Title: Underlying Mechanisms of Cerebellar tDCS Abstract Common symptoms reported with schizophrenia and autism spectrum disorders include poor motor coordination, a deficiency also manifested in cerebellar injuries. Conversely, cerebellar injury patients often suffer from cognitive deficits, including impaired timing, attention, memory and language. Interestingly, changes in cerebellar anatomy are among the most reliable indicators of autism. Therefore, interventions targeting the cerebellum are emerging as an alternative strategy to treat cognitive disorders. Transcranial direct current stimulation (tDCS) of the cerebellum, an easy-to-apply, noninvasive, and safe intervention, has seen a surge of clinical reports in recent years suggesting that it improves motor learning, cognitive and emotional processes. However, few animal studies have investigated the electrophysiological mechanisms underlying the beneficial effects of tDCS on the cerebellar function. The primary objective of the current proposal is to generate the animal experimental data essential to identify the synaptic, cellular, and network level mechanisms by which tDCS impacts the cerebellar function. Classical trace conditioning of the eyeblink response will be used as a model cognitive task that requires coordination of the cerebellum and the prefrontal cortex. The neural mechanisms of how cerebellar tDCS modulates the trace eyeblink conditioning will be investigated in behaving animals. The fundamental knowledge gained through this investigation can be extrapolated to other cognitive and psychiatric disorders that involve the cerebellum and their treatment with tDCS.

Project Narrative In many psychiatric disorders, poor motor coordination accompanies cognitive deficits as commonly reported symptoms. The cerebellum is a primary center of motor coordination and many reports in recent years indicate its involvement in cognition. Clinical data suggest that any treatment method targeting cognitive disorders should consider the cerebellar involvement along with relevant cerebral structures. Transcranial direct current stimulation (tDCS) of the cerebellum has seen a surge of clinical studies in recent years reporting improvements in motor learning, cognitive and emotional processes. However, there have been very few animal studies to explain the mechanism by which the tDCS modulates the cerebellar activity. The primary objective of the current proposal is to investigate the neural mechanisms involved in cerebellar tDCS during a cognitive task in behaving animals. The fundamental knowledge gained through this investigation can lead to the treatment of other cognitive and psychiatric disorders that involve the cerebellum.