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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
196
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).
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.
University of Bern, Department of Old Age Psychiatry and Psychotherapy
Bern, Switzerland
RECRUITINGTask Accuracy
Accuracy in responses during an information processing task, measured as the proportion of correct responses.
Time frame: During the intervention
Task-Related Brain Activation
Changes in blood-oxygen-level-dependent (BOLD) signal during the information processing task, measured using fMRI.
Time frame: During the intervention
Resting-State Functional Connectivity
Changes in functional connectivity between brain regions before and after stimulation, measured using resting-state fMRI.
Time frame: Immediately before and after the intervention
Task Reaction Time
Time in milliseconds between stimulus presentation and participant response during the information processing task.
Time frame: During the intervention
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