Neural correlates of consolidation in working memory.

Nelly Mainy (1, 2) , Philippe Kahane (3) , Lorella Minotti (3) , Dominique M. Hoffmann (3) , Olivier Bertrand (1, 2) , Jean-Philippe Lachaux (1, 2)

1 Processus mentaux et activation cérébrale
2 IFNL - IFR des neurosciences de Lyon
3 Neurosciences précliniques

Many of our daily activities rely on a brain system called working memory, which implements our ability to encode information for short-term maintenance, possible manipulation and retrieval. A recent intracranial study of patients performing a paradigmatic working memory task revealed that the maintenance of information involves a distributed network of oscillations in the gamma band (>40 Hz). Using a similar task, we focused on the encoding stage, and targeted a process referred to as short-term consolidation, which corresponds to the encoding of novel items in working memory. The paradigm was designed to manipulate the subjects' intention to encode: series of ten letters were presented, among which only five had to be remembered, as indicated by visual cues preceding, or following, each letter. During this task, we recorded the intracerebral EEG of nine epileptic patients implanted in mesiotemporal structures, perisylvian regions and prefrontal areas and used time-frequency analysis to search for neural activities simultaneous with the encoding of the letters into working memory. We found such activities in the form of increases of gamma band activity in a set of regions associated with the phonological loop, including the Broca area and the auditory cortex, and in the prefrontal cortex, the pre- and post-central gyri, the hippocampus and the fusiform gyrus.

Mots clés: Working memory; encoding; gamma band; intracranial EEG

Domaines: Neurosciences

Nelly Mainy, Philippe Kahane, Lorella Minotti, Dominique M. Hoffmann, Olivier Bertrand, et al.. Neural correlates of consolidation in working memory.. 2006. ⟨hal-00019455v1⟩