Neurons in the Pontomedullary Reticular Formation Signal Posture and Movement Both as an Integrated Behavior and Independently
Open Access
- 1 October 2008
- journal article
- research article
- Published by American Physiological Society in Journal of Neurophysiology
- Vol. 100 (4), 2235-2253
- https://doi.org/10.1152/jn.01381.2007
Abstract
We have previously suggested that the discharge characteristics of some neurons in the pontomedullary reticular formation (PMRF) are contingent on the simultaneous requirement for activity in both ipsilateral flexor muscles and contralateral extensors. To test this hypothesis we trained cats to stand on four force platforms and to perform a task in which they were required to reach forward with one forelimb or the other and depress a lever. As such the task required the cat to make a flexion movement followed by an extension in the reaching limb while maintaining postural support by increasing extensor muscle tonus in the supporting limbs. We recorded the activity of 131 neurons from the PMRF of three cats during left, ipsilateral reach. Of these, 86/131 (66%) showed a change in discharge frequency prior to the onset of activity in one of the prime flexor muscles and 43/86 (50%) showed a bimodal pattern of discharge in which activity decreased during the lever press. Among the remaining cells, 28/86 (33%) showed maintained activity throughout the reach and the lever press. Most cells showed a broadly similar pattern of discharge during reaches with the right, contralateral limb. We suggest these results support the view that a population of neurons within the PMRF contributes to the control of movement in one forelimb and the control of posture in the other forelimb as a coordinated unit. Another population of neurons contributes to the control of postural support independently of the nature of the activity in the reaching limb.Keywords
This publication has 37 references indexed in Scilit:
- Bilateral Spike-Triggered Average Effects in Arm and Shoulder Muscles from the Monkey Pontomedullary Reticular FormationJournal of Neuroscience, 2007
- Descending Signals From the Pontomedullary Reticular Formation Are Bilateral, Asymmetric, and Gated During Reaching Movements in the CatJournal of Neurophysiology, 2006
- Independent and Convergent Signals From the Pontomedullary Reticular Formation Contribute to the Control of Posture and Movement During Reaching in the CatJournal of Neurophysiology, 2004
- Motor Outputs From the Primate Reticular Formation to Shoulder Muscles as Revealed by Stimulus-Triggered AveragingJournal of Neurophysiology, 2004
- Lumbar commissural interneurons with reticulospinal inputs in the cat: Morphology and discharge patterns during fictive locomotionJournal of Comparative Neurology, 2004
- Strategies for the Integration of Posture and Movement During Reaching in the CatJournal of Neurophysiology, 2003
- Multi-segmental innervation of single pontine reticulospinal axons in the cervico-thoracic region of the cat: Anterograde PHA-L tracing studyJournal of Comparative Neurology, 1997
- The effect of different descending systems on flexor and extensor activity during locomotionBrain Research, 1972
- THE FUNCTIONAL ORGANIZATION OF THE MOTOR SYSTEM IN THE MONKEYBrain, 1968
- THE FUNCTIONAL ORGANIZATION OF THE MOTOR SYSTEM IN THE MONKEYBrain, 1968