Healthy
Conditions
Brief summary
The purpose of this study is to better understand the neural correlates of higher-order cognition, both in the healthy brain and in schizophrenia, and to determine how these mechanisms are modulated by transcranial direct current stimulation (tDCS) at frontal and occipital scalp sites. Testing the effects of tDCS at these scalp sites on cognitive task performance will help us understand the roles of the brain regions corresponding to these sites during higher-order cognitive processing (language comprehension, cognitive control, and related attention and memory processes). Behavioral and electrophysiological (EEG) measures will be used to assess cognitive performance. Our overarching hypothesis is that stimulating prefrontal circuits with tDCS can improve cognitive control performance, and ultimately performance on a range of cognitive tasks, as compared to stimulating a different cortical region (occipital cortex) or using sham stimulation. This study is solely intended as basic research in order to understand brain function in healthy individuals and individuals with schizophrenia. This study is not intended to diagnose, cure or treat schizophrenia or any other disease.
Interventions
DEVICETranscranial Direct Current Stimulation
In tDCS, saline-soaked electrodes are temporary affixed to the scalp and connected to a battery-powered current generator. A weak (2 mA) constant current is then briefly applied (\ 20 minutes) to stimulate the targeted brain area. The targeted brain area is determined by the Study Arm.
Sponsors
University of California, Davis
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to 50 Years
Healthy volunteers
Yes
Inclusion criteria
* between ages of 18 and 50 * ability to sufficiently speak and understand English so as to be able to understand and complete cognitive tasks * ability to give valid informed consent
Exclusion criteria
* no history of head trauma * no current or previous history of treatment with psychotropic medication * corrected vision 20/30 or better * tDCS/MRI contraindications, including: pregnancy, ferrous metal in any part of the body, serious medical conditions, claustrophobia, metallic implants, skin damage, conditions such as eczema at electrode sites, cranial pathologies
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Behavioral Cognitive Control Measures on the Stroop Task | Through study completion, an average of 1 month | Incongruent versus Congruent difference in error rate and reaction time |
| EEG Cognitive Control Measures on the Stroop Task | Through study completion, an average of 1 month | response-locked power in the theta frequency band (4-7 Hz) |
| Behavioral Attention Lapse Measures on the Stroop Task | Through study completion, an average of 1 month | Error Rate on Incorrect Congruent trials (Full Lapses) and Slow-but-Correct Congruent trials (Partial Lapses) |
| EEG Attention Lapse Measures on the Stroop Task EEG Attention Lapse Measures on the Stroop Task | Through study completion, an average of 1 month | Pre-trial power in the alpha frequency band (8-12 Hz) |
| Behavioral Cognitive Control Measures on the Change Detection Task Behavioral Cognitive Control Measures on the Change Detection Task | Through study completion, an average of 1 month | WM storage capacity (k-max) |
| EEG Cognitive Control Measures on the Change Detection Task | Through study completion, an average of 1 month | delay period power in the theta frequency band (4-7 Hz) |
| Behavioral Attention Lapse Measures on the Change Detection Task | Through study completion, an average of 1 month | Attention factor (a); Guess factor (g) |
| EEG Attention Lapse Measures on the Change Detection Task | Through study completion, an average of 1 month | Pre-trial power in the alpha frequency band (8-12 Hz) |
| Delivered tDCS Dose to PFC | Through study completion, an average of 1 month | Estimated electric field in PFC region of interest |
Countries
United States
Contacts
Primary ContactMinhtrang Chu
Outcome results
None listed