The neural basis of visual attention
Final Report Abstract
Visual search performance is sensitive to changes in the environment. Attention is sensitive to trial history, in terms of both perception and response. Although the bases of these sensorimotor interactions remain unclear, both behaviorally and neurally, converging evidence from a variety of methods indicates that the right angular gyrus (rANG) may be important. We developed a task capable of revealing both perceptual and response contingencies and how rANG is critically involved in developing them in the sensorimotor control of attention. Parti cipants performed a compound task for feature singleton targets. We applied rTMS over the rANG (or a control site, or no TMS) during the inter-trial interval and measured effects both on behavior and on neural activity using psychophysics and event -related potential (ERP) recording. rANG TMS during the inter-trial interval improved performance to the upcoming stimuli only when the target-defining dimension and the responsedefining feature both repeated across successive trials. rANG TMS also increased the amplitude of the visual N1 component evoked by the upcoming stimuli. These effects did not occur after control TMS.rANG plays a causal role in the formation of combined expectancies binding together stimulus- and response-characteristics of the previous trial to optimize visual search performance. This supports a visu omotor theory of parietal cortex and the dimension weighting a ccount of attention. We suggest current models of inter-trial effects in visual search need to be expanded to include an interactive component representing both perceptual and m otoric inter-trial expectancies, affecting the early analysis of stimulus features in the upcoming trial. Attention is likely to occur through an interaction with other areas, with medial prefrontal areas acting to resolve response conflict and occipital visual areas contributing to spatial capture. Combined TMS-ERP bears promise as method in the future to explore attentional selection.
Publications
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(2012). Brain activity underlying visual perception and attention as inferred from TMS-EEG: a review. Brain Stimulation, 5(2), 124-9
Taylor, P.C., Thut, G.
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(2013). Dissociable Mechanisms Control Conflict during Perception and Response Selection: a Transcranial Magnetic Stimulation study. Journal of Neuroscience, 33(13):5647-5654
Soutschek, A., Taylor, P.C., Müller, H.J., Schubert, T.
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(2015). Occipital TMS at phosphene detection threshold captures attention automatically. Neuroimage, 109, 199-205
Rangelov, D., Müller, H.J., Taylor, P.C.
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(2015). The right angular gyrus combines perceptual and response-related expectancies in visual search: TMS-EEG evidence. Brain Stimulation, 8(4),816-22
Bocca, F., Töllner, T., Müller, H.J., Taylor, P.C.
