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.