Cerebellum's Role in Perceptual Timing Behavior

New York University School Of Medicine, New York NY

Investigators

Abstract

The perception of time, and more generally, the use of temporal information, is an integral part of our everyday experience. It is thus an essential capability of the brain. Despite its importance, the network underlying the ability to time events on relatively short time scales (i.e., seconds or less) is not fully known. We believe the cerebellum is a strong candidate for being a member of this network for several reasons. It has a well- established role in timing motor responses, and the near constancy of its intrinsic circuitry suggests that it should perform similar computations for both its motor and non-motor functions. Furthermore, our preliminary data from a perceptual timing task provide evidence that the lateral cerebellum plays a role in perceiving the duration of sensory events. Thus, we propose to investigate the cerebellum's role in time perception using electrophysiological and optogenetic techniques in combination with a standard (temporal bisection) and a novel (trianchor bisection) interval timing task. In these tasks, rats discriminate auditory stimuli based on their duration for a reward. In Aim I, we will selectively manipulate the activity of identified cerebellar neuronal populations using optogenetic tools in order to provide evidence of a causal link between the activity of lateral cerebellar neurons and the perceived duration of the sensory stimuli. We will test how task-related information is encoded by specific classes of cerebellar nuclear neurons, including cerebellar nuclear cells that project to the thalamus and cerebellar nuclear cells that receive input from crus 1 of the cerebellar cortex, a region implicated in cognitive functions and that is interconnected with prefrontal cortical areas. Various optogenetic stimulation patterns will be tested for their effects on timing behavior in the temporal bisection tasks to investigate which spike train parameters may be used to encode task-related information. In Aim 2, we will record from cerebellar neurons and determine the correlates of their activity with the animal's performance on the temporal bisection task. We will also investigate the possibility of other behavioral correlates of lateral cerebellar activity, and determine whether temporal and non-temporal information is encoded by the same or separate neuronal populations. The information gained through these experiments will improve our understanding of how the cerebellum encodes information about time perception and how it interacts with other brain regions involved in this process. Such knowledge should also improve our understanding of how dysfunction of the cerebellum contributes to a variety of neurological and psychiatric disorders.