Modulation of initial leftward bias in visual search by parietal tDCS

Area of Science:

• Neuroscience
• Cognitive Psychology
• Rehabilitation Science

Background:

• Spatial attention disorders often impair daily functioning.
• Transcranial direct current stimulation (tDCS) is explored for modulating brain activity and cognitive functions.
• Previous research on tDCS and spatial attention primarily focused on visual detection tasks.

Purpose of the Study:

• To investigate the effects of tDCS on spatial attention during visual search and visual imagery in healthy individuals.
• To inform neurorehabilitation strategies for spatial attention deficits.
• To extend the investigation of tDCS beyond visual detection to more complex visual tasks.

Main Methods:

• Forty-eight healthy participants completed computerized visual search and visual imagery tasks.
• Anodal tDCS was applied over the left or right parietal cortex, or a sham condition was used.
• Performance was assessed using measures of target selection bias and spatial distribution.

Main Results:

• tDCS modulated the initial leftward bias in visual search, with right anodal stimulation enhancing it and left anodal stimulation reducing it.
• A marginal improvement in overall visual search performance was observed with right anodal stimulation.
• No significant effects of tDCS or left-right asymmetries were found in the visual imagery task.

Conclusions:

• Parietal tDCS specifically influences the initiation of visual search, offering potential for targeted neurorehabilitation.
• Visual search tasks may be more sensitive to tDCS effects than visual imagery tasks.
• Findings provide insights into the neural mechanisms of spatial attention and its modulation by non-invasive brain stimulation.