Healthy
Conditions
Keywords
Non-invasive brain stimulation, tDCS, fMRI, dlPFC, Hippocampus, Ageing, Neuroimaging
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.
Interventions
DEVICEActive Transcranial Direct Current Stimulation (tDCS)
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).
DEVICESham Transcranial Direct Current Stimulation (tDCS)
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.
Sponsors
University of Bern
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Masking description
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.
Eligibility
Sex/Gender
ALL
Age
20 Years to 80 Years
Healthy volunteers
Yes
Inclusion criteria
* 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
Exclusion criteria
* 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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Task Accuracy | During the intervention | Accuracy in responses during an information processing task, measured as the proportion of correct responses. |
| Task-Related Brain Activation | During the intervention | Changes in blood-oxygen-level-dependent (BOLD) signal during the information processing task, measured using fMRI. |
| Resting-State Functional Connectivity | Immediately before and after the intervention | Changes in functional connectivity between brain regions before and after stimulation, measured using resting-state fMRI. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Task Reaction Time | During the intervention | Time in milliseconds between stimulus presentation and participant response during the information processing task. |
Countries
Switzerland
Contacts
Primary ContactSarah Godehardt
Outcome results
None listed