Dopaminergic neurons promote hippocampal reactivation and spatial memory persistence.
We found that optogenetic burst stimulation of hippocampal dopaminergic fibers from midbrain neurons in mice exploring novel environments enhanced the reactivation of pyramidal cell assemblies during subsequent sleep/rest. When applied during spatial learning of new goal locations, dopaminergic photostimulation improved the later recall of neural representations of space and stabilized memory performance. These findings reveal that midbrain dopaminergic neurons promote hippocampal network dynamics associated with memory persistence.
This month Colin McNamara and colleagues report compelling evidence of how rewarding or novel experiences strengthen newly-encoded spatial memories. The hippocampus provides the brain with representations of space (J. O'Keefe and J. Dostrovsky, 1971) but newly-formed hippocampal representations may degrade with time unless stabilized by additional processes.
Dr. Stéphanie Trouche joins the Unit as an MRC Investigator Scientist. Stéphanie’s previous research has focused on the neural circuits underlying memory processes and has employed system-neuroscience approach combining behavioural, neuroanatomical and imaging tools. In September 2009, Stéphanie obtained her Ph.D. in Neuroscience at the University of Toulouse, France, where she examined the contribution of new hippocampal neurons to spatial memory processes.
Published online yesterday is the latest study from Dr. David Dupret and colleagues in Nature Neuroscience.