Summary
The purpose of this study is to understand how the brain controls movement and how Non-invasive Brain Stimulation (NIBS) with a technique called High-density transcranial direct current stimulation (HD-tDCS) can alter brain processes to improve behavior. Participants in this study will be randomized to either HD-tDCS with standard intervention or personalized dose-controlled multifocal network-targeted HD-tDCS.
The hypothesis is that dexterous hand function will improve after a standard HD-tDCS dose and increase even more after personalized dose-controlled multifocal network-targeted HD-tDCS.
Eligibility Criteria
Age Range: 65 years to 85 years
Inclusion Criteria:
* Participants should be in good health with normal or corrected-to-normal visual acuity
* Right handed
* No history of neurological disorder
* English speaker
* Able to provide written consent prior to admission
Exclusion Criteria:
* Left-handed
* Participants are pregnant, suspect pregnancy or are attempting to become pregnant
* Have a pacemaker, intracardiac lines or any other medically implanted device or medicine pump
* Have cochlear hearing implants
* Taking drugs known to influence neural receptors that facilitate neuroplasticity (see protocol)
* Have non removable body piercings or have foreign objects in body
* Have metal anywhere in the head that could increase risk of serious injury (not including braces, dental fillings, etc.) (see protocol)
* Have a personal or family history of seizure/epilepsy
* Taking prescription drugs that lower the threshold for seizures
* Recent history of excessive alcohol consumption
* History of alcohol addiction/dependence
* Recent history of recreational drug use
* History of drug addiction/dependence
* Recent history of recreational drug use
* History of drug addiction/dependence
* Diagnosed with a stroke, brain hemorrhage, brain tumor, encephalitis.
* Diagnosed with multiple sclerosis
* Diagnosed with Parkinson's disease or Alzheimer's disease
* Diagnosed with depression in the past 6 months
* Diagnosed with attention deficit disorder, schizophrenia, manic depressive (bipolar) disorder
* Diagnosed with normal pressure hydrocephalus or increased intra-cranial pressure
* Diabetes requiring insulin treatment
* Any serious heart disorder or liver disease