Journal of Neurophysiology, Vol 47, Issue 5 827-844, Copyright © 1982 by APS

ARTICLES

Activity of omnipause neurons in alert cats during saccadic eye movements and visual stimuli

C. Evinger, C. R. Kaneko and A. F. Fuchs

1. In the cats trained to follow a target spot with their eyes, activity was recorded from omnipause neurons (OPNs). OPNs discharge at a relatively high steady tonic rate (50-130 spikes/s) during visual fixation and smooth-pursuit eye movements but exhibit a complete cessation of discharge that begins before saccades in any direction. They are located in a compact region of the dorsal pontine tegmentum near the midline, just rostral to the abducens nucleus. 2. The average duration of the horizontal or vertical component of a saccade increases monotonically with pause duration, but a given pause duration is associated with a large range of individual saccade parameters and the timing of the pause, such as the latency from the pause onset to saccade onset or the interval from the maximum saccade velocity to the end of the pause, is no better. However, OPNs can be divided into two distinct groups on the basis of the timing of the pause relative to the parameters of the saccade. One group ceases discharging 32.4 +/- 4.6 ms, on average, before the saccade, while the second pauses 18.2 +/- 3.4 ms before the saccade. 3. Microstimulation at the site of OPNs affects the occurrence and trajectory of saccades but not smooth pursuit or fixation. Sustained electrical stimulation (20 micro A) lasting several seconds prevents the occurrence of saccades while brief trains (10-60 ms), timed to occur early in the saccade, interrupt it in midflight for the duration of the train. The latency to the interruption is about 26 ms. These data support the view that OPNs tonically inhibit the saccadic machinery between saccades and must be turned off to allow a saccade to occur. 4. Almost every (65 of 69) feline OPN exhibited a brief transient increase in activity for visual stimuli moving in any direction with a wide range of velocities. A moving 1 degree spot was generally more effective than a moving full-field, striped background. All units also showed a transient increase in firing when the spot was turned either on or off. Receptive fields plotted with the spot were greater than 250 deg2 and always included the area centralis. Two-thirds of the cells tested also responded to auditory stimuli. 5. Interaction between the excitatory visual input and the saccade-related pause was tested by comparing OPN activity and the saccadic trajectory during eye movements in the dark versus the light and by presenting brief flashes of light during a saccade. During saccades in the dark, the steady firing of OPNs was less than during saccades in the light. Only by stabilizing a flashed spot of light to occur on the area centralis at the beginning of the saccade was it possible to activate an OPN artificially to interrupt the saccade in midflight. Therefore, rather than being instrumental in specifically controlling the saccade trajectory, the visual input, along with the auditory and other sensory inputs, probably serves, under normal visual conditions, to help establish the tonic rate of OPNs. 6...

This article has been cited by other articles:

				M. Takahashi, Y. Sugiuchi, and Y. Shinoda Commissural Mirror-Symmetric Excitation and Reciprocal Inhibition Between the Two Superior Colliculi and Their Roles in Vertical and Horizontal Eye Movements J Neurophysiol, November 1, 2007; 98(5): 2664 - 2682. [Abstract] [Full Text] [PDF]

				C. K. Rodgers, D. P. Munoz, S. H. Scott, and M. Pare Discharge Properties of Monkey Tectoreticular Neurons J Neurophysiol, June 1, 2006; 95(6): 3502 - 3511. [Abstract] [Full Text] [PDF]

				M. Takahashi, Y. Sugiuchi, Y. Izawa, and Y. Shinoda Commissural Excitation and Inhibition by the Superior Colliculus in Tectoreticular Neurons Projecting to Omnipause Neuron and Inhibitory Burst Neuron Regions J Neurophysiol, September 1, 2005; 94(3): 1707 - 1726. [Abstract] [Full Text] [PDF]

				Y. Sugiuchi, Y. Izawa, M. Takahashi, J. Na, and Y. Shinoda Physiological Characterization of Synaptic Inputs to Inhibitory Burst Neurons From the Rostral and Caudal Superior Colliculus J Neurophysiol, February 1, 2005; 93(2): 697 - 712. [Abstract] [Full Text] [PDF]

