Venue: Centre Broca
Maxime Assous,
Associate professor
Rutgers University, USA
Invited by Nicolas Mallet
Title
Novel interneuronal circuits modulate striatal output and striatal dependent behaviors
Abstract
The striatum is the main input structure of the basal ganglia (BG), the largest group of interconnected subcortical nuclei. The BG is essential for voluntary motor control, several types of learning and other higher cognitive functions. Among the most important recent discoveries about the functional organization of the striatum, resulting largely from work in our laboratory, is the existence of a highly diverse population of GABAergic interneurons whose anatomy, physiology and connectomes have been the principal focus of my research for the past 8 years.
I will first review some of these principal findings including the discovery of 4 classes of novel GABAergic interneurons, their electrophysiological properties and their heretofore unknown highly selective and specific intrastriatal connectivity.
Next, I will review some of my more recent work on the specificity and selectivity of excitatory afferent inputs to these interneurons, focusing on a novel disynaptic thalamostriatal pathway as well as a novel source of extrinsic glutamatergic originating from the pedunculopontine nucleus, selectively innervating striatal interneurons.
In the next part of the talk, I will describe some of the first studies of extrinsic GABAergic inhibitory inputs to striatal projection neurons and interneurons from subtypes of globus pallidus (GP) neurons. Using various viral transduction strategies and intersectional approaches to identify GP neurons on the bases of their genetic profile and specific cellular projection targets, I will show the selective innervation of different striatal projection neurons and interneurons by prototypic and arkypallidal GP neurons. Further, I will outline some preliminary results investigating the functional role of these striatal extrinsic inhibitory projections.
Lastly, I will describe the impact of subtypes of nicotinic receptors, specifically those that contain the beta-2 subunit, on striatal neuronal activity and behaviors.