Brain stimulation is increasingly used to modulate neural activity, with applications ranging from basic neuroscience to clinical interventions in epilepsy, depression, Parkinson’s disease, and disorders of consciousness. Yet one major challenge remains: the same stimulation can sometimes produce different effects depending on when it is delivered. This suggests that the brain is not a passiveLire la suite « Phase-dependent brain stimulation: why dynamic functional connectivity matters »
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Detecting conscious perception in preverbal infants through Event Related Variability
A major challenge in developmental cognitive neuroscience is that preverbal infants cannot tell us what they perceive. This is especially difficult when studying conscious perception: how can we know whether an infant actually saw a stimulus, rather than merely processed it unconsciously? In this study, led by François Leroy and Ghislaine Dehaene at NeuroSpin, Saclay,Lire la suite « Detecting conscious perception in preverbal infants through Event Related Variability »
Optimal inhibitory-to-excitatory balance for flexible brain communication
Neural oscillations are among the brain’s main strategies for coordinating activity across cells and circuits. Different frequency bands are often associated with different computational roles: slower rhythms can support long-range coordination, while faster rhythms such as gamma are thought to help structure local processing and information transfer. Yet an important question remains open: how canLire la suite « Optimal inhibitory-to-excitatory balance for flexible brain communication »
40 Hz light stimulation restores brain dynamics and memory in an early Alzheimer’s disease mouse model
Alzheimer’s disease is often described in terms of its “hardware” damage: amyloid plaques, tau pathology, neuronal loss, and progressive structural degeneration. But before the brain is visibly damaged, its activity may already be changing. In this study, we asked whether early Alzheimer-like alterations could be detected not only in brain structure, but in brain dynamicsLire la suite « 40 Hz light stimulation restores brain dynamics and memory in an early Alzheimer’s disease mouse model »
What if all these different oscillations where entangled in a network of interdependence?
Linking neural activity to sensory, motor or cognitive processes is an ongoing goal in Neuroscience and articular attention has been devoted to the role of brain oscillations, analyzed by averaging over many trials in suitably designed tasks. Previous findings offer a glimpse of the complexity of the overall picture, but have also limitations. First, searchingLire la suite « What if all these different oscillations where entangled in a network of interdependence? »
Hippocampal gamma oscillatory complexity is not noise but reflects behavior and learning
Our FunSy paper on gamma oscillatory complexity in hippocampus is out in Nature Comms! The hippocampus and entorhinal cortex exhibit rich oscillatory patterns critical for cognitive functions. In the hippocampal region CA1, specific gamma-frequency oscillations, timed at different phases of the ongoing theta rhythm, are hypothesized to facilitate the integration of information from varied sources andLire la suite « Hippocampal gamma oscillatory complexity is not noise but reflects behavior and learning »
Perturbed Information Processing Complexity in Experimental Epilepsy
Usually we think that pathologies, as epilepsy, are associated to disruptions of the neural circuit mediating function. These disruptions certainly exist and are related e.g. to seizure events, which are rare and transient events. On the contrary, comorbidities, such as cognitive deficits, which often accompany epilepsies, constitute a basal state. This suggests that neural dynamics,Lire la suite « Perturbed Information Processing Complexity in Experimental Epilepsy »
Decomposing neural functions into information processing primitives?
We can easily name brain functions, and we are well informed about brain structure. However, it is not easy to bridge the gap between the two. Part of the problem is that simple circuit mechanisms do not directly give rise to high-level functions. Yet, they already implement simpler forms of information processing, a sort ofLire la suite « Decomposing neural functions into information processing primitives? »
Dynamic before time-averaged Functional Connectivity is destructured in Alzheimer’s Disease
Brain functions emerge from the coordinated dynamics of many brain regions. Dynamic functional connectivity (dFC) analyses are a key tool to describe such dynamic complexity and have been shown to be good predictors of cognitive performance. This is particularly true in the case of Alzheimer’s disease (AD) in which an impoverished dFC could indicate compromisedLire la suite « Dynamic before time-averaged Functional Connectivity is destructured in Alzheimer’s Disease »
From Event Related Potentials to Event Related Variability
In carefully designed experimental paradigms, cognitive scientists interpret the mean event-related potentials (ERP) in terms of cognitive operations. However, the huge signal variability from one trial to the next, questions the representability of such mean events. In our NeuroImage paper in collaboration with Ghislaine Dehaene (Neurospin, Paris-Saclay), we explored whether this variability is an unwantedLire la suite « From Event Related Potentials to Event Related Variability »