Relationship between network structure and activity dynamics in striatum

by Arvind Kumar (Bernstein Center Freiburg, Germany)

Friday 4 Oct 2013, 10:00 → 11:00 Europe/Stockholm

RB35

Striatum is the main input of the basal ganglia and therefore plays a crucial role in a variety of motor and cognitive tasks. Striatum is a purely inhibitory network that receives excitatory input from multiple areas in the cortex and thalamus. The output of the striatum constitute the two main pathways of the basal ganglia. Conveniently, the neurons that project to the direct (Go) and indirect (No-Go) pathways express D1 and D2 type dopamine receptors, respectively. In its simplest form striatum function can be reduced to setting up the balance of the D1 and D2 neurons to choose between Go and No-Go decisions. Recently, it has become clear that the D1 and D2 neurons differ in their passive integrative properties and mutual and recurrent connectivity. Interestingly, the D2 neurons inhibit D1 neurons more strongly. Moreover, the recurrent connectivity changes non-monotonically as a function of distance. I will discuss the consequence of spatial structure of connectivity between and within D1 and D2 neurons on the balance of the direct and indirect pathways. I will show that striatum can exploit different features of cortical input and recurrent circuitry to change the relative activity strength between the direct and indirect pathways to initiate the decision making process. In addition, the non-monotonic spatial connectivity renders the striatum ability to flexibly switch among asynchronous-irregular, winner-less competition and k-winner-take-all states. Finally, I will discuss how these different dynamical states of the striatum can shape the behaviour in healthy and dopamine depleted states.