Attention operates differently across eccentricities
Poster
Authors/Editors
Strategic Research Themes
Publication Details
Author list: Sirawaj Itthipuripat, Tanagrit Phangwiwat, Phond Punchongharn, Itthi Chatnuntawech, Chaipat Chunharas, Thomas Sprague , Sisi Wang, Geoffrey F. Woodman
Publication year: 2021
Abstract
In primates, foveal and peripheral vision have distinct neural architectures and functions.
However, it has been debated if selective attention operates via the same or different neural
mechanisms across these different eccentric locations. We hypothesized that the discrepancies
between past results arose in part from the differences in neural signals used to index
attentional modulations and the differences in task difficulty across eccentricities. Here, we
measured three EEG indices of visual processing, while male and female human subjects
performed a visual attention task, where they either attended to the fixation or to the visual
stimuli presented at different eccentricities. These EEG indices include the amplitudes of the
steady-state visually evoked potentials (SSVEPs), the sustained negative deflection (SND), and
the alpha band activity. Critically, we equated task difficulty across the different attention conditions and eccentricities. Overall, the amplitudes of these neural markers reduce as a function of eccentricity, reflecting changes in cortical magnification. However, they expressed totally different patterns of attentional modulations across eccentricities. The SSVEP exhibitedprominent attentional gain modulations at the peripheral locations, but attentional modulations were significantly reduced at the parafoveal locations. In contrast, the SND showed relatively similar levels of attentional modulations across the parafoveal and the peripheral locations. On
the other hand, alpha band activity exhibited significant attentional modulations only at the
peripheral locations, which relied primarily on the relative differences between the contralateral
and ipsilateral signals. Taken together, these results suggest that sustained visual attention
comprises multiple biophysical processes that differentially impact sensory information processing across eccentricities.
Keywords
No matching items found.