Population coding of behavioral events in the median raphe circuit

Coding by transiently emerging co-active ensembles of neurons has long been a central tenet of neuroscience formulated in the influential assembly hypothesis. Accordingly, the animal’s actions can be predicted much more efficiently from the coordinated activity pattern of neurons than from the stimulus or event-locked spiking of single units. In contrast to cortical and hippocampal networks, assembly coding in subcortical modulatory circuits is almost fully unexplored. In this project, we aim to reveal and characterize the assembly code in the median raphe (MR), the source of ascending serotonergic neuromodulation of the limbic system. We expect to identify a fundamentally novel mode of neuromodulation whereby adaptive behavioral responses are controlled by the correlated activity of modulatory neuronal assemblies.