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Romain Goutagny’s and Demian Battaglia’s FunSy team @University of Strasbourg
Dynamic complexity as a resource for brain functional computations

Romain Goutagny

CNRS research scientist
Rodent electrophysiology and behavior, hippocampus, oscillations, memory…

Demian Battaglia

CNRS research scientist
Computational modelling, oscillations, network and information theory…

Taming (rather than ignoring) the complexity of neural dynamics

We consider micro-, meso- and macro-scale brain circuits as dynamical systems that collectively produce functional computations and, ultimately, cognition and behavior. Here, the keyword is “collectively”, and, briefly, we could say that “the whole is more (and different) than the sum of the parts”. Analogously, pathologies are usually interpreted in terms of damage to system’s parts (“hardware”), while they may, especially in early stages, build-up from alterations of system’s dynamics (“software”).

We combine data collection with state-of-the-art experimental techniques (R. Goutagny) with sophisticated analytical tools including machine-learning, information theory, network science and computational modeling (D. Battaglia), all conducted at different spatial and temporal scales, to dissect the potential cognitive algorithms mediated by neural oscillations and other neural dynamics patterns. The cross-fertilization between theory and experiments is central in our research. In our agnostic approaches, we try refraining from averaging over long times and many trials, as we believe that fluctuations are not mere noise, but that their spatiotemporal organization and non-linearities conveys rich information which can be revealed without a priori assumptions. We thus naturally focus on phenomena such as oscillatory bursting, cross-frequency coupling, dynamic functional connectivity and switching between states. We adapt our analysis and modelling approaches to very different types of neural signals, from single units and LFPs to brain-wide EEG and fMRI (human, NHP, rodent, cultures…).

We aim at understanding how coordinated neural dynamics mediate information processing relevant to behavior, memory and attention functions (with an election focus on hippocampal and cortical networks). We also aim at identifying how alterations of dynamics translate into functional impairments. The dream is to design interventions that would preserve/rescue function by “repairing dynamics” and functional connectivity.

Highlights

Oscillatory power and coherence are not stationary, but wildly fluctuate in intensity, frequency and phase. We isolate oscillatory events and show that they individually convey decodable information and that their coordination mediates routing and other primitive info-processing operations.

Brain rhythms and, particularly, hippocampal rhythms are nonlinearly interacting. Learning of a navigation target increases theta-gamma coupling more than it affects the two rhythms individually. Enhanced coordination may be a mechanism for enhanced behavioral and cognitive performance.

Functional networks, tracking coordination between neurons or local populations, evolves flexibly in time, in a way which is neither ordered, nor completely disordered. We develop multi-scale metrics of system’s reconfiguration which correlate with cognitive function (and its developmental or pathological changes).

Computational models are useful abstractions to probe (or reverse-engineer) circuit mechanisms, to engender new hypotheses and to extrapolate unexpected consequences of familiar scenarios. We use both spiking and mean-field models, from local micro-circuits up to whole virtual brains.

Science and news

Postdoc opening available immediately

We are currently inviting applications for a full-time postdoc position under the joint co-mentoring of Dr. Demian Battaglia and Dr. Romain Goutagny (University of Strasbourg, France; Functional System’s Dynamics team – FunSy, https://funsyteam.org). The position starts as soon as possible and can last up to two years. This job offer is funded by the French ANR « HippoComp » project, which focuses on…

Two gamma bands? Or two gamma complex ensembles?

In our newest preprint on BioRxiv, in collaboration with Alessandro Torcini and Matteo di Volo, we revisit a classic theory about the existence of two different gamma rhythms in the hippocampus CA1. We first deconstruct this theory, showing its insufficiency to account for the haphazard diversity of hippocampal gamma. We however reconstruct and rescue the…

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 network…

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 photostimulation…

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 new…

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 for…

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 our…

Theta-gamma coupling as « Eureka »?

Spatial reference memory in rodents represents a unique opportunity to study brain mechanisms responsible for encoding, storage and retrieval of a memory. Even though its reliance on hippocampal networks has long been established, the precise computations performed by different hippocampal subfields during spatial learning are still not clear. In our Cerebral Cortex paper, to study…


Now my own suspicion is that the universe brain is not only queerer than we suppose, but queerer than we can suppose.


J.B.S. Haldane, froM Possible Worlds and Other Papers (1927, with a small change 😉 )

About us

How to find us

We are located within the building of the Faculty of Psychology, at the ground floor (LNCA wing, to the right, end of the corridor, entering from Rue Goethe side).

LNCA – 12 rue Goethe, F-67000 STRASBOURG

Tramway lines C/E/F – stop « Université » – Bus line 2 (~15 min from central station) – Strasbourg Entzheim airport at ~40 min, high speed train to Paris CDG and Frankfurt / Main international hubs.