An electrophysiological study of thalamo-caudate neurones in the cat Academic Article uri icon


  • Thalamo-caudate projection neurones were identified in cats by antidromic activation from the caudate nucleus, under chloralose anaesthesia or in cerveau isolĂ© preparations. Units in nuclei centralis lateralis, medialis dorsalis, and centrum medianum-parafascicularis responded antidromically to one or more electrodes of a caudate nucleus array at latencies ranging from 0.4 to 16 ms. The responses did not appear to result from stimulus spread to the internal capsule. A separate population of medial thalamic units responded postsynaptically to caudate stimulation, at modal latency exceeding modal antidromic latency by 2 ms. Comparison of apparent conduction velocities for each thalamic nucleus indicated that the postsynaptic responses were activated by collaterals of thalamo-caudate neurones. A proportion of thalamo-caudate neurones responded to somatic stimulation; some of these were inhibited by caudate stimulation, and a few discharged on substantia nigra stimulation. These results demonstrate the possibility of somatic afferent and nigrofugal inputs to the caudate nucleus mediated by neurones of the medial thalamus.

publication date

  • July 1979