Abstract
Despite the huge variability of visual properties in our environment, we can efficiently process the scenes we are embedded in. This processing is supported by three cortical regions: parahippocampal place area (PPA), medial place area (MPA) [or retrosplenial complex, RSC], and occipital place area (OPA). Within the contexts of recognition and navigation, the functions of these regions are generally studied in terms of the visual information they respond to. Here we move beyond these tasks to investigate the role of OPA in guiding eye movements during scene viewing. OPA is i) located in occipito-parietal cortex, likely feeding information into parts of the dorsal pathway critical for eye movements, and ii) contains retinotopic representations of the contralateral visual field. OPA was disrupted with transcranial magnetic stimulation (TMS) while participants searched scenes for 1s. Participants then chose which of two objects had been in the previous scene. On half of the trials, participants received repetitive TMS: a five pulse train over 500ms, starting at scene onset. Half of the participants received TMS to rOPA and half to rOFA (occipital face area), which also exhibits a contralateral visual field bias though is more responsive to face stimuli. If OPA plays a causal role for gaze guidance in scenes, then TMS to rOPA, but not rOFA, should disrupt the eye movement pattern. Given OPA's contralateral representation, eye movements should be biased toward the ipsilateral visual field following rOPA, but not rOFA stimulation. There was an overall left-to-right gaze pattern across all conditions, despite every trial starting at center. Critically, the average fixation position for participants in the rOPA condition was biased toward the ipsilateral visual field and saccade latencies to the ipsifield were shorter. These results suggest that OPA might play a causal role in analysing local scene information for eye movement guidance.
Meeting abstract presented at VSS 2017