| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20982-4435
Submitted 20 December 2002; accepted in final form 5 May 2003
The visual world presents multiple potential targets that can be brought to the fovea by saccadic eye movements. These targets produce activity at multiple sites on a movement map in the superior colliculus (SC), an area of the brain related to saccade generation. The saccade made must result from competition between the populations of neurons representing these many saccadic goals, and in the present experiments we used multiple moveable microelectrodes to follow this competition. We recorded simultaneously from two sites on the SC map where each site was related to a different saccade target. The two targets appeared in rapid sequence, and the monkey was rewarded for making a saccade toward the one appearing first. Our study concentrated on trials in which the monkey made strongly curved saccades that were directed first toward one target and then toward the other. These curved saccades activated both sites on the SC map as they veered from one target to the other. The major finding was that the strongly curved saccades were preceded by sequential activity in the two neurons as indicated by three observations: the firing rate for the neuron related to the first target reached its peak earlier than did the rate of the neuron for the second target; the timing of the peak activity of the two neurons was related to the beginning and end of the saccade curvature; a weighted vector-average model based on the activity of the two neurons predicted the timing of saccade curvature. Straight averaging saccades ended between the targets so that they did not go to either target, and they were accompanied by simultaneous rather than sequential activation of the two neurons. Thus when multiple populations of neurons are active on the SC movement map, the resulting saccade is determined by the relative timing of the activity in the populations as well as their magnitude. In contrast, SC activity at the two sites did not predict the final direction of the saccade, and several control experiments found insufficient activity at other sites on the SC map to account for that final direction. We conclude that the SC neuronal activity predicts the timing of the saccade curvature, but not the final direction of the trajectory. These observations are consistent with SC activity being critical in selecting the goal of the saccade, but not in determining the exact trajectory.
This article has been cited by other articles:
|
|
 |
|
  B. Kim and M. A. Basso Saccade Target Selection in the Superior Colliculus: A Signal Detection Theory Approach J. Neurosci., March 19, 2008; 28(12): 2991 - 3007. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-H. Song, N. Takahashi, and R. M. McPeek Target Selection for Visually Guided Reaching in Macaque J Neurophysiol, January 1, 2008; 99(1): 14 - 24. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Murthy, S. Ray, S. M. Shorter, E. G. Priddy, J. D. Schall, and K. G. Thompson Frontal Eye Field Contributions to Rapid Corrective Saccades J Neurophysiol, February 1, 2007; 97(2): 1457 - 1469. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. J. H. Ludwig, J. W. Mildinhall, and I. D. Gilchrist A Population Coding Account for Systematic Variation in Saccadic Dead Time J Neurophysiol, January 1, 2007; 97(1): 795 - 805. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Ramat, R. J. Leigh, D. S. Zee, and L. M. Optican What clinical disorders tell us about the neural control of saccadic eye movements Brain, January 1, 2007; 130(1): 10 - 35. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. M. McPeek Incomplete Suppression of Distractor-Related Activity in the Frontal Eye Field Results in Curved Saccades J Neurophysiol, November 1, 2006; 96(5): 2699 - 2711. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. McSorley, P. Haggard, and R. Walker Time Course of Oculomotor Inhibition Revealed by Saccade Trajectory Modulation J Neurophysiol, September 1, 2006; 96(3): 1420 - 1424. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H.H.L.M. Goossens and A. J. Van Opstal Dynamic Ensemble Coding of Saccades in the Monkey Superior Colliculus J Neurophysiol, April 1, 2006; 95(4): 2326 - 2341. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Li and M. A. Basso Competitive Stimulus Interactions within Single Response Fields of Superior Colliculus Neurons J. Neurosci., December 7, 2005; 25(49): 11357 - 11373. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. M. OPTICAN Sensorimotor Transformation for Visually Guided Saccades Ann. N.Y. Acad. Sci., April 1, 2005; 1039(1): 132 - 148. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. M. G. Walton, D. L. Sparks, and N. J. Gandhi Simulations of Saccade Curvature by Models That Place Superior Colliculus Upstream From the Local Feedback Loop J Neurophysiol, April 1, 2005; 93(4): 2354 - 2358. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Watanabe, Y. Kobayashi, Y. Inoue, and T. Isa Effects of Local Nicotinic Activation of the Superior Colliculus on Saccades in Monkeys J Neurophysiol, January 1, 2005; 93(1): 519 - 534. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Cavanaugh and R. H. Wurtz Subcortical Modulation of Attention Counters Change Blindness J. Neurosci., December 15, 2004; 24(50): 11236 - 11243. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Arai, R. M. McPeek, and E. L. Keller Properties of Saccadic Responses in Monkey When Multiple Competing Visual Stimuli Are Present J Neurophysiol, February 1, 2004; 91(2): 890 - 900. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
