The goal of this research is to analyze the effects of eye movements and eye position on the electrical activity of neurons in primary visual cortex (VI) and the second visual cortical area (V2) of macaque monkeys. During the viewing of natural scenes the brain must separate the modulatory influences of eye movements from the signals that code properties of objects in the world. A major theme is the effects of the drifts and the small saccades of fixational eye movements. These miniature eye movements help to maintain the visibility of stationary visual stimuli. Some cortical cells appear to respond preferentially to the slow component of fixational eve movements (drifts) while others respond to the faster component (saccades). For comparison, the effects of larger voluntary saccades that scan the visual world will be studied. Recent psychophysical evidence indicates that voluntary saccades selectively suppress the visual input of the magnocellular system. These results imply that as saccades become larger, there may be a switch from excitatory to inhibitory effects on cortical neurons. In addition, large saccades have the consequence of taking the eye to a new position in the orbit. To judge the position of objects in the world, the brain must maintain information about the position of the eye in the orbit to combine it with location of the image on the retina. The spatial gain fields of V1 and V2 neurons that contribute to this computation will be measured. Recording sites will be localized to specific anatomical compartments to identify the regional networks and the pathways within which the recorded neurons are embedded. The results will be relevant to human visual perception, as well as in vivo imaging of human visual function.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY012243-04
Application #
6518605
Study Section
Visual Sciences B Study Section (VISB)
Program Officer
Oberdorfer, Michael
Project Start
1999-05-01
Project End
2003-01-31
Budget Start
2002-05-01
Budget End
2003-01-31
Support Year
4
Fiscal Year
2002
Total Cost
$162,823
Indirect Cost
Name
Schepens Eye Research Institute
Department
Type
DUNS #
City
Boston
State
MA
Country
United States
Zip Code
02114
Snodderly, D Max (2016) A physiological perspective on fixational eye movements. Vision Res 118:31-47
Medina, Antonio; Greene, Peter R (2015) Progressive Myopia and Lid Suture Myopia are Explained by the Same Feedback Process: a Mathematical Model of Myopia. J Nat Sci 1:
Przybyszewski, Andrzej W; Kagan, Igor; Snodderly, D Max (2014) Primate area V1: largest response gain for receptive fields in the straight-ahead direction. Neuroreport 25:1109-15
Gur, Moshe; Snodderly, D Max (2008) Physiological differences between neurons in layer 2 and layer 3 of primary visual cortex (V1) of alert macaque monkeys. J Physiol 586:2293-306
Kagan, Igor; Gur, Moshe; Snodderly, D Max (2008) Saccades and drifts differentially modulate neuronal activity in V1: effects of retinal image motion, position, and extraretinal influences. J Vis 8:19.1-25
Gur, Moshe; Snodderly, D Max (2007) Direction selectivity in V1 of alert monkeys: evidence for parallel pathways for motion processing. J Physiol 585:383-400
Gur, Moshe; Snodderly, D Max (2006) High response reliability of neurons in primary visual cortex (V1) of alert, trained monkeys. Cereb Cortex 16:888-95
Gur, Moshe; Kagan, Igor; Snodderly, D Max (2005) Orientation and direction selectivity of neurons in V1 of alert monkeys: functional relationships and laminar distributions. Cereb Cortex 15:1207-21
Kagan, Igor; Gur, Moshe; Snodderly, D Max (2002) Spatial organization of receptive fields of V1 neurons of alert monkeys: comparison with responses to gratings. J Neurophysiol 88:2557-74
Snodderly, D M; Kagan, I; Gur, M (2001) Selective activation of visual cortex neurons by fixational eye movements: implications for neural coding. Vis Neurosci 18:259-77