Deconstructing the Neural Dynamics of Anticipation

Performing actions to anticipate rewarding events is an essential aspect of animal survival.  In our lab we study brain circuits involved in learning and generating anticipatory movements in mice.  One of the critical brain structures involved in these processes is the striatum.  As the major input nucleus of the basal ganglia, the striatum receives a diverse array of signals.  Local microcircuits then further process this information, ultimately leading to an output signal via striatal projection neurons.  But beyond this qualitative description and computational models, we have only limited empirical evidence of how striatal dynamics are regulated by its various inputs in behaving animals, and whether microcircuits serve to refine this information.  Therefore, in this talk I will address two questions: what role do different long-range and local inputs have in shaping striatal activity?  And, how are these patterns of activity relevant for behavior?  I will discuss the role of input from motor cortex, midbrain dopaminergic neurons, and parvalbumin-positive interneurons.  We causally probed the contribution of these circuits to striatal dynamics by combining large-scale recordings with optogenetic manipulations.  Our results reveal a highly synergistic relationship between inhibitory striatal microcircuits and excitatory input, whereby inhibition acts to increase the gain and refine the coding properties of incoming cortical signals.  Furthermore, we have found distinct effects of cortical and dopaminergic input on striatal dynamics that appear to underlie the differential behavioral role of these pathways.