Summary
In the thalamic ventrobasal complex (VB) of the cat, effects of electrical stimulation of the pyramidal tract (PT) upon activities of 112 relay cells and 18 internuncial cells were examined. Single PT shocks to the cerebral peduncle elicited short-latency discharges in 31 relay cells (mean latency, 1.4±0.5 msec). When weak PT stimuli were employed as conditioning shocks, facilitatory effects upon responses to medial lemniscal (ML) stimulation were observed. It was revealed that VB relay cells were excited monosynaptically via collaterals of the fast PT fibers. Among 31 PT-excited cells 22 were fired by movements of joints (joint-movement units) and they made up 88% of all the joint-movement units. A majority of the relay cells responding to stimulation of hairs (hair units) did not receive excitatory effects from PT, except some special ones which represented long hairs at the distal or proximal end of the forearm-forepaw.
In 44 relay cells repetitive PT shocks suppressed both evoked responses to ML stimulation and spontaneous discharges for 70–100 msec. Of these, 34 were hair units. The PT-induced inhibition in the hair units increased as their receptive fields shifted from the trunk towards the digits. Some intracellular recordings showed that the PT-induced inhibition was due to IPSPs generated disynaptically.
Among 18 interneurons presumed to be inhibitory 10 responded with short latencies to PT stimulation. These were mostly the interneurons which presumably subserve the recurrent collateral inhibition in VB.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Andersen, P., Eccles, J.C., Sears, T.A.: The ventro-basal complex of the thalamus: Types of cells, their responses and their functional organization. J. Physiol. (Lond.) 174, 370–399 (1964a)
Andersen, P., Eccles, J.C., Schmidt, R.F., Yokota, T.: Slow potential wave produced in the cuneate nucleus by cutaneous volleys and by cortical stimulation. J. Neurophysiol. 27, 78–91 (1964b)
Andersen, P., Eccles, J.C., Schmidt, R.F., Yokota, T.: Identification of relay cells and interneurons in the cuneate nucleus. J. Neurophysiol. 27, 1080–1095 (1964c)
Andersen, P., Junge, K., Sveen, O.: Cortico-fugal facilitation of thalamic transmission. Brain Behav. Evol. 6, 170–184 (1972)
Andersson, S.A., Landgren, S., Wolsk, D.: The thalamic relay and cortical projection of Group I muscle afferents from the forelimb of the cat. J. Physiol. (Lond.) 183, 576–591 (1966)
Brown, A.G., Iggo, A.: A quantitative study of cutaneous receptors and afferent fibers in the cat and rabbit. J. Physiol. (Lond.) 193, 707–733 (1967)
Brown, A.G., Gordon, G., Kay, R.H.: A study of single axons in the cat's medial lemniscus. J. Physiol. (Lond.) 236, 225–246 (1974)
Burchfiel, J.E., Duffy, F.H.: Corticofugal influence upon cat thalamic ventrobasal complex. Brain Res. 70, 395–411 (1974)
Chambers, W.W., Liu, C.N., McCouch, G.P.: Inhibition of the dorsal column nuclei. Exp. Neurol. 7, 12–23 (1963)
Creutzfeldt, O., Fuster, J.M., Herz, A., Straschill, M.: Some problems of the information transmission in the visual system. In: Eccles, J.C. (Ed.): Brain and Conscious Experience, pp. 138–164. Berlin-Heidelberg-New York: Springer 1966
Dawson, G.D.: The effects of cortical stimulation on transmission through the cuneate nucleus in the anesthetized rat. J. Physiol. (Lond.) 142, 2–3 (1958)
Gordon, G., Jukes, M.G.M.: Descending influences on the extroceptive organization of the cat's gracile nucleus. J. Physiol. (Lond.) 173, 291–319 (1964)
Iwama, K., Yamamoto, C.: Impulse transmission of thalamic somatosensory relay nuclei as modified by electrical stimulation of the cerebral cortex. Jap. J. Physiol. 11, 169–182 (1961)
Jabbur, S.J., Towe, A.L.: Analysis of the antidromic cortical response following stimulation at the medullary pyramids. J. Physiol. (Lond.) 155, 148–160 (1961a)
Jabbur, S.J., Towe, A.L.: Cortical excitation of neurons in dorsal column nuclei of cat, including an analysis of pathways. J. Neurophysiol. 24, 499–509 (1961b)
Levitt, M., Carreras, M., Liu, C.N., Chambers, W.W.: Pyramidal and extrapyramidal modulation of somatosensory activity in gracile and cuneate nuclei. Arch. ital. Biol. 102, 197–229 (1964)
Magni, P., Melzack, R., Moruzzi, G., Smith, C.J.: Direct pyramidal influences on the dorsal-column nuclei. Arch. ital. Biol. 97, 357–377 (1959)
Mountcastle, V.B., Powell, T.P.S.: Central mechanisms subserving position sense and kinesthesis. Bull. Johns Hopk. Hosp. 105, 173–200 (1959)
Ogden, T.E.: Cortical control of thalamic somato-sensory relay nuclei. Electroenceph. clin. Neurophysiol. 12, 621–634 (1960)
Rosén, I.: Excitation of Group I activated thalamocortical relay neurons in the cat. J. Physiol. (Lond.) 205, 237–255 (1969)
Shimazu, H., Yanagisawa, N., Garoutte, B.: Cortico-pyramidal influences on thalamic somato-sensory transmission in the cat. Jap. J. Physiol. 15, 101–124 (1965)
Straile, W.E.: Sensory hair follicles in mammalian skin. Amer. J. Anat. 106, 133–147 (1960)
Takahashi, K.: Slow and fast groups of pyramidal tract cells and their respective membrane properties. J. Neurophysiol. 28, 908–924 (1965)
Towe, A.L.: Somatosensory cortex: Descending influences on ascending systems. In: Handbook of sensory physiology, vol. II, pp. 701–718. Ed. by A. Iggo. Berlin-Heidelberg-New York: Springer 1973
Towe, A.L., Jabbur, S.J.: Cortical inhibition of neurons in dorsal column nuclei of cat. J. Neurophysiol. 24, 488–498 (1961)
Tsumoto, T.: Characteristics of the thalamic ventrobasal relay neurons as a function of conduction velocities of medial lemniscal fibers. Exp. Brain Res. 21, 211–224 (1974)
Tsumoto, T., Nakamura, S.: Inhibitory organization of the thalamic ventrobasal neurons with different peripheral representations. Bxp. Brain Res. 21, 195–210 (1974)
Wiesendanger, M.: The pyramidal tract. Recent investigations on its morphology and function. Ergebn. Physiol. 61, 72–136 (1969)
Winter, D.L.: Nucleus gracilis of cat. Functional organization and corticofugal effects. J. Neurophysiol. 28, 48–70 (1965)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Tsumoto, T., Nakamura, S. & Iwama, K. Pyramidal tract control over cutaneous and kinesthetic sensory transmission in the cat thalamus. Exp Brain Res 22, 281–294 (1975). https://doi.org/10.1007/BF00234770
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00234770