Journal of Neurophysiology, Vol 72, Issue 1 14-30, Copyright © 1994 by APS

ARTICLES

Primate rubromotoneuronal cells: parametric relations and contribution to wrist movement

K. Mewes and P. D. Cheney
Department of Physiology, University of Kansas Medical Center, Kansas City 66160.

1. Fifty-nine rubromotoneuronal (RM) cells were identified in two rhesus monkeys on the basis of their postspike facilitation (PSpF) of rectified electromyographic (EMG) activity. These cells were studied in relation to a step tracking task requiring wrist movements between fixed target zones in flexion and extension. Movement away from a 0 position was opposed by spring-like loads (auxotonic). Additionally, nine cells were evaluated using an isometric task. Neuronal discharge could be divided into three basic components: background discharge in the absence of movement, phasic modulation during movement, and tonic modulation during sustained holding against external loads. 2. Four basic patterns of RM cell activity were observed in relation to ramp-and-hold wrist movements: phasic-tonic (44%), pure phasic (22%), pure tonic (2%), and unmodulated (24%). The discharge of unmodulated cells did not covary with movement parameters but, as with other RM cells, background discharge did increase in association with task performance. 3. The phasic discharge of RM cells led to the onset of target muscle EMG activity by an average of 89 +/- 82 ms (mean +/- SD, n = 104) in extensors and 88 +/- 74 ms (n = 30) in flexors. Target muscles are defined as ones showing PSpF of EMG activity. It was found that 94% of extensor and 87% of flexor RM cells discharged before or synchronous with the onset of target muscle EMG activity. 4. Thirty-one RM cells (53%) showed a tonic increase in cell activity during the static hold phase of the task. Twenty-three of these were tested for relations to static torque. Fifteen extension related cells and one flexion cell had significant, positive regression slopes for the relation between tonic discharge rate and static torque. The mean rate-torque slope for extension related cells was 160 Hz/Nm and 103 Hz/Nm for flexion related cells. These mean slopes are about one-third those of corticomotoneuronal (CM) cells. 5. Cell discharge rate was correlated with velocity and rate of change of torque (dT/dt) for 32 RM cells with a phasic component of discharge during movement. The peak increase in phasic discharge above tonic firing rate (PDI, peak dynamic index) was significantly correlated only with velocity in eight cells and only with dT/dt in five cells. The phasic discharge of four additional cells was correlated with both velocity and dT/dt, but for three of these cells, the correlation was stronger for velocity. The mean slope for the relation between velocity and PDI was 0.31 Hz.deg-1.s-1.(ABSTRACT TRUNCATED AT 400 WORDS)

This article has been cited by other articles:

				M. H. Schieber and G. Rivlis Partial Reconstruction of Muscle Activity From a Pruned Network of Diverse Motor Cortex Neurons J Neurophysiol, January 1, 2007; 97(1): 70 - 82. [Abstract] [Full Text] [PDF]

				A. T. Dypvik and B. H. Bland Functional Connectivity Between the Red Nucleus and the Hippocampus Supports the Role of Hippocampal Formation in Sensorimotor Integration J Neurophysiol, October 1, 2004; 92(4): 2040 - 2050. [Abstract] [Full Text] [PDF]

				S. Lavoie and T. Drew Discharge Characteristics of Neurons in the Red Nucleus During Voluntary Gait Modifications: A Comparison with the Motor Cortex J Neurophysiol, October 1, 2002; 88(4): 1791 - 1814. [Abstract] [Full Text] [PDF]

				P. L. E. Van Kan and M. L. McCurdy Contribution of Primate Magnocellular Red Nucleus to Timing of Hand Preshaping During Reaching to Grasp J Neurophysiol, March 1, 2002; 87(3): 1473 - 1487. [Abstract] [Full Text] [PDF]

				P. L. E. Van Kan and M. L. McCurdy Role of Primate Magnocellular Red Nucleus Neurons in Controlling Hand Preshaping During Reaching to Grasp J Neurophysiol, April 1, 2001; 85(4): 1461 - 1478. [Abstract] [Full Text] [PDF]

				C. Hager-Ross and M. H. Schieber Quantifying the Independence of Human Finger Movements: Comparisons of Digits, Hands, and Movement Frequencies J. Neurosci., November 15, 2000; 20(22): 8542 - 8550. [Abstract] [Full Text] [PDF]

				A. Belhaj-Saif and P. D. Cheney Plasticity in the Distribution of the Red Nucleus Output to Forearm Muscles After Unilateral Lesions of the Pyramidal Tract J Neurophysiol, May 1, 2000; 83(5): 3147 - 3153. [Abstract] [Full Text] [PDF]

				B. J. McKiernan, J. K. Marcario, J. H. Karrer, and P. D. Cheney Correlations Between Corticomotoneuronal (CM) Cell Postspike Effects and Cell-Target Muscle Covariation J Neurophysiol, January 1, 2000; 83(1): 99 - 115. [Abstract] [Full Text] [PDF]

				M.-J. Rho, S. Lavoie, and T. Drew Effects of Red Nucleus Microstimulation on the Locomotor Pattern and Timing in the Intact Cat: A Comparison With the Motor Cortex J Neurophysiol, May 1, 1999; 81(5): 2297 - 2315. [Abstract] [Full Text] [PDF]

				S. I. Perlmutter, M. A. Maier, and E. E. Fetz Activity of Spinal Interneurons and Their Effects on Forearm Muscles During Voluntary Wrist Movements in the Monkey J Neurophysiol, November 1, 1998; 80(5): 2475 - 2494. [Abstract] [Full Text] [PDF]

				M. A. Maier, S. I. Perlmutter, and E. E. Fetz Response Patterns and Force Relations of Monkey Spinal Interneurons During Active Wrist Movement J Neurophysiol, November 1, 1998; 80(5): 2495 - 2513. [Abstract] [Full Text] [PDF]

				B. J. McKiernan, J. K. Marcario, J. H. Karrer, and P. D. Cheney Corticomotoneuronal Postspike Effects in Shoulder, Elbow, Wrist, Digit, and Intrinsic Hand Muscles During a Reach and Prehension Task J Neurophysiol, October 1, 1998; 80(4): 1961 - 1980. [Abstract] [Full Text] [PDF]

				L. E. Miller and T. Sinkjaer Primate Red Nucleus Discharge Encodes the Dynamics of Limb Muscle Activity J Neurophysiol, July 1, 1998; 80(1): 59 - 70. [Abstract] [Full Text] [PDF]

				A. Belhaj-Saif, J. H. Karrer, and P. D. Cheney Distribution and Characteristics of Poststimulus Effects in Proximal and Distal Forelimb Muscles From Red Nucleus in the Monkey J Neurophysiol, April 1, 1998; 79(4): 1777 - 1789. [Abstract] [Full Text] [PDF]