Abstract
Knowledge of the normal organization of visual field map clusters allows us to study potential reorganization within visual cortex under conditions that lead to a disruption of the normal visual inputs. Here we exploit the dynamic nature of visuomotor regions in posterior parietal cortex to examine cortical functional plasticity induced by a complete reversal of visual input in normal adult humans. We also investigate whether there is a difference in the timing or degree of a second adaptation to the left-right visual field reversal in adult humans after long-term recovery from the initial adaptation period. Subjects wore left-right reversing prism spectacles continuously for 14 days and then returned for a 4-day re-adaptation to the reversed visual field 1-9 months later. For each subject, we used population receptive field modeling fMRI methods to track the receptive field alterations within the occipital and parietal visual field map clusters across time points. The results from the first 14-day experimental period highlight a systematic and gradual shift of visual field coverage from contralateral space into ipsilateral space in parietal cortex throughout the prism adaptation period. After the second, 4-day experimental period, the data demonstrate a faster time course for both behavioral and cortical re-adaptation. These measurements in subjects with severely altered visual input allow us to identify the cortical regions subserving the dynamic remapping of cortical representations in response to altered visual perception and demonstrate that the changes in the maps produced by the initial long prism adaptation period persist over an extended time.
Meeting abstract presented at VSS 2012