The Journal of physiology
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The Journal of physiology · Mar 1973
The effect of increasing the innervation field sizes of nerves on their reflex response time in salamanders.
1. A simple quantitative measure was sought which could describe the relationship between reflex coupling in the spinal cord of salamanders and the peripheral innervation fields of the nerves from which the reflexes were elicited.2. In decerebrate salamanders reflex responses were recorded between pairs of cut hind limb nerves. ⋯ In spite of the increased peripheral fields of both these nerves, there was no change in the S/R times between them, or between any other pair of limb nerves on the operated side.8. The decrease in the S/R times between the 15th and 17th nerves was only observed where the stimulated nerve had increased its peripheral limb innervation field. The possible causes and significance of this shortening reflex response times are discussed in the context of an apparently functionally appropriate adaptation in the spinal cord.
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The Journal of physiology · Mar 1973
The organization of primary afferent depolarization in the isolated spinal cord of the frog.
1. The organization of primary afferent depolarization (PAD) produced by excitation of peripheral sensory and motor nerves was studied in the frog cord isolated with hind limb nerves.2. Dorsal root potentials from sensory fibres (DR-DRPs) were evoked on stimulation of most sensory nerves, but were largest from cutaneous, joint and flexor muscle afferents. ⋯ This system may have a role in modulating the ballistic movement of the frog. DR-DRPs, on the contrary, are widespread in origin and distribution. PAD from sensory fibres may function to sharpen contrast between incoming afferent information.