Accurate motor control is mediated by internal models of how neural activity generates movement. We examined neural correlates of an adapting internal model of visuomotor gain in motor cortex while two macaques performed a reaching task in which the gain scaling between the hand and a presented cursor was varied. Previous studies of cortical changes during visuomotor adaptation focused on prepa...

OBJECTIVES Determine if ipsilesional primary motor cortex (M1) in stroke patients processes online visuomotor discordance in gain between finger movement and observed feedback in virtual reality (VR). MATERIALS AND METHODS Chronic stroke patients flexed (N= 7) or extended (N= 1) their finger with real-time feedback of a virtual hand presented in VR. Virtual finger excursion was scaled by appl...

The cerebellum, parietal cortex, and premotor cortex are integral to visuomotor processing. The parameters of visual information that modulate their role in visuomotor control are less clear. From motor psychophysics, the relation between the frequency of visual feedback and force variability has been identified as nonlinear. Thus we hypothesized that visual feedback frequency will differential...

The phenomenon of object-centred unilateral neglect suggests that some neural networks process spatial information relative to reference objects. To examine object-centred information processing, we measured regional cerebral blood flow in 11 normal subjects with PET. During each PET scan, a subject viewed a sample stimulus followed by a cue on a video screen. The sample consisted of two polygo...

It is now well established that the visual brain is divided into two visual streams, the ventral and the dorsal stream. Milner and Goodale have suggested that the ventral stream is dedicated for processing vision for perception and the dorsal stream vision for action [A.D. Milner & M.A. Goodale (1995) The Visual Brain in Action, Oxford University Press, Oxford]. However, it is possible that ong...

Learning novel visuomotor tasks requires precise processing and transformation of incoming sensory information to produce accurate motor responses. The present study characterized neural activity associated with sensorimotor processes during novel visuomotor learning. We hypothesized that the acquisition of a visuomotor skill would be accompanied by experience-dependent modulation of sensorimot...

OBJECTIVE The present study examined whether slow and/or fast sleep spindles are related to visuomotor learning, by examining the densities of current sleep spindle activities. METHODS Participants completed a visuomotor task before and after sleep on the learning night. This task was not performed on the non-learning night. Standard polysomnographic recordings were made. After the amplitudes...

During goal-directed reaching, rapid visuomotor feedback processes enable the human motor system to quickly correct for errors in the trajectory of the hand that arise from motor noise and, in some cases, external perturbations. To date, these visuomotor responses, the gain of which is sensitive to features of the task and environment, have primarily been examined in the context of unimanual re...

The cerebellum is critically important for error-driven adaptive motor learning, as evidenced by the fact that cerebellar patients do not adapt well to sudden predictable perturbations. However, recent work has shown that cerebellar patients adapt much better if the perturbation is gradually introduced. Here we explore physiological mechanisms that underlie this distinction between abrupt and g...

The accuracy with which goal-directed movements are executed depends substantially on the availability of accurate visuomotor information. When no visual information is available during movement execution, movement kinematics change and become more variable, indicating that the visual information about the movement environment is stored for a restricted period of time. However, little is known ...