Attention is allocated closely ahead of the target during smooth pursuit eye movements: Evidence from EEG frequency tagging.
It is under debate whether attention during smooth pursuit is centered right on the pursuit target or allocated preferentially ahead of it. Attentional deployment was previously probed using a secondary task, which might have altered attention allocation and led to inconsistent findings. We measured frequency-tagged steady-state visual evoked potentials (SSVEP) to measure attention allocation in the absence of any secondary probing task. The observers pursued a moving dot while stimuli flickering at different frequencies were presented at various locations ahead or behind the pursuit target. We observed a significant increase in EEG power at the flicker frequency of the stimulus in front of the pursuit target, compared to the frequency of the stimulus behind. When testing many different locations, we found that the enhancement was detectable up to about 1.5° ahead during pursuit, but vanished by 3.5°. In a control condition using attentional cueing during fixation, we did observe an enhanced EEG response to stimuli at this eccentricity, indicating that the focus of attention during pursuit is narrower than allowed for by the resolution of the attentional system. In a third experiment, we ruled out the possibility that the SSVEP enhancement was a byproduct of the catch-up saccades occurring during pursuit. Overall, we showed that attention is on average allocated ahead of the pursuit target during smooth pursuit. EEG frequency tagging seems to be a powerful technique that allows for the investigation of attention/perception implicitly when an overt task would be confounding.
['Chen|Jing|J|', 'Valsecchi|Matteo|M|', 'Gegenfurtner|Karl R|KR|']
D000293:Adolescent D000328:Adult D001288:Attention D001931:Brain Mapping D004569:Electroencephalography D005074:Evoked Potentials, Visual D005260:Female D005403:Fixation, Ocular D006801:Humans D008297:Male D008875:Middle Aged D010775:Photic Stimulation D011698:Pursuit, Smooth D014796:Visual Perception D055815:Young Adult
Attention Smooth pursuit eye movements Frequency tagging SSVEP