Neuronal Networks of Memory

We study the dynamics of interaction between brain areas related to memory encoding and acquisition. In particular we are interested in in the exchange of information between the hippocampus and the cerebral cortex. We have previously showed that communication between hippocampus and prefrontal cortex changes as a function of behavioral demands and learning. (Benchenane et al. Neuron 2010)

During ‘offline’ periods, this interaction continues to support memory consolidation, by memory trace reactivation, the replay of neural patterns that originated in previous experience. Sleep plays a specific role in memory consolidation Slow-Wave Sleep (SWS) has been associated with the consolidation of declarative memories. SWS is characterized by slow oscillations of cortical field potentials, with bouts of intense firing separated by intervals of sparse activity, reflecting the bistability of the cortical network.

At the same time, the hippocampus engages in a more regular activity pattern, punctuated by large irregular activity containing rapid bursts of cell activity (sharp waves). The two phenomena are tightly related Together with A. Peyrache and S. Wiener (Paris), we developed a novel measure for memory trace reactivation (Peyrache et al. Nature Neuroscience 2009).

We are currently augmenting our methodological toolbox to include optogenetics stimulation, next generation silicon probes, closed loop pattern detection, thanks to two collaborative EU funded projects “ENLIGHTENMENT” and “NEUROSEEKER”. This will allow us to take the analysis of the neural dynamics of memory at the next level, potentially towards the manipulation of single memories, by combined readout and induction of neural patterns.

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