Contribution of Human Prefrontal Cortex to Delay Performance
Journal of Cognitive Neuroscience
Distributed cortical network for visual attention
Journal of Cognitive Neuroscience
Prestimulus cortical activity is correlated with speed of visuomotor processing
Journal of Cognitive Neuroscience
Journal of Cognitive Neuroscience
Alpha oscillations correlate with the successful inhibition of unattended stimuli
Journal of Cognitive Neuroscience
Somatosensory anticipatory alpha activity increases to suppress distracting input
Journal of Cognitive Neuroscience
Working memory processes are mediated by local and long-range synchronization of alpha oscillations
Journal of Cognitive Neuroscience
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The ongoing neural activity in human primary somatosensory cortex (SI) is characterized by field potential oscillations in the 7-13 Hz range known as the mu rhythm. Recent work has shown that the magnitude of the mu oscillation immediately preceding the onset of a weak stimulus has a significant impact on its detection. The neural mechanisms mediating this impact remain not well understood. In particular, whether and how somatosensory mu rhythm is modulated by executive areas prior to stimulus onset for improved behavioral performance has not been investigated. We addressed these issues by recording 128-channel scalp electroencephalogram from normal volunteers performing a somatosensory perception experiment in which they reported the detection of a near-threshold electrical stimulus (â聢录50% detection rate) delivered to the right index finger. Three results were found. First, consistent with numerous previous reports, the N1 component (â聢录140 msec) of the somatosensory-evoked potential was significantly enhanced for perceived stimulus compared to unperceived stimulus. Second, the prestimulus mu power and the evoked N1 amplitude exhibited an inverted-U relationship, suggesting that an intermediate level of prestimulus mu oscillatory activity is conducive to stimulus processing and perception. Third, a Granger causality analysis revealed that the prestimulus causal influence in the mu band from prefrontal cortex to SI was significantly higher for perceived stimulus than for unperceived stimulus, indicating that frontal executive structures, via ongoing mu oscillations, exert cognitive control over posterior sensory cortices to facilitate somatosensory processing.