Donders Institute for Brain, Cognition and Behaviour
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Thesis defense Hassiba Beldjoud (Donders series 217)

11 May 2016

Promotor: prof. dr. B. Roozendaal

Role of the amygdala in chromatin remodeling effects underlying long-term memory

Whatever you remember as “very good” or “very bad” is because your amygdala was activated at the time of the event. In fact, emotional memories are known to be vivid and long lasting, and extensive evidence indicates that arousal-induced noradrenergic activation within the basolateral complex of the amygdala (BLA) facilitates the consolidation of memory in its many target regions. However, the neural mechanisms underlying this memory facilitation are largely unexplored.

A great deal of attention, during this last decade, has focused on the state of the chromatin within the cell nucleus in the regulation of gene expression, and histone post-translational modifications (PTMs) have been directly linked to this state.

In my study I examined whether noradrenergic activity within the BLA regulates memory consolidation by enabling chromatin modifications as well as protein related plasticity in the insular cortex a brain region involved in object recognition memory.

My work shed new light on the mechanism by which arousal modulates memory consolidation. I showed that chromatin remodelling in the insular cortex associated with the consolidation of object recognition memory requires BLA noradrenergic activity. Further, norepinephrine administration into the BLA facilitates object recognition memory and is associated with the expression of proteins associated with synaptic plasticity in the insular cortex.