Transcranial magnetic stimulation over the right dorsolateral prefrontal cortex modulates visuospatial distractor...

Area of Science:

• Neuroscience
• Cognitive Psychology
• Visual Attention

Background:

• Visual selective attention involves filtering relevant information and suppressing irrelevant inputs.
• While facilitation of attended stimuli is well-studied, the neural mechanisms of distractor suppression are less understood.
• The right dorsolateral prefrontal cortex (DLPFC) is implicated in attentional control.

Purpose of the Study:

• To investigate the causal role of the right DLPFC in visuospatial distractor suppression using transcranial magnetic stimulation (TMS).
• To determine the temporal dynamics of DLPFC involvement in distractor suppression.
• To differentiate the role of DLPFC in suppressing location-based versus feature-based (color) distractors.

Main Methods:

• Used 10-Hz repetitive TMS (rTMS) applied to the right DLPFC and Vertex.
• TMS was delivered either at stimulus onset or 500 ms prior to stimulus onset.
• A Posner cueing task variant was employed, requiring participants to identify targets while ignoring distractors.

Main Results:

• Stimulus-onset TMS to the right DLPFC eliminated the location cueing effect, indicating suppression of spatially relevant distractors.
• Prestimulus TMS to the right DLPFC did not affect the cueing effect.
• Stimulus-onset TMS facilitated responses to uncued trials, suggesting a role in inhibiting distractors in both visual fields.
• No significant difference was observed in the effect of right DLPFC TMS on colored versus white distractors.

Conclusions:

• The right DLPFC plays a critical, causal role in visuospatial distractor suppression, acting upon stimulus presentation.
• The DLPFC's contribution to distractor suppression is primarily temporal, influencing processing at the time of stimulus onset.
• The findings suggest the DLPFC is more involved in suppressing location-based distractors than feature-based (color) distractors.