Effect of Cross Frequency tACS on Cognitive Control

Previous evidence suggests that there are specific frequency bands associated with different
aspects of cognitive control. In specific delta (2-4Hz) and beta (15-30Hz) are associated
with increased levels of abstraction for learned rules; and theta (5-8Hz) and gamma (30-50Hz)
has been associated with increased set-size or number of learned rules. Here we aim to find
causal evidence in support of these previous correlational findings by applying
cross-frequency transcranial alternating current stimulation (tACS) in the specific frequency
bands previously shown to be task-relevant. In a crossover design, we stimulate subjects with
either delta-beta or theta-gamma tACS during performance of a hierarchical cognitive control
task that manipulates the level of abstraction and set-size of rules that must be learned in
order to make the correct button press.

Inclusion Criteria:

- Between the ages of 18 and 35 years

- Able to provide informed consent

- Willing to comply with all study procedures and be available for the duration of the
study Speak and understand English

Exclusion Criteria:

- Attention Deficit Hyperactivity Disorder (currently under treatment)

- Neurological disorders and conditions, including, but not limited to:

- History of epilepsy

- Seizures (except childhood febrile seizures and electroconvulsive therapy induced
seizures) Dementia

- History of stroke

- Parkinson's disease

- Multiple sclerosis

- Cerebral aneurysm

- Brain tumors

- Medical or neurological illness or treatment for a medical disorder that could
interfere with study participation (e.g., unstable cardiac disease, malignancy)

- Prior brain surgery

- Any brain devices/implants, including cochlear implants and aneurysm clips

- History or current traumatic brain injury

- (For females) Pregnancy or breast feeding

- Personal or family history of mental/psychiatric disorder (e.g., anxiety, major
depressive disorder, schizophrenia, etc.)

- Positive urine test for the following: Marijuana (THC), Cocaine (COC), Phencyclidine
(PCP), Amphetamine (AMP), Ecstasy (MDMA), Methamphetamine (Mamp), Opiates (OPI),
Oxycodone (OXY), Methadone (MTD), Barbiturates (BAR), Benzodiazepines (BZO),
Buprenorphine (BUP), Tricyclic Antidepressants (TCA), Propoxyphene (PPX)

- Anything that, in the opinion of the investigator, would place the participant at
increased risk or preclude the participant's full compliance with or completion of the
study