Conditioning pp 223-231 | Cite as

Classical Conditioning Mediated by the Red Nucleus in the Cat

  • Nakaakira Tsukahara
Part of the Advances in Behavioral Biology book series (ABBI, volume 26)


We have attempted to develop a behavioral and neuronal model for the study of classical conditioning using the corticorubrospinal system. A conditioned stimulus (CS) was applied to the cerebral peduncle (CP) in cats which had lesions that interrrupted the corticofugal fibers caudal to the red nucleus. The unconditioned stimulus (US) was an electric shock to the skin of the forelimb that produced flexion of the limb. After pairing of the CS and US in close temporal association, an initially ineffective stimulus to the cerebral peduncle was found to give rise to flexion of the elbow. Extinction of this conditioned response could be achieved by applying the CS alone, or by reversing the sequence of the stimuli (US-CS:backward pairing). The US when used alone did not produce an increase in the effectiveness of the CS, and pairing a fixed CS with a US at random intervals did not produce any increase in performance in response to the CS. In these respects, the observed behavioral modification has the features of associative conditioning.

Because both the threshold for and strength of elbow flexion induced by stimulation of the nucleus interpositus of the cerebellum were identical in experimental and control animals, it is unlikely that the interpositorubrospinal system is the neuronal site of behavioral change. Instead, since the conditioned response is most probably mediated the corticorubrospinal system, it is likely that a modification of the corticorubral synapses underlies the change in behavior. Extracellular recording from red nucleus cells in unanesthetized cats has shown that stimulation of the CP induces a greater degree of excitation in the red nucleus in animals that have undergone conditioning than control animals. (The control group contained cats which had received no training, or those which had received backwardly paired stimulation, or random CS-US pairing).


Conditioned Stimulus Unconditioned Stimulus Classical Conditioning Elbow Flexion Cerebral Peduncle 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Fujito, Y., Tsukahara, N., Oda, Y., and Yoshida, M., 1981, Formation of functional synapses in the adult feline red nucleus from the cerebrum following cross-innvervation of forelimb flexor and extensor nerves. II. Analysis of newly-appeared postsynaptic potentials. Exp. Brain Res. (in press).Google Scholar
  2. Illert, M., Lundberg, A., and Tanaka, R., 1976, Integration in descending motor pathways controlling the forelimb in the cat.a. Convergence on neurones mediating disynaptic corticomotoneuronal excitation. Exp. Brain Res. 26: 521.Google Scholar
  3. Murakami, F., Tsukahara, N., and Fujito, Y., 1977, Analysis of unitary EPSPs mediated by the newly-formed cortico-rubral synapses after lesion of the nucleus interpositus of the cerebellum. Exp. Brain Res. 30: 233.Google Scholar
  4. Oda, Y., Kuwa, K., Miyasaka, S., and Tsukahara, N. Modification of rubral unit activities during classical conditioning of the cat. (in preparation).Google Scholar
  5. Smith, A. M., 1970, The Effects of rubral lesions and stimulation on conditioned forelimb flexion responses in the cat. Physiol. Behay. 5: 1121.Google Scholar
  6. Tsukahara, N., and Fujito, Y., 1976, Physiological evidence of formation of new synapses from cerebrum in the red nucleus following cross-union of forelimb nerves. Brain Res. 106: 184.PubMedCrossRefGoogle Scholar
  7. Tsukahara, N., and Kosaka, K., 1968, The mode of cerebral excitation of red nucleus neurons. Exp. Brain Res. 5: 102.Google Scholar
  8. Tsukahara, N., Hultborn, H., Murakami, F., and Fujito, Y., 1975, Electrophysiological study of formation of newGoogle Scholar
  9. synapses and collateral sprouting in red nucleus neurons after partial denervation. J. Neurophysiol. 38: 1359.Google Scholar
  10. Tsukahara, N., Oda, Y., and Notsu, T., 1981, Classical conditioning mediated by the red nucleus in the cat. J. Neurosci., 1: 72.PubMedGoogle Scholar
  11. Tsukahara, N., Fujito, Y., Oda, Y., and Maeda, J. Formation of functional synapses in adult red nucleus from the cerebrum following cross-innervation of forelimb flexor and extensor nerves. I. Appearance of new synaptic potentials Ex. Brain Res. (in press).Google Scholar

Copyright information

© Springer Science+Business Media New York 1982

Authors and Affiliations

  • Nakaakira Tsukahara
    • 1
  1. 1.Department of Biophysical Engineering Faculty of Engineering Science Osaka UniversityToyonaka, Osaka and National Institute for Physiological SciencesOkazakiJapan

Personalised recommendations