TitleAn adaptive sensorimotor representation for reaching in the inferior parietal lobule of behaving monkeys
NameKarnik, Anushree (author), Krekelberg, Bart (chair), Siegel, Ralph M (internal member), Pare, Denis (internal member), Abercrombie, Elizabeth (internal member), Gardner, Esther (outside member), Rutgers University, Graduate School - Newark,
DescriptionPrimates use visual guidance in order to interact with their environment. For several decades, the inferior parietal lobule (IPL) has been known to contain neurons that respond to visual stimulation and motor behavior. While the neural activity during the reaching behavior has been shown in area 7a of IPL, reach related neural responses have never been tested in the dorsal prelunate area (DP) of IPL, which is adjacent to area 7a. Furthermore, neural response prior to the reaching movement has not been assessed in DP and area 7a. The first aim was to investigate the tuning properties of single neurons in DP and area 7a. The second aim was to assess the influence of eye position signal on reaching behavior. Third, the temporal evolution of sensorimotor transformation in area 7a and DP neurons was investigated by comparing neural signals throughout the reaching task. Lastly, cortical plasticity was tested using Fresnel prisms, which displaced the visual field by 12º in one of four directions: contralateral, ipsilateral, upwards, or downwards. Foveal and peripheral reaching tasks and reaching under perceptually distorted conditions were used. Neurons in area 7a and DP were observed to have differential tuning properties during the planning phase and the initiation of the reach, in addition to being selective for eye position and retinal visual stimulation. The response properties of the neurons in areas 7a and DP changed as the trial progressed in time. Differential preparatory and reach responses were observed during foveal and peripheral reaching. This implies that both eye position and retinal signals modulated the reach related responses. Alterations in spatial tuning of the neurons during all phases of the task were observed upon insertion of the Fresnel prisms imply that neural plasticity occurs as the cortex swiftly adapts to the mismatch between sensory input and motor output. The spatial tuning of the neurons did not merely compensate for the eye position shift implying that signals other than eye position affect the neural response during reaching. These combined results strongly support the claim that crucial aspects of sensorimotor transformation occur in areas 7a and DP.
NoteIncludes bibliographical references
Noteby Anushree Karnik
CollectionGraduate School - Newark Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.