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A survey of spinal dorsal horn neurones encoding the spatial organization of withdrawal reflexes in the rat.
- Source :
-
Experimental brain research [Exp Brain Res] 1995; Vol. 106 (1), pp. 19-27. - Publication Year :
- 1995
-
Abstract
- The withdrawal reflex pathways to hindlimb muscles have an elaborate spatial organization in the rat. In short, the distribution of sensitivity within the cutaneous receptive field of a single muscle has a spatial pattern that is a mirror image of the spatial pattern of the withdrawal of the skin surface ensuing on contraction in the respective muscle. In the present study, a search for neurones encoding the specific spatial input-output relationship of withdrawal reflexes to single muscles was made in the lumbosacral spinal cord in halothane/nitrous oxide-anaesthetized rats. The cutaneous receptive fields of 147 dorsal horn neurones in the L4-5 segments receiving a nociceptive input and a convergent input from A and C fibres from the hindpaw were studied. The spatial pattern of the response amplitude within the receptive fields of 118 neurones was quantitatively compared with those of withdrawal reflexes to single muscles. Response patterns exhibiting a high similarity to those of withdrawal reflexes to single muscles were found in 27 neurones located in the deep dorsal horn. Twenty-six of these belonged to class 2 (responding to tactile and nociceptive input) and one belonged to class 3 (responding only to nociceptive input). None of the neurones tested (n = 20) with reflex-like response patterns could be antidromically driven from the upper cervical cord, suggesting that they were spinal interneurones. With some overlap, putative interneurones of the withdrawal reflexes to the plantar flexors of the digits, the plantar flexors of the ankle, the pronators, the dorsiflexors of the ankle, and a flexor of the knee, were found in succession in a mediolateral direction.(ABSTRACT TRUNCATED AT 250 WORDS)
- Subjects :
- Animals
Axons physiology
Foot innervation
Hindlimb physiology
Male
Neural Pathways cytology
Neural Pathways physiology
Physical Stimulation
Rats
Rats, Wistar
Skin Physiological Phenomena
Spinal Cord cytology
Thalamus cytology
Thalamus physiology
Neurons physiology
Reflex physiology
Space Perception physiology
Spinal Cord physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0014-4819
- Volume :
- 106
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Experimental brain research
- Publication Type :
- Academic Journal
- Accession number :
- 8542974
- Full Text :
- https://doi.org/10.1007/BF00241353