tDCS of the Left dlPFC: Effects on Information Processing

NCT07168031 | Recruiting

• 1 other identifier: 50012
• Study Type: interventional
• Target: 196
• Locations: 1 country
• Sites: 1

Brief Summary

This study investigates how a non-invasive form of brain stimulation, called transcranial direct current stimulation (tDCS), affects brain activity and information processing in younger and older adults. The stimulation uses a very weak electrical current applied through electrodes placed on the scalp. This method is safe and widely used in research to study brain function. Participants will complete computer-based tasks while receiving either active brain stimulation or a placebo (sham) stimulation. The task is designed to engage specific mental processes so that the investigators can study how the brain responds under different conditions. Brain activity will be measured using magnetic resonance imaging (MRI), both while participants perform the tasks and while they are resting. The study will compare healthy younger (ages 20-40) and older (ages 60-80) adults to explore whether age influences how the brain responds to stimulation. By examining patterns of brain activation and connectivity, the investigators aim to better understand how tDCS can modulate cognitive processing across the adult lifespan. The hypothesis is that applying tDCS to the left dorsolateral prefrontal cortex will change patterns of brain activity related to cognitive processing, and that these changes may differ between younger and older adults. This knowledge could help inform future research into brain stimulation techniques in different age groups.

Conditions

Healthy

Keywords

Non-invasive brain stimulation; tDCS; fMRI; dlPFC; Hippocampus; Ageing; Neuroimaging

Outcome Measures

Primary Outcomes (3)

• Task Accuracy

  Accuracy in responses during an information processing task, measured as the proportion of correct responses.

  During the intervention

• Task-Related Brain Activation

  Changes in blood-oxygen-level-dependent (BOLD) signal during the information processing task, measured using fMRI.

  During the intervention

• Resting-State Functional Connectivity

  Changes in functional connectivity between brain regions before and after stimulation, measured using resting-state fMRI.

  Immediately before and after the intervention

Secondary Outcomes (1)

• Task Reaction Time

  During the intervention

Study Arms (2)

Active tDCS of the Left dlPFC

EXPERIMENTAL

Participants receive active anodal tDCS over the left dorsolateral prefrontal cortex during an information processing task for 22 minutes at 1 mA, with a gradual ramp-up and ramp-down of 30 seconds at the beginning and end of the stimulation.

Device: Active Transcranial Direct Current Stimulation (tDCS)

Sham tDCS of the Left dlPFC

SHAM COMPARATOR

Participants receive sham tDCS with the same setup and initial ramp-up of current to mimic the sensation of active stimulation. The current is turned off after the ramp-up period, and no further stimulation is delivered during the task.

Device: Sham Transcranial Direct Current Stimulation (tDCS)

Interventions

Active Transcranial Direct Current Stimulation (tDCS) DEVICE

High definition tDCS will be applied, using a Soterix Medical device and 4x1 ring electrodes. A centre ring electrode overlying the target cortical region (left dlPFC at position F3 according to the 10-20 system) will be surrounded by four return electrodes (position F1, FC3, F5, and AF3).

Active tDCS of the Left dlPFC

Sham Transcranial Direct Current Stimulation (tDCS) DEVICE

The same setup and device as in the active tDCS group will be used, but in this case stimulation will be turned off after a ramp-up phase of 30 seconds. This mimics the same sensory feeling as active tDCS.

Sham tDCS of the Left dlPFC

Eligibility Criteria

• Age: 20 Years - 80 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Healthy younger adults (ages 20-40) or healthy older adults (ages 60-80)
• Normal or corrected-to-normal vision and hearing
• Right-handed (for consistency in brain stimulation)
• Able to give written informed consent and comply with study procedures

You may not qualify if:

• History of neurological or psychiatric disorders
• Current use of medications that affect the central nervous system
• Metal implants, pacemakers, or other contraindications for MRI or tDCS
• History of seizures or epilepsy
• Pregnancy
• Participation in another brain stimulation study within the last 3 months
• Any condition judged by investigators to interfere with safe participation

Sponsors & Collaborators

• University of Bern: lead

Study Sites (1)

University of Bern, Department of Old Age Psychiatry and Psychotherapy

Bern, 3000, Switzerland

RECRUITING

Study Officials

• Jessica Peter, Prof.

  UniversityClinics, University of Bern

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Sarah Godehardt

CONTACT

+41 58 630 89 03; sarah.godehardt@unibe.ch

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: Participants and investigators will be blinded to the stimulation condition. Both active and sham tDCS procedures involve identical electrode placement and an initial ramp-up of current to produce similar sensations. In the sham condition, the current is turned off after the ramp-up period, preventing ongoing stimulation while maintaining the same setup and experience for participants.
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 28, 2025
• First Posted: September 11, 2025
• Study Start: August 6, 2025
• Primary Completion (Estimated): August 1, 2027
• Study Completion (Estimated): August 1, 2027
• Last Updated: September 11, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share

Locations

CH (1)