Selective Attention to Stimulus Location Modulates the Steady-State Visual Evoked Potential

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 93; no. 10; pp. 4770 - 4774
• Main Authors: Morgan, S. T., Hansen, J. C., Hillyard, S. A.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 14.05.1996; National Acad Sciences; National Academy of Sciences
• Subjects: Adult; Attention - physiology; Behavior; Behavioral neuroscience; Brain; Cerebral hemispheres; Electrodes; Evoked potentials; Evoked Potentials, Visual - physiology; Female; Hems; Humans; Male; Neurology; Photic Stimulation; Psychology; Scalp; Selective attention; Spotlights; Visual fields; Visual Fields - physiology; Visual Perception - physiology; Waveforms
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.93.10.4770

Steady-state visual evoked potentials (SSVEPs) were recorded from the scalp of human subjects who were cued to attend to a rapid sequence of alphanumeric characters presented to one visual half-field while ignoring a concurrent sequence of characters in the opposite half-field. These two-character sequences were each superimposed upon a small square background that was flickered at a rate of 8.6 Hz in one half-field and 12 Hz in the other half-field. The amplitude of the frequency-coded SSVEP elicited by either of the task-irrelevant flickering backgrounds was significantly enlarged when attention was focused upon the character sequence at the same location. This amplitude enhancement with attention was most prominent over occipital-temporal scalp areas of the right cerebral hemisphere regardless of the visual field of stimulation. These findings indicate that the SSVEP reflects an enhancement of neural responses to all stimuli that fall within the ``spotlight'' of spatial attention, whether or not the stimuli are task-relevant. Recordings of the SSVEP provide a new approach for studying the neural mechanisms and functional properties of selective attention to multi-element visual displays.