Effects of PFC tDCS on Cognitive Control, Attention Lapses and Coordinated Neural Activity in the Theta and Alpha Bands

December 3, 2025 updated by: University of California, Davis

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.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

75

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • California
      • Sacramento, California, United States, 95817
        • Recruiting
        • Imaging Research Center
        • Contact:
        • Principal Investigator:
          • Cameron Carter, M.D.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 50 years (Adult)

Accepts Healthy Volunteers

Yes

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: DLPFC Stimulation
Intervention. 20 minutes of 2 mA direct current stimulation over the dorsolateral prefrontal cortex.
Device: Transcranial 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.
Experimental: Occipital Stimulation
Intervention. 20 minutes of 2 mA direct current stimulation over the occipital cortex.
Device: Transcranial 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.
Sham Comparator: Sham Stimulation
Placebo Comparator. 0.5-1 minutes of 2 mA direct current stimulation over the dorsolateral prefrontal cortex followed by 19-19.5 minutes of sham stimulation
Device: Transcranial 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Behavioral Cognitive Control Measures on the Stroop Task
Time Frame: Through study completion, an average of 1 month
Incongruent versus Congruent difference in error rate and reaction time
Through study completion, an average of 1 month
EEG Cognitive Control Measures on the Stroop Task
Time Frame: Through study completion, an average of 1 month
response-locked power in the theta frequency band (4-7 Hz)
Through study completion, an average of 1 month
Behavioral Attention Lapse Measures on the Stroop Task
Time Frame: Through study completion, an average of 1 month
Error Rate on Incorrect Congruent trials (Full Lapses) and Slow-but-Correct Congruent trials (Partial Lapses)
Through study completion, an average of 1 month
EEG Attention Lapse Measures on the Stroop Task EEG Attention Lapse Measures on the Stroop Task
Time Frame: Through study completion, an average of 1 month
Pre-trial power in the alpha frequency band (8-12 Hz)
Through study completion, an average of 1 month
Behavioral Cognitive Control Measures on the Change Detection Task Behavioral Cognitive Control Measures on the Change Detection Task
Time Frame: Through study completion, an average of 1 month
WM storage capacity (k-max)
Through study completion, an average of 1 month
EEG Cognitive Control Measures on the Change Detection Task
Time Frame: Through study completion, an average of 1 month
delay period power in the theta frequency band (4-7 Hz)
Through study completion, an average of 1 month
Behavioral Attention Lapse Measures on the Change Detection Task
Time Frame: Through study completion, an average of 1 month
Attention factor (a); Guess factor (g)
Through study completion, an average of 1 month
EEG Attention Lapse Measures on the Change Detection Task
Time Frame: Through study completion, an average of 1 month
Pre-trial power in the alpha frequency band (8-12 Hz)
Through study completion, an average of 1 month
Delivered tDCS Dose to PFC
Time Frame: Through study completion, an average of 1 month
Estimated electric field in PFC region of interest
Through study completion, an average of 1 month

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of California, Davis

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 14, 2021

Primary Completion (Estimated)

June 30, 2027

Study Completion (Estimated)

June 30, 2027

Study Registration Dates

First Submitted

May 4, 2021

First Submitted That Met QC Criteria

May 7, 2021

First Posted (Actual)

May 13, 2021

Study Record Updates

Last Update Posted (Estimated)

December 5, 2025

Last Update Submitted That Met QC Criteria

December 3, 2025

Last Verified

December 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 1344169-8

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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