Contralateral visual search deficits following TMS

Area of Science:

• Neuroscience
• Cognitive Psychology
• Visual Perception

Background:

• Transcranial magnetic stimulation (TMS) can reveal causal links between brain regions and cognitive functions.
• Previous research indicated differential effects of TMS on posterior parietal cortex (PPC) and superior temporal gyrus (STG) for conjunction versus feature visual search tasks.

Purpose of the Study:

• To investigate the specific spatial deficits induced by TMS over PPC and STG when participants must make left/right location decisions.
• To determine if these deficits are lateralized and dependent on the spatial configuration of visual search arrays.

Main Methods:

• Non-invasive brain stimulation using TMS over PPC and STG in separate experimental blocks.
• Participants performed visual search tasks using full-field or hemispace-presented structured arrays.
• Performance was assessed based on accuracy and reaction time for target localization (left/right decision).

Main Results:

• TMS over PPC resulted in a specific deficit in searching contralateral space with full-field arrays.
• TMS over STG led to a specific deficit in identifying targets in contralateral portions of smaller, structured arrays presented within a hemispace.

Conclusions:

• The findings demonstrate distinct, lateralized spatial processing roles for PPC and STG in visual search.
• PPC is crucial for contralateral spatial awareness in a global search context.
• STG plays a role in processing spatial information within specific hemifields, particularly in structured visual environments.