Cerebellar Stimulation and Cognitive Control

Our recent work found that patients with Parkinson's disease and schizophrenia have impaired
frontal EEG rhythms in the theta and delta range (1-8 Hz).We have been using transcranial
direct current stimulation to recover these rhythms as patients perform elementary cognitive
tasks. We found that although we are able to modulate cerebellar and frontal activity with
tDCS, this effect is minimal as the depth of the current is not great enough to modulate all
cerebellar activity. Here we use transcranial magnetic stimulation (TMS) to modulate neural
activity in the frontal cortex and recover cognitive function in patients with autism,
schizophrenia, bipolar disorder and Parkinson's disease.

The purpose of the study is to explore cerebellar stimulation as a potential new treatment to
restore frontal activity and cognitive function in autism, schizophrenia, bipolar disorder
and Parkinson's disease.Subjects will be brought in for 5 to 6 separate visits, with
cerebellar or sham TMS stimulation twice per day for 5 days, as well as 3 follow-up
visits.During these visits the patient will have cognitive, disease-specific and emotional
testing, including EEG testing and MRI imaging. For those participants that received sham
stimulation we will again use EEG to record how single pulses of magnetic or electrical
stimulation influences other regions of the cerebellum and downstream brain regions. These
data will provide insight into how the cerebellum may influence downstream brain regions and
play a role in cognitive and motor performance. All data will be analyzed offline to
determine if performance on the interval timing task and/or frontal brain rhythms change
following transcranial magnetic stimulation as compared to the pre-stimulation blocks of
trials. Additionally, we will analyze changes in their cognitive function, symptom ratings,
functional and structural MRI, and mood following stimulation. Controls will receive both
active and sham treatment for comparison.

Inclusion Criteria:

- A clinical diagnosis consistent with enrollment

Exclusion Criteria:

- History of recurrent seizures or epilepsy

- Any other neurological or psychiatric diagnosis outside the diagnosis for which the
participant is enrolled.

- Active substance use disorder in the past 6 months other than tobacco use disorder.

- Inability to consent for study.

- Pacemaker

- Coronary Stent

- Defibrillator

- Neurostimulation

- Claustrophobia

- Uncontrolled high blood pressure

- Atrial fibrillation

- Significant heart disease

- Hemodynamic instability

- Kidney disease

- Pregnant, trying to become pregnant, or breast feeding