Tsc1 Regulation of Purkinje Neuron Firing and Cerebellar Function - Autism spectrum disorder (ASD) is a prevalent neurodevelopmental disorder that affects an estimated 1 in 59 individuals. ASD diagnoses involve a range and often heterogenous assortment of symptoms, which include impaired social interactions, motor coordination, communication ability, and vocalizations, as well as exaggerated repetitive movements. Our understanding, however, of the molecular, cellular, and neural circuit dysfunction that drives ASD-linked behaviors remains unclear. Another neurodevelopmental disorder, tuberous sclerosis, is caused by loss of function mutations in tuberous sclerosis 1 or 2 (Tsc1, Tsc2). Interestingly, >50% of individuals with Tsc are also diagnosed with ASD, making Tsc mutations one of the most prevalent monogenetic causes of ASD. In mice, the selective deletion of one or two Tsc1 alleles selectively in cerebellar Purkinje neurons (Pcp2:Tsc1+/-, Pcp2:Tsc1-/-) results in multiple autistic-like behaviors. With this animal model, we can connect the dysfunction of a single neuronal cell type, Purkinje neurons in the cerebellum, with autistic-like behaviors. Initial studies using Pcp2:Tsc1 mice revealed that Purkinje neurons lacking Tsc1 expression fire at lower rates than wild type Purkinje neurons. In the following aims, we will extend these studies by (1) defining the molecular and biophysical changes that cause reduced firing rates in Pcp2:Tsc1+/- and Pcp2:Tsc1-/- Purkinje neurons, and (2) determine how the reduced firing rates of Pcp2:Tsc1+/- and Pcp2:Tsc1-/- Purkinje neurons affect the in vivo activity of deep cerebellar nuclei neurons, which, in the context of cerebellar circuits, are the downstream targets of Purkinje neurons. These experimental aims will involve training and collaborative research efforts by graduate and undergraduate students at Miami University.