				C. Busettini and L. E. Mays Pontine Omnipause Activity During Conjugate and Disconjugate Eye Movements in Macaques J Neurophysiol, December 1, 2003; 90(6): 3838 - 3853. [Abstract] [Full Text] [PDF]

				K. Kornylo, N. Dill, M. Saenz, and R. J. Krauzlis Canceling of Pursuit and Saccadic Eye Movements in Humans and Monkeys J Neurophysiol, June 1, 2003; 89(6): 2984 - 2999. [Abstract] [Full Text] [PDF]

				A. Bergeron and D. Guitton In Multiple-Step Gaze Shifts: Omnipause (OPNs) and Collicular Fixation Neurons Encode Gaze Position Error; OPNs Gate Saccades J Neurophysiol, October 1, 2002; 88(4): 1726 - 1742. [Abstract] [Full Text] [PDF]

				B. D. Corneil, E. Olivier, and D. P. Munoz Neck Muscle Responses to Stimulation of Monkey Superior Colliculus. I. Topography and Manipulation of Stimulation Parameters J Neurophysiol, October 1, 2002; 88(4): 1980 - 1999. [Abstract] [Full Text] [PDF]

				E. M. Reingold and D. M. Stampe Saccadic Inhibition in Voluntary and Reflexive Saccades J. Cogn. Neurosci., April 1, 2002; 14(3): 371 - 388. [Abstract] [Full Text] [PDF]

				N. J. Gandhi and E. L. Keller Comparison of Saccades Perturbed by Stimulation of the Rostral Superior Colliculus, the Caudal Superior Colliculus, and the Omnipause Neuron Region J Neurophysiol, December 1, 1999; 82(6): 3236 - 3253. [Abstract] [Full Text] [PDF]

				N. J. Gandhi and E. L. Keller Activity of the Brain Stem Omnipause Neurons During Saccades Perturbed by Stimulation of the Primate Superior Colliculus J Neurophysiol, December 1, 1999; 82(6): 3254 - 3267. [Abstract] [Full Text] [PDF]

				K. Yoshida, Y. Iwamoto, S. Chimoto, and H. Shimazu Saccade-Related Inhibitory Input to Pontine Omnipause Neurons: An Intracellular Study in Alert Cats J Neurophysiol, September 1, 1999; 82(3): 1198 - 1208. [Abstract] [Full Text] [PDF]

				M. Pare and D. Guitton Brain Stem Omnipause Neurons and the Control of CombinedEye-Head Gaze Saccades in the Alert Cat J Neurophysiol, June 1, 1998; 79(6): 3060 - 3076. [Abstract] [Full Text] [PDF]

				S. Everling, M. Pare, M. C. Dorris, and D. P. Munoz Comparison of the Discharge Characteristics of Brain Stem Omnipause Neurons and Superior Colliculus Fixation Neurons in Monkey: Implications for Control of Fixation and Saccade Behavior J Neurophysiol, February 1, 1998; 79(2): 511 - 528. [Abstract] [Full Text] [PDF]

				K. E. Cullen and D. Guitton Analysis of Primate IBN Spike Trains Using System Identification Techniques. II. Relationship to Gaze, Eye, and Head Movement Dynamics During Head-Free Gaze Shifts J Neurophysiol, December 1, 1997; 78(6): 3283 - 3306. [Abstract] [Full Text] [PDF]

				M. J. Mustari, A. F. Fuchs, and M. Pong Response Properties of Pretectal Omnidirectional Pause Neurons in the Behaving Primate J Neurophysiol, January 1, 1997; 77(1): 116 - 125. [Abstract] [Full Text] [PDF]

				M. A. Basso and C. Evinger An Explanation for Reflex Blink Hyperexcitability in Parkinson's Disease. II. Nucleus Raphe Magnus J. Neurosci., November 15, 1996; 16(22): 7318 - 7330. [Abstract] [Full Text] [PDF]