Neuroscience 2003 Abstract
| Presentation Number: | 277.12 |
|---|---|
| Abstract Title: | Bulbospinal pathways activating locomotor-like activity in the <I>in vitro</I> neonatal rat spinal cord: chemical versus electrical stimulation of the brainstem. |
| Authors: |
Schmidt, B. J.*1
; Zaporozhets, E.1
; Jordan, L. M.1
1Physiology, Univ. of Manitoba, Winnipeg, Canada |
| Primary Theme and Topics |
Motor Systems - Pattern Generation and Locomotion |
| Session: |
277. Pattern Generation: Development & Modulation Poster |
| Presentation Time: | Sunday, November 9, 2003 4:00 PM-5:00 PM |
| Location: | Morial Convention Center - Hall F-I, Board # G34 |
| Keywords: | network, interneuron, brainstem, locomotion |
We previously showed that propriospinal pathways in the cervicothoracic region contribute to the descending activation of locomotor-like activity in the in vitro neonatal rat spinal cord (SFN 27:297.11,2001); these experiments involved chemical activation of the brainstem using a combination of 5-HT, NMDA and bicuculline. The present series attempts to further characterize bulbospinal pathways activating locomotor-like rhythms, using a combination of bath partitions, selected spinal cord lesions, and neurochemical manipulation of propriospinal transmission. Brain stem-spinal cord preparations were isolated from rats (days 1-6) and subjected to either chemical or electrical stimulation of the brainstem. Lumbar ventral root locomotor-like rhythms induced by chemical, but not electrical, stimulation of the brainstem were abolished by bilateral ventral white matter lesions of the thoracic cord, or by application of calcium-free bath solutions or an NMDA receptor antagonist (AP5) to the cervicothoracic region. Locomotor-like activity evoked by electrical, but not chemical, stimulation of the brainstem persisted despite thoracic cord sectioning which left intact only the lateral white matter on one side. Lumbar rhythmic activity in response to brainstem electrical stimulation was better developed when hemicord lesions were made at rostral rather than caudal thoracic levels. These results suggest that a) descending activation of the locomotor network in response to chemical activation of the brainstem is critically dependent on propriospinal transmission, b) electrical stimulation recruits long direct projections that are capable of transmitting the locomotor command signal independent of propriospinal pathways and c) essential portions of the propriospinal, but not direct, locomotor command pathway travel in the ventral white matter regions.
Supported by NIH - NS40903-02.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2003 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2003. Online.
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