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Abstract:
The role of parietal and frontal cortices in the control of visual attention in humans and macaques is well-known. Recent studies in macaques identified a temporal cortical region involved in the control of visual attention independent of the type of visual stimulation. This temporal cortical region is part of a network including the superior colliculus (SC) in the control of visual attention. In humans, a homolog of this attention-related temporal cortical region has not been identified until now. We set out to locate such an attention-related region in the human temporal cortex using visual stimuli that identified the respective region in macaques, i.e., motion (MS) and dynamic white-noise stimuli (WNS).
In 6 participants (median age: 29 std: 8.6, 2 female), we acquired functional MRI at 9.4T (voxel size 1.5mm isotropic, TR = 1s, TE=21ms) while the participants performed a covert attention task with MS and WNS. The MS was a circular patch of dots with motion direction 30° above horizontal, while the WNS was a dynamic white-noise patch. Two stimuli were presented symmetrically with 4.5° eccentricity relative to a central fixation and 3.5° above horizontal. The covert attention task had three experimental conditions: Attend Left (AL), Attend Right (AR) and Ignore (IG). In AL, the subjects attend to the stimulus in the left visual field and press a button when the attended stimulus changed direction (MS) or a second-order orientation appeared (WNS). In AR, subjects reported on the stimulus in the right visual field. In IG, the subjects ignored the peripheral stimuli and report dimming of the central fixation spot with a button press.
We find a consistent, lateralized activation in MT, MST, FST and PH across motion and non-motion stimuli when contrasting AR vs AL conditions. Posterior-dorsal sub-regions of the TPOJ and medio-dorsal parahippocampal regions also show attentional activation across tasks without lateralization. These findings add to the growing evidence supporting the involvement of sub-regions of the temporal cortex in visual attentional processing. Further analyses will address the interplay between attention-related regions of temporal cortex and subcortical structures.
