model (HMM) to cortical LFPs, we consistently identified three stable states in each mouse: a high-frequency state (dominated by gam

Brain states are conventionally divided into wake, slow wave sleep (SWS) and rapid eye movement (REM) sleep based on distinct patterns of neural activity and muscle tone. However, recently available large-scale recordings indicate that this conventional division of brain states is insufficient to account for rich heterogeneity of neural dynamics on the global scale. During sleep, neural activity in some brain regions can exhibit awake signatures and vice versa [1,2]. While brain states provide the backdrop for any activity underlying behavioral functions, the spatiotemporal structure of multi-

Brain information processing is shaped by fluctuations in neuronal rhythmic activities, each defining distinctive brain states. Switches in brain states during wake-sleep cycle are described at the network level, by a neuronal population shift from active to oscillatory state. At the cellular level, neurons switch from tonic to burst. This switch is organized thanks to neuromodulators. They refer to signaling molecules that induce reversible changes in functional properties of neurons or synapses. Simultaneously, learning and memory are attributed to the ability of neurons to modify their conn