Effects of EEG-vigilance regulation patterns on early perceptual processes in human visual cortex.

OBJECTIVE

To investigate influences of EEG-vigilance regulation patterns on perceptual processing during sustained visual attention in early visual areas.

METHODS

We compared a subject group with stable vigilance regulation to a group with unstable EEG-vigilance regulation. A rapid serial visual presentation stream (RSVP) elicited a 7.5 Hz steady state visual evoked potential (SSVEP), a continuous sinusoidal brain response as a measure of attentional resource allocation during sustained attention in early visual cortex. Subjects performed a target discrimination task. 150 trials were divided into two parts (75 trials each, trial duration: 11 s).

RESULTS

A significant interaction vigilance group by experimental part provided significantly greater SSVEP amplitudes for the unstable group in the second compared to the first part of the experiment. Both groups showed training effects with increased hit rates and d'-values in the second part of the experiment.

CONCLUSIONS

The unexpected finding of SSVEP amplitude increase for the unstable group might be due to competitive interactions for neural resources between the alpha response and SSVEPs.

SIGNIFICANCE

Individual patterns of EEG-vigilance regulation have a moderate impact on early sensory processing during sustained visual attention that is not paralleled in task performance.