Patterns of brain activity while awake can shape the formation of their neuron connections during sleep according to a study in Nature Neuroscience this week. Whether two neurons are simultaneously active in an awake animal can determine whether an association will be formed between these same two neurons while it is asleep.
Jozsef Csicsvari and colleagues studied rats whilst exploring their environment and during sleep and recorded the activity of neurons in their hippocampus, an area implicated in memory formation. Across pairs of cells, the authors looked for brief intervals in which both cells fired an action potential. They found that the firing rate correlations for pairs that fired together more frequently increased in the sleep period after exploration when compared to sleep before this exploring behaviour. The authors also looked at intervals in which only one of the two cells fired, and that activity of one cell alone decreased the firing rate correlations between pairs of neurons. Similar mechanisms for changes in synaptic strength have previously been studied in tissue culture, and this paper provides evidence the same effect occurs in live animals.
Jozsef Csicsvari (University of Oxford, UK)
Abstract available online.
(C) Nature Neuroscience
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