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 »
Archives de l’étiquette : FunSy
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 »
When neural manifolds are useful to repair signal artifacts
Electrophysiology recordings are frequently affected by artifacts (e.g., subject motion or eye movements), which reduces the number of available trials and affects the statistical power. When artifacts are unavoidable and data are scarce, signal reconstruction algorithms that allow for the retention of sufficient trials become crucial. In our paper published on Sensors, in collaboration withLire la suite « When neural manifolds are useful to repair signal artifacts »
Densely tied in space… but also for a sufficient time!
Functional interactions between brain regions or neurons have been described using features defined in network theory. For instance, the rich club phenomenon correspond to having high-degree nodes connected between them above chance-level. In our new Nature Physics paper we generalize this notion to dynamic networks. Indeed, in order for a certain spatial pattern in networkLire la suite « Densely tied in space… but also for a sufficient time! »
Graph-based features to capture the embodiment of adaptive behavior
The cerebellar cortex encodes sensorimotor adaptation during skilled locomotor behaviors, however the precise relationship between synaptic connectivity and behavior is unclear. In our recent Nature Communications paper (in collaboration with Philippe Isope’s group at INCI, Strasbourg), we studied synaptic connectivity between granule cells (GCs) and Purkinje cells (PCs) in murine acute cerebellar slices using photostimulationLire la suite « Graph-based features to capture the embodiment of adaptive behavior »
The speed and geometry of resting state dynamic Functional Connectivity
We are happy announcing that a diptych of publications on resting dynamic Functional Connectivity is finally out on NeuroImage! Functional Connectivity (FC) measured on resting state fMRI is dynamic and continually reconfiguring. However these variations are not necessarily very large and discrete state transitions are difficult (or questionable) to identify. Here we introduce a newLire la suite « The speed and geometry of resting state dynamic Functional Connectivity »
Uncoupling the roles of firing rate and spike bursts in shaping the gpe-stn beta band oscillations.
The excess of 15-30 Hz (β-band) oscillations in the basal ganglia is one of the key signatures of Parkinson’s disease (PD). The STN-GPe network is integral to generation and modulation of β band oscillations in basal ganglia. However, the role of changes in the firing rates and spike bursting of STN and GPe neurons in shaping theseLire la suite « Uncoupling the roles of firing rate and spike bursts in shaping the gpe-stn beta band oscillations. »
Computing hubs and states in the hippocampus?
In dominant views, a neuron becomes a functional hub because of its special position within a circuit. In our recently accepted paper on Science Advances, we find experimental evidence supporting a much more democratic view in which almost a majority of recorded single units could serve as hub at least for some time and forLire la suite « Computing hubs and states in the hippocampus? »
Homologous basal ganglia network models in physiological and parkinsonian conditions
The classical model of basal ganglia has been refined in recent years with discoveries of subpopulations within a nucleus and previously unknown projections. One such discovery is the presence of subpopulations of arkypallidal and prototypical neurons in external globus pallidus, which was previously considered to be a primarily homogeneous nucleus. Developing a computational model ofLire la suite « Homologous basal ganglia network models in physiological and parkinsonian conditions »
AD before plaques
Alzheimer’s disease (AD) is a neurodegenerative pathology commonly characterized by a progressive and irreversible deterioration of cognitive functions, especially memory. Although the etiology of AD remains unknown, a consensus has emerged on the amyloid hypothesis, which posits that increased production of soluble amyloid b (Ab) peptide induces neuronal network dysfunctions and cognitive deficits. In ourLire la suite « AD before plaques »