Timing of spatial priming within the fronto-parietal attention network: A TMS study

Area of Science:

• Cognitive Neuroscience
• Neuroimaging
• Human Brain Function

Background:

• The posterior parietal cortex (PPC) and dorsolateral prefrontal cortex (DLPFC) form a network for visual spatial attention.
• Top-down control influences processing of targets and distractors, causing priming effects.

Purpose of the Study:

• To investigate the temporal dynamics of top-down attentional control mechanisms.
• To elucidate the role of the right PPC and right DLPFC in spatial attention using transcranial magnetic stimulation (TMS).

Main Methods:

• A spatial negative priming paradigm was employed.
• Single-pulse TMS was applied over the right PPC, right DLPFC, or vertex (sham) at 50, 100, 150, 200, or 250 ms after probe display onset.
• Behavioral responses were measured to assess priming effects.

Main Results:

• TMS over the right DLPFC or right PPC at 100 ms suppressed negative priming at distractor sites.
• TMS at 100 ms over these areas enhanced positive priming at target sites.
• These effects indicate a critical time window for top-down modulation.

Conclusions:

• Top-down attentional mechanisms within the right fronto-parietal network are sensitive to TMS interference around 100 ms post-stimulus.
• This suggests the right DLPFC and PPC play a crucial, time-sensitive role in modulating spatial attention.