Spatial patterns of reflex evoked by pressure stimulation of the foot pads in cats
1. The spatial patterns of reflexes elicited by localized pressure stimulation of the foot skin were analysed by recording electromyographic activities of various hindlimb muscles or muscle nerve discharges in cats anaesthetized with sodium pentobarbitone. 2. Reflex discharges evoked by stimulation...
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Veröffentlicht in: | The Journal of physiology 1990-01, Vol.420 (1), p.471-487 |
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Sprache: | eng |
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Zusammenfassung: | 1. The spatial patterns of reflexes elicited by localized pressure stimulation of the foot skin were analysed by recording
electromyographic activities of various hindlimb muscles or muscle nerve discharges in cats anaesthetized with sodium pentobarbitone.
2. Reflex discharges evoked by stimulation of the central pad occurred mainly in physiological toe extensors located in the
foot. Stimulus-response relationships of single motor units revealed characteristically wide ranges of graded response and
recruitment. 3. Within the central pad, the strongest excitation was evoked from the central lobe and was distributed to extensors
of all four toes. Excitation from the medial and the lateral lobes was usually asymmetrical and weaker in toe muscles of the
stimulated side. It is suggested that the weakness was in part due to concomitant inhibition. 4. Stimulation of a toe pad
caused marked suppression of central pad-evoked activity of toe extensors with a highly specific spatial pattern. The inhibition
was strongest in extensors of its own toe, and gradually weaker in the more distant toes. Weak excitation was occasionally
evoked in extensors of the most medial or lateral toes, when the most lateral or the most medial toe-pad, respectively, was
stimulated. 5. A similar pattern of relfex to that from the toe pad was evoked from the claw base and the hairy toe dorsum
of each digit. 6. Reflex effects, both inhibitory and excitatory, from the central and toe pads, claw bases and toe dorsum
were maintained during prolonged stimuli, indicating that slowly adapting receptors contributed to these reflexes. 7. It is
concluded that stimulation of localized skin areas of the foot, particularly the pads, evokes highly specialized reflexes,
which may be important in controlling movements of individual digits. |
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ISSN: | 0022-3751 1469-7793 |
DOI: | 10.1113/jphysiol.1990.sp017923 |