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Jennifer Highsmith, Zenaida Santiago, Michael A. Crognale; Chromatic pattern-onset VEPs are robust to inattention. Journal of Vision 2007;7(9):646. doi: 10.1167/7.9.646.
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© ARVO (1962-2015); The Authors (2016-present)
Introduction: Attention has been shown to affect both behavioral and electrophysiological measures of visual processing. In addition, it is often difficult to determine whether or not a subject is attentive to the stimulus. Electrophysiological effects are often evident when attention is divided across space. In other studies where VEP and distracter stimuli remain spatially coextensive, changes in waveforms are not always seen. In this study we measured the effects of divided attention with spatially separated distracters on the chromatic pattern on-set VEP as might occur when a subject is looking at but not attending to the stimulus.
Methods: Stimuli were 1 cycle/degree horizontal sine-wave gratings modulated along the L-M and S-(L+M) axis in color space and presented in a pattern-onset mode. Subjects centrally fixated the VEP stimuli on one monitor while attending to an adjacent monitor and performing a judgment task on the distracter stimuli displayed thereon. Subject gaze and performance was monitored to ensure fixation and attention were directed to the proper monitors.
Results: No change in waveform amplitude and latency, as compared to typical VEP viewing conditions, was found when fixation remained on the VEP stimuli and attention was diverted to an adjacent monitor. Attention to the stimulus is not necessary for a robust chromatic pattern on-set VEP response. These results reinforce the clinical utility of the chromatic onset VEP in populations that may have difficulty maintaining an attentive state or following verbal instructions.
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