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.

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