Summary
27 cells in the S I group I projection area of the cerebral cortex, identified as activated by group I afferent fibres by electrical stimulation of the deep radial nerve, were examined by natural stimulation in 4 awake cats.
Sixty-four percent of the cells responded to wrist and/or digital ventroflexion only. Another 28% of the cells responded also to elbow flexion or extension. Only one cell responded to stretch of antagonistic muscles.
Half of the cells responded to pulling of only one out of four available muscle tendons of wrist and digital dorsiflexors. The rest of the cells responded to pulling of two adjacent tendons.
All cells tested responded to light tapping stimulation of skin areas overlying the muscles providing excitation, presumably as a result of mechanical stimulus spread to sensitive muscle spindles. 20% of the cells responded to deflection of hairs located on the paw.
The receptive fields obtained were compared with those obtained in the cortex and at lower levels of the pathway with electrical nerve stimulation on nembutalized animals.
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Rosén, I., Asanuma, H. Natural stimulation of group I activated cells in the cerebral cortex of the awake cat. Exp Brain Res 16, 247–254 (1973). https://doi.org/10.1007/BF00233329
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DOI: https://doi.org/10.1007/BF00233329