Prism Adaptation Modulates Connectivity of the Intraparietal Sulcus with Multiple Brain Networks.

Prism adaptation (PA) alters spatial cognition according to the direction of visual displacement by temporarily modifying sensorimotor mapping. Right-shifting prisms (right PA) improve neglect of left visual field in patients, possibly by decreasing activity in the left hemisphere and increasing it in the right. Left PA shifts attention rightward in healthy individuals by an opposite mechanism. However, functional imaging studies of PA are inconsistent, perhaps because of differing activation tasks. We measured resting-state functional connectivity (RSFC) in healthy individuals before and after PA. When contrasted, right versus left PA decreased RSFC in the spatial navigation network defined by the right posterior parietal cortex (PPC), hippocampus, and cerebellum. Within-PA-direction comparisons showed that right PA increased RSFC in subregions of the PPCs and between the PPCs and the right middle frontal gyrus and left PA decreased RSFC between these regions. Both right and left PA decreased RSFC between the PPCs and bilateral temporal areas. In summary, right PA increases connectivity in the right frontoparietal network and left PA produces essentially opposite effects. Furthermore, right, compared with left, PA modulates RSFC in the right hemisphere navigation network.