The Effect of Transcranial Direct Current Stimulation on Visual Attention - Single Sessions

Masaryk University50 enrolled

Overview

Recently, attention has been drawn to non-invasive brain stimulation techniques, such as transcranial direct current stimulation (tDCS), in order to enhance cognitive functions by modifying brain plasticity and use it in different healthy and diseased populations. In the current research, investigator aim to examine the short-term effects of multiple tDCS protocols in healthy adults population on visual attention and identify the neural underpinnings of tDCS-induced behavioral aftereffects using a combined tDCS/ MRI network-based approach.

Investigator will investigate the shor-term effects of active tDCS as compared to a placebo stimulation on visual attention in the healthy seniors. A cross-over, randomized, placebo-controlled design will be used. Single tDCS sessions will be performed in 4 sessions over distinct brain areas with ongoing visual attention training. During the stimulation, investigator will use the visual matching task. MRI protocol consisting of T1 and resting state fMRI sequences will be acquired before and after every stimulation session in order to search for active vs. placebo tDCS-induced changes in brain activation and resting state functional connectivity and to identify neural correlates of behavioral changes.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

SUPPORTIVE_CARE

Masking

QUADRUPLE

Enrollment

Conditions

Healthy Aging Cognitive Change

Eligibility

Sex: ALLMin age: 18 YearsMax age: 80 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * right handed, healthy volunteers in two groups - healthy adults under 40 years, healthy seniors over 50 years Exclusion Criteria: * psychiatric disorders, including major depression, major vascular lesions, and other brain pathologies detected by MRI that might present with cognitive decline * a cardio pacemaker or any MRI-incompatible metal in the body * epilepsy * any diagnosed psychiatric disorder * alcohol/drug abuse * lack of cooperation * presence of cognitive impairment

Outcomes

Primary Outcomes

Visual-attention task accuracy

Task will be presented on a computer and subject will respond by YES-NO buttons. Only if there are no differences in task accuracy, we will measure task reaction times (e.g. due to the roof effect).

Time frame: Change from baseline immediately after completion of stimulation protocol

Magnetic resonance imaging

Investigator will record high resolution structural T1-weighted (MPRAGE) images, functional T2\* weighted multiband EPI sequences. The total time spent in the scanner will be approximately 40 in every session.