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Abstract:
Visual attention selects only a tiny fraction of visual input information for further processing. Selection starts in the primary visual cortex (V1), which (via lateral/recurrent mechanisms within V1) creates a bottom-up saliency map to guide the fovea to selected visual locations via gaze shifts (via V1’s projection to the superior colliculus). It suggests a massive loss of non-selected information from V1 downstream along the visual pathway. Hence, feedback from downstream visual cortical areas to V1 for better recognition, though analysis-by-synthesis, should query for additional information and be mainly directed at the foveal region. Hence, peripheral vision is mainly for looking (to select a peripheral location to attend or shift gaze to), while central vision is mainly for seeing (or visual decoding). Accordingly, non-foveal vision is not only poorer in spatial resolution, but also more susceptible to various problems such as illusions and crowding. Therefore, V1 is a center-stage for both the bottom-up and top-down processes, rather than an early visual cortex. Visual processes beyond V1 should be understood in light of V1’s role. Relevant behavioral, physiological, anatomical, and fMRI data will be presented to illustrate the above.
