32 research outputs found
Control of Reflexive Saccades following Hemispherectomy
Individuals who have undergone hemispherectomy for treatment of intractable epilepsy offer a rare and valuable opportunity to examine the ability of a single cortical hemisphere to control oculomotor performance. We used peripheral auditory events to trigger saccades, thereby circumventing dense postsurgical hemianopia. In an antisaccade task, patients generated numerous unintended short-latency saccades toward contralesional auditory events, indicating pronounced limitations in the ability of a single hemicortex to exert normal inhibitory control over ipsilateral (i.e., contralesional) reflexive saccade generation. Despite reflexive errors, patients retained an ability to generate correct antisaccades in both directions. The prosaccade task revealed numerous contralesional express saccades, a robust contralesional gap effect, but the absence of both effects for ipsilesional saccades. These results indicate limits to the saccadic control capabilities following hemispherectomy: A single hemicortex can mediate antisaccades in both directions, but plasticity does not extend fully to the bilateral inhibition of reflexive saccades. We posit that these effects are due to altered control dynamics that reduce the responsivity of the superior colliculus on the intact side and facilitate the release of an auditory-evoked ocular grasp reflex into the blind hemifield that the intact hemicortex has difficulty suppressing
A geometric method for computing ocular kinematics and classifying gaze events using monocular remote eye tracking in a robotic environment
Contrasting Interpretations of the Nonuniform Distribution of Preferred Directions Within Primary Motor Cortex
Saccades to the seeing visual hemifield in hemidecorticate patients exhibit task-dependent reaction times and hypometria
Random change in cortical load representation suggests distinct control of posture and movement
Nonuniform Distribution of Reach-Related and Torque-Related Activity in Upper Arm Muscles and Neurons of Primary Motor Cortex
Comparison of Neural Responses in Primary Motor Cortex to Transient and Continuous Loads During Posture
Systematic changes in position sense accompany normal aging across adulthood
Article deposited according to publisher policies: http://www.biomedcentral.com/about/copyright June 13, 2014YesFunding provided by the Open Access Authors Fund