In a randomized, triple-blind, sham-controlled clinical trial, we will assess the effect of a single session frontal cortex High-Definition transcranial Direct Current Stimulation (HD-tDCS) on brain activity and functional connectivity underlying the behavioral change in attentional control in healthy participants. Participants will be recruited after meeting the inclusion criteria and will be randomly assigned to active or sham stimulation groups. All participants will undergo resting-state functional Magnetic Resonance Imaging (rsfMRI) scan and perform an Attention Network Test (ANT) in a functional Magnetic Resonance Imaging (fMRI) scanner before and after receiving a single session of active or sham HD-tDCS.

Inclusion Criteria:

• Right-handed healthy adults
• Age range 20-39 years
• Normal or corrected-to-normal vision
• Willing and capable of following study protocol requirements given in the informed consent

Exclusion Criteria:

• Psychiatric conditions (e.g., depression and generalized anxiety disorder, etc.)
• Medical illness or neurological disorder (e.g., cardiovascular illness, anemia, respiratory illness, neurological illness, seizure, etc.)
• Current abuse of drugs or alcohol
• Any conditions that prevent undergoing an fMRI scan or tDCS stimulation according to the fMRI and tDCS safety checklists

Triple-blind study