One of the great challenges in neurobiology is to understand how sensory and motor systems are integrated to produce behavior. The juxtaposition of cells with sensory and motor properties has made the superior colliculus a fruitful model for studying this process. By applying methods new to the study of the superior colliculus, including in vitro whole-cell patch-clamp recording and photostimulation, we are analyzing for the first time at the cellular level the intrinsic circuitry that links its sensory and motor functions. By filling the cells during recording with neuronal tracers and by pre-labeling them with retrogradely transported tracers, their physiology is correlated with their morphology and connections. =Using this approach, we demonstrated that the superficial collicular layer, which encodes the location of visual stimuli, sends excitatory signals to a deeper layer of premotor cells, which generates commands for visually guided shifts in the direction of gaze. The premotor layer also receives a dense cholinergic input that arises from the same brainstem cells that modulate the flow of sensory information through the visual part of the thalamus to the cortex. Our first Specific Aim is to test the idea that this cholinergic input coordinates the enhancement of sensory signals transmitted to the cortex with the initiation of orienting movements toward visual stimuli. Our second Specific Aim is to test the idea that modulation of premotor activity by long-range inhibition - between the right and left colliculi and between rostral fixation and caudal gaze shifting neurons - permits the activation of premotor cells that command head and eye movements toward visual stimuli in one direction while attenuating the activity of premotor cells that would command competing movements toward stimuli in other directions. These experiments will contribute to our understanding of sensorimotor functions in the normal and diseased brain.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY008233-17
Application #
7171771
Study Section
Visual Sciences B Study Section (VISB)
Program Officer
Oberdorfer, Michael
Project Start
1989-08-01
Project End
2007-12-31
Budget Start
2007-01-01
Budget End
2007-12-31
Support Year
17
Fiscal Year
2007
Total Cost
$336,464
Indirect Cost
Name
Duke University
Department
Biology
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
Phongphanphanee, Penphimon; Mizuno, Fengxia; Lee, Psyche H et al. (2011) A circuit model for saccadic suppression in the superior colliculus. J Neurosci 31:1949-54
Isa, Tadashi; Hall, William C (2009) Exploring the superior colliculus in vitro. J Neurophysiol 102:2581-93
Lee, Psyche H; Sooksawate, Thongchai; Yanagawa, Yuchio et al. (2007) Identity of a pathway for saccadic suppression. Proc Natl Acad Sci U S A 104:6824-7
Prochnow, N; Lee, P; Hall, W C et al. (2007) In vitro properties of neurons in the rat pretectal nucleus of the optic tract. J Neurophysiol 97:3574-84
Lee, Psyche; Hall, William C (2006) An in vitro study of horizontal connections in the intermediate layer of the superior colliculus. J Neurosci 26:4763-8
Helms, Matthew C; Ozen, Gulden; Hall, William C (2004) Organization of the intermediate gray layer of the superior colliculus. I. Intrinsic vertical connections. J Neurophysiol 91:1706-15
Lee, P H; Schmidt, M; Hall, W C (2001) Excitatory and inhibitory circuitry in the superficial gray layer of the superior colliculus. J Neurosci 21:8145-53
Schmidt, M; Boller, M; Ozen, G et al. (2001) Disinhibition in rat superior colliculus mediated by GABAc receptors. J Neurosci 21:691-9
Ozen, G; Augustine, G J; Hall, W C (2000) Contribution of superficial layer neurons to premotor bursts in the superior colliculus. J Neurophysiol 84:460-71
Pettit, D L; Helms, M C; Lee, P et al. (1999) Local excitatory circuits in the intermediate gray layer of the superior colliculus. J Neurophysiol 81:1424-7

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