Modulating Default Mode Network Function: A Transcranial Direct Current Stimulation (TDCS) Pilot Study
Modulating Default Mode Network Function: A Transcranial Direct Current Stimulation (TDCS) Pilot Study
The primary purpose of this research is to gather scientific information about how different
 people's brains work when they look at different types of pictures. This will help to improve
 the investigators' understanding of the way the brain works for people who are depressed or
 anxious, and this knowledge could help lead to better diagnosis and treatment.
In this study the investigators are examining the effects of weak electrical stimulation on
 brain activity as measured by functional magnetic resonance imaging (fMRI). MRI is a widely
 used method to obtain high resolution brain pictures that are routinely used for diagnostic
 and clinical purposes. The electrical stimulation is applied on the scalp with a non-FDA
 approved method called tDCS (transcranial Direct Current Stimulation), typically equivalent
 to what a 6V battery would produce (and up to no more than 15V). To compare, an AA battery
 delivers current at 1.5 volt. While almost unnoticeable to the participants, these currents
 can still temporarily affect brain activity without causing adverse effects. This stimulation
 would be applied while the participants are in the MRI scanner so that the brain activity can
 be measured. The participants will have the opportunity to have a test session with the
 stimulation outside the scanner to get familiar with it.
Inclusion Criteria:

 1. Between 18-30years old

 2. Score > 10 on the QIDS or > 60 on the PROMIS-A

 3. We will use a flexible extreme groups recruitment strategy to ensure an adequate
 distribution of ESC scores. We will ensure that at least 62% of the sample will be
 composed of those scoring .5 SD above or below the mean, as measured by the NEO-PI-R.
 This value corresponds to the expected values assuming a normal distribution of the
 trait.

 4. Normal or corrected to normal vision with contact lenses

 5. Able to provide informed consent in English

 6. Right-handed (Annett criteria)

 Exclusion Criteria:

 1. Have a history of head trauma with loss of consciousness.

 2. Have a systemic medical illness that may impact fMRI measures of cerebral blood flow.

 3. Meet standard exclusion criteria for fMRI scanning (e.g. claustrophobia, cardiac
 pacemakers, neural pacemakers, surgically implanted metal devices, cochlear implants,
 metal braces, or other MRI non-safe metal objects in the body).

 4. Are pregnant (self report and tested for as part of any scan by the scanning center
 and not this protocol)

 5. Not native English speaking or not fluent

 6. Premorbid NAART IQ estimate<85;

 7. Visual disturbance (worse than 20/40 Snellen visual acuity) that is not corrected

 8. If have visual disturbance, only access to correction with glasses (i.e., no access to
 contact lenses).

 9. Left/mixed handedness (Annett criteria), to ensure a uniform hemispheric dominance for
 interpretation of neuroimaging data

 10. Active suicidal ideation in need of immediate treatment

 11. Scoring below the cutoffs on both the QIDS and the PROMIS-A

 12. History of alcohol/substance use disorder (including nicotine) and/or illicit
 substance use (except cannabis) over the last 3 months, determined by the MINI.
 Lifetime/present cannabis use (non-disordered levels) will be allowed, given its
 common usage in individuals in this age range.

 13. Current or past psychotic-spectrum disorder

 14. History of seizures