Overnight residues of sensorimotor aftereffects and lack of visuospatial aftereffects following a single prism exposure in healthy subjects.

Abstract

Prism adaptation (PA) is a visuomotor adaptation paradigm resulting in transient sensorimotor shifts. Previous work shows PA can cause additional changes in higher-level visuospatial representations in healthy subjects. In patients with neglect symptoms, records of beneficial visuospatial aftereffects of PA form the basis for its usage as a potential rehabilitation strategy. However, results in both patients and healthy subjects are mixed, with recent studies failing to replicate effects of PA on visuospatial representations. Here, we applied a single session of either right or left PA in healthy subjects (N = 85). Sensorimotor, proprioceptive, and visuospatial biases were measured at baseline, immediately after, 30 minutes, and 24 hours after PA. We found that PA has immediate and robust sensorimotor and proprioceptive aftereffects, replicating previous findings. Crucially, we find that despite expected decay, significant residues of sensorimotor aftereffects can last up to 24 h after PA. In contrast, no short or long-term aftereffects were found on visuospatial attention as measured by the grayscale judgment task. This null result was stable when taking the initial bias of attention orientation into account. No relationship was found between the degree of sensorimotor or proprioceptive responsiveness and visuospatial responsiveness. Our results suggest the effects of PA on the sensorimotor system are less transient than previously thought and are still evident after a night of sleep. Importantly, taken together with recently published null results for the visuospatial effects of PA using other tasks, we suggest these effects might be less extensive than previously reported in healthy subjects.