Submitted on November 26, 2007
Accepted on May 19, 2008
Perceptual load modulates visual cortex excitability to magnetic stimulation
Neil Muggleton1, Ruth Lamb2, Vincent Walsh1, and Nilli Lavie1*
1 Institute of Cognitive Neuroscience, University College London, London, United Kingdom
2 Department of Anatomy and Developmental Biology, University College London, London, United Kingdom
* To whom correspondence should be addressed. E-mail: n.lavie{at}ucl.ac.uk.
Much recent research has shown that the level of perceptual load in a task determines the perception of task-irrelevant stimuli as well as the associated neural activity but the mediating neural mechanisms remain unclear. Here we show that increasing the level of perceptual load in a static letter search task results in an increase in the intensity of transcranial magnetic stimulation over V5/MT required to elicit the perception of a moving phosphene. These findings suggest that the neural mechanisms mediating the effects of perceptual load involve reduced visual cortex excitability in task-unrelated areas.
