Presynaptic Control of Afferent Input During Real Locomotion in Rats
Studies were carried out on dorsal root potential (DRP) and dorsal root antidromic action potentials (AAPs) during two types of locomotion (swimming and stepping), which could be distinguished by the intensity of their afferent inputs (AI).
AAPs were taken to be an index to the level of depolarization of low-threshold afferent fibres and DRP, to that of high-threshold ones. During single swimming or stepping locomotor cycles, two DRP and AAP maxima, were found to be associated with the stance (or retraction) and swing phases. The values of AAPs and DRP and the intensity of AI during locomotion and passive hindlimb movements, respectively, were found to be clearly correlated. No dependence between intensity of depolarization of afferent fibres and efferent output was observed during real locomotion, contrary to what was observed during passive hindlimb movement.
It was concluded that DRP and AAPs during real locomotion are initiated mainly by influences from peripheral afferents.
KeywordsDorsal Root Tibialis Anterior Stance Phase Afferent Input Swing Phase
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- Bayev, K. V., 1980, Polarization of lumbar primary afferent terminals during fictitious locomotion, Neirofiziologiva. 12: 481–488.Google Scholar
- Bayev, K. V., and Esipenko, V. B., 1985, Primary afferent depolarization in lumbosacral spinal cord during real locomotion, Neirofiziologiya. 17: 119–121.Google Scholar
- Brooks, C. M. C., and Koizumi, K. 1956, Origin of the dorsal root reflex, J. Neurophysiol., 19: 61–74.Google Scholar
- Bulgakova, N., V. Pilyavsky, and A. L, Yakhnitsa, I. A., 1985, Phase-dependent modulation of antidromic spike potentials in rat dorsal root during locomotion, Neirofiziologiva. 17: 707–710.Google Scholar
- Roberts, H. T., and Wallis, D., 1978, Dorsal and ventral root potentials recorded in vivo by the sucrose-gap method. J. Physiol., 277: 42–43.Google Scholar
- Schmidt, R. F., 1973, Control of the access of afferent activity to somatosensory pathways, in: “Handbook of Sensory Physiology”, Berlin: Springer. 2: 151–206.Google Scholar
- Shik, M. L., and Orlovsky, G. N., 1976, Neurophysioloy of locomotion automatism, Physiol., Rev. 56: 465–501.Google Scholar
- Yakhnitsa, I. A., Pilyavsky, A. I., and Bulgakova, N. V., 1985, Investigation of different kinds of locomotor movements in rats, Neirofiziologiva. 17: 183–189.Google Scholar