A critical question that must be answered before we understand the control of sensoryguided saccades is that of how the spatial (anatomical) code of saccade direction and amplitude contained in the superior colliculus (SC) is transformed into the temporal signals required by motoneurons for the generation of saccadic movements. The long-range goals of the proposed research are directed toward the solution of this improtant problem. Chronic unit recording, microstimulation , and reversible deactivation methods will be used to study the role of the SC and brainstem recipients of inputs from the SC in the control of saccadic eye movements. More specifically, the goals of the project are to: a) Perform a detailed analysis of the alterations in saccade direction and amplitude occurring during reversible deactivation of small regions of the SC before and after unilateral removal of the frontal eye fields (FEFs). b) Characterize the saccaderelated discharges of neurons in tectorecipient areas by: 1) plotting the movement fields of neurons displaying saccaderelated activity; 2) quantifying the relationship between saccaderelated neural activity and saccadic velocity (vectorial velocity as well as component velocity); 3) determining the effects of varying the initial fixation position upon saccaderelated bursts; and 4) determining the effects of deactiviation of neurons in the SC upon the discharge of neurons with saccaderelated activity. c) Examine the connections between SC and neurons in PPRF, cMRF and NRTP using orthodromic and antidromic stimulation methods. d) Determine whether or not specific functional classes of neurons isolated in the PPRF, cMRF and NRTP receive inputs from specific types of collicular neurons using dual recording methods and cross correlation analysis. e) Study the effects of localized reversible deactiviation of small regions in the PPRF, cMRF and NRTP upon the latency, duration, direction, velocity, and amplitude of saccadic eye movements.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
4R37EY001189-20
Application #
3483884
Study Section
Special Emphasis Panel (NSS)
Project Start
1989-08-01
Project End
1997-07-31
Budget Start
1992-08-01
Budget End
1993-07-31
Support Year
20
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Type
Schools of Arts and Sciences
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Quinet, Julie; Goffart, Laurent (2015) Cerebellar control of saccade dynamics: contribution of the fastigial oculomotor region. J Neurophysiol 113:3323-36
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Gandhi, Neeraj J; Barton, Ellen J; Sparks, David L (2008) Coordination of eye and head components of movements evoked by stimulation of the paramedian pontine reticular formation. Exp Brain Res 189:35-47
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Gandhi, Neeraj J; Sparks, David L (2007) Dissociation of eye and head components of gaze shifts by stimulation of the omnipause neuron region. J Neurophysiol 98:360-73
Sparks, David L; Hu, Xintian (2006) Saccade initiation and the reliability of motor signals involved in the generation of saccadic eye movements. Novartis Found Symp 270:75-88; discussion 88-91, 108-13
Walton, Mark M G; Sparks, David L; Gandhi, Neeraj J (2005) Simulations of saccade curvature by models that place superior colliculus upstream from the local feedback loop. J Neurophysiol 93:2354-8
Goffart, Laurent; Chen, Longtang L; Sparks, David L (2004) Deficits in saccades and fixation during muscimol inactivation of the caudal fastigial nucleus in the rhesus monkey. J Neurophysiol 92:3351-67
Barton, Ellen J; Nelson, Jon S; Gandhi, Neeraj J et al. (2003) Effects of partial lidocaine inactivation of the paramedian pontine reticular formation on saccades of macaques. J Neurophysiol 90:372-86
Sparks, David L; Gandhi, Neeraj J (2003) Single cell signals: an oculomotor perspective. Prog Brain Res 142:35-53

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