Abstract
Visuospatial information processing capabilities need to be experientially malleable in order to enable sighted organisms to adapt to dynamic environments. This work examined visuocortical changes at the neuronal population level as human observers learned to associate specific spatial locations with aversive outcomes. High-density EEG was recorded while 50 healthy undergraduate students viewed individually presented, high-contrast Gabor patches appearing at one of five different locations. Patches were flickered to produce steady-state visual evoked potentials (ssVEPs) at a temporal frequency of 15 Hz, with one of the spatial locations (manipulated between-participants) paired with an aversive 90 dB white noise auditory stimulus for the final 200 (out of 350 total) trials. Alpha band (9.6 – 13.2 Hz) and ssVEP signals were source-localized via minimum norm estimation, and amplitude changes following conditioning were evaluated for trends consistent with either sharpening (i.e. lateral inhibition; amplification of the conditioned location and suppression of nearby locations) or generalization (amplification of the conditioned location, with amplitude gradually decreasing with increasing distance) across the five spatial locations. Indexed by ssVEP amplitudes, conditioned locations sharpened responses in retinotopic visual cortex, with stimuli presented in the left visual field eliciting the most pronounced changes. Alpha-band power reduction, often associated with the engagement of attention and alertness/arousal mechanisms, was also most prominent when viewing Gabors at locations paired with the noxious noise. Results suggest that learning to associate spatial locations with aversive outcomes prompts both sharpening of retinotopic visual field representations as well as the selective engagement of higher order, endogenous biasing mechanisms indicated by alpha-band power reduction.