Left Parietal Regions Are Critical for Adaptive Visuomotor Control

Abstract

The question addressed in this study is whether parietal brain circuits involved in adaptation to novel visuomotor conditions, are lateralized. This information is critical for characterizing the neural mechanisms mediating adaptive behavior in humans, as well as for assessing the effects of unilateral brain damage on function. Moreover, previous research has been controversial in this regard. We compared visuomotor adaptation in 10 patients with focal, unilateral, left or right parietal lesions and healthy control participants. All subjects reached to each of eight targets over three experimental sessions: a baseline session, where the visually-displayed and actual hand motion were matched; an adaptation session where the visual feedback deviated from the actual movement direction by 30-degrees and an after-effect session where visual feedback was again matched to hand motion. Adaptation was primarily quantified as a change in initial movement direction throughout the adaptation session and the presence of after-effects when the rotation was removed. Patients with right parietal damage demonstrated normal adaptation and large after-effects, which was comparable to the performance of healthy controls. In contrast, patients with left parietal damage showed a clear deficit in adaptation and showed no after-effects. Thus, our results show that left, but not right parietal regions are critical for visuomotor adaptation. These findings are discussed in the context that left parietal regions are critical for the modification of stored representations of the relationship between movement commands and limb and environmental state, as is thought to occur during visuomotor adaptation.

The cost of moving with the left hand

“…Hemispheric specialization for different aspects of movement is also observed in adaptation tasks. Mutha et al (2011) compared visuomotor adaptation in patients with LH or RH lesions and observed adaptation only in those with an intact LH. Lefthand adaptation to prism displacement transfers to performance with the right, but right-hand adaptation does not transfer to the left hand Wallace 2008, 2009).…”

Hemispheric differences in the control of limb dynamics: a link between arm performance asymmetries and arm selection patterns

“…Although this evidence inspired a departure from Liepmann's view of a comprehensively dominant left hemisphere, this change was only recently incorporated into theories of handedness (Carson 1993;Sainburg 2002). The view that each hemisphere may be specialized for different aspects of motor control has led to the understanding that unilateral hemisphere damage produces unique motor deficits that depend on the side of the lesion (Haaland and Flaherty 1984;Mani et al in press;Mutha et al 2011). Perhaps more importantly, hemisphere-specific deficits also occur in the ipsilesional arm of stroke patients, demonstrating that each hemisphere contributes different processes to control of each arm (Schaefer et al 2007(Schaefer et al , 2009.…”

The Neuropsychology of Movement and Movement Disorders: Neuroanatomical and Cognitive Considerations

“…Other work has shown that damage or disruption of left, but not right, parietal cortex also disrupts 772 K.Y. Haaland et al motor adaptation (Della-Maggiore, Malfait, Ostry, & Paus, 2004;Mutha, Sainburg, & Haaland, 2011). This suggests that parietal cortex is critical not just for motor planning, but also for updating and maintaining new internal representations that are important for motor planning.…”