Neural control of coordinated oculomotor and skeletomotor movements.
The nervous system continuously monitors the environment and, when necessary, produces overt or covert behavior in response to the sensory stimulation. To facilitate orientation towards objects of interest, the sensory representation of target location is transformed into neural commands that evoke a complex, coordinated, and accurate movement. Thus, one aim of my research is to understand the neural implementation of coordinated movements. More specifically, I am interested in investigating cortical and subcortical mechanisms that control coordinated movements of the eyes and head, as well as integration of different types of eye movements (for example, saccades and smooth pursuit).
In producing orienting behavior, the efficacy of sensory to motor transformation depends on cognitive processes. One such mechanism, motor preparation, proposes that neural signals encoding the metrics of a desired movement develop gradually. A second area of research is geared to test the motor preparation hypothesis and to investigate the extent of its association with other sensorimotor attributes, which are emphasized by varying task-specific requirements.
These objectives are addressed using both experimental (extracellular recording, microstimulation, chemical microinjections) and computational tools (lumped and distributed network models). An understanding of the cognitive and motor processes that produce integrated orienting behavior has diagnostic value for deficits resulting from disease.
Gandhi, N.J. and Katnani, H.A. "Interactions of eye and eyelid movements." In: Oxford Handbook of Eye Movements, edited by S. P. Liversedge, I. D. Gilchrist and S. Everling, (in press) 2011.
Bechara, B.P. and Gandhi, N.J. Matching the oculomotor drive during head-restrained and head-unrestrained gaze shifts in monkey. Journal of Neurophysiology, 104: 811-28, 2010.
Anderson, S.R., Porrill, J., Sklavos, S., Gandhi, N.J., Sparks, D.L. and Dean, P. Dynamics of primate oculomotor plant revealed by effects of abducens microstimulation. Journal of Neurophysiology, 101: 2907-2923, 2009.
Walton, M.M.G., Bechara, B.P. and Gandhi, N.J. Effects of reversible inactivation of superior colliculus on head movements. Journal of Neurophysiology, 99: 2479-2495, 2008. [PDF]
Miller, D.M., Cotter, L.A., Gandhi, N.J., Schor, R.H., Cass, S.P., Huff, N.O., Raj, S.G., Shulman, J.A. and Yates, B.J. Responses of caudal vestibular nucleus of conscious cats to rotations in vertical planes, before and after a bilateral vestibular neurectomy. Experimental Brain Research, 188: 175-186, 2008.
Walton, M.M.G., Bechara, B.P. and Gandhi, N.J. Role of the primate superior colliculus in the control of head movements. Journal of Neurophysiology, 98: 2022-2037, 2007. [PDF]