Do Reward and Drive Neurons Exist?
Brain stimulation and lesion studies have shown that a bundle of pathways extending bidirectionally from the medulla to the telencephalon through the lateral hypothalamus may contain the axons of a set of reward neurons. In self-stimulation experiments stimulation of these pathways caused reward behavior; in lesion studies, cutting them suspended it temporarily and modified it permanently. Lesions removing much of the forebrain showed that at least some of the critical neurons did not have their cell bodies in the front end of this system. Other experiments gave strong but not yet compelling evidence that two or three families of catecholamine-containing neurons with cell bodies at the back end of the system and widely broadcast axons might be the neurons in question. “Unit recording” studies pointed to different neurons which monitored the bidirectional bundle in midcourse at the hypothalamic level as being possibly drive neurons. These were active in striving animals, further activated by conditioned stimuli associated with rewards, but silenced by several different kinds of rewards. Indirect evidence suggested that these were excited also by visceral and/or hormonal inputs; and that their axons might become connected during development and learning to cell assemblies in the cortex and basal ganglia, possibly to cell assemblies active at the time of their being “silenced” by rewards. The wide ramifications of the supposed reward axons suggested that besides “inhibiting drives” there might also be other functions. The most likely ones would be to stamp in sensory-motor connections (possibly in the cerebellum), to motivate the “replay” of sequential behavior memories (possibly in the hippocampus), and to “charge” (or connect drives to) cell assemblies active at the time of reward (possibly in the neocortex).
KeywordsConditioned Stimulus Lateral Hypothalamus Medial Forebrain Bundle Instrumental Behavior Drive Behavior
Unable to display preview. Download preview PDF.
- Ahlskog, J. E., and Hoebel, B. G. (1972). Overeating and obesity from damage to a noradrenergic system in the brain. Science 182, 17–27.Google Scholar
- Garcia, J., and Ervin, F. R. (1968). Gustatory-visceral and telereceptor-cutaneous conditioning-Adaptation in internal and external milieus. Commun. Behav. Biol. Part A, 1, 389–415.Google Scholar
- Hamburg, M. D. (1971). Hypothalamic unit activity and eating behavior. Am. J. Physiol. 220, 980–985.Google Scholar
- Ito, M. (1972). Excitability of medial forebrain bundle neurons during self-stimulating behavior. J. Neurophysiol. 35, 652–664.Google Scholar
- Iversen, L. L. (1967). The Uptake and Storage of Noradrenaline in Sympathetic Nerves, Cambridge, England: The University Press.Google Scholar
- Jouvet, M. (1974). Monoaminergic regulation of the sleep-waking cycle in the cat. In:The Neurosciences, Third Study Program, F. O. Schmitt and F. G. Worden (Eds.). MIT Press, Cambridge, Mass., pp. 49–508.Google Scholar
- Kerr, F. W., Triplett, J. N., and Beeler, G. W. (1974). Reciprocal (push-pull) effects of morphine on single units in the ventromedian and lateral hypothalamus and influences on other nuclei; with a comment on methadone effects during withdrawal from morphine. Brain Res. 74, 81–103.CrossRefGoogle Scholar
- Klüver, H., and Bucy, P. C. (1937). Psychic blindness and other symptoms following bilateral temporal lobectomy in rhesus monkey. Am. J. Physiol. 119, 352–353.Google Scholar
- Linseman, M. A., and Olds, J. (1973). Activity changes in rat hypothalamus, preoptic area and striatum associated with Pavlovian conditioning. J. Neurophysiol. 36, 1038–1050.Google Scholar
- Olds, J. (1958). Discussion. In CIBA Foundation Symposium on the Neurological Basis of Behaviour. G. E. W. Wolstenholme and C. M. O’Connor (Eds.). London: Churchill, p. 89.Google Scholar
- Olds, J. (1962). Hypothalamic substrates of reward. Physiol Rev. 42, 554–604.Google Scholar
- Olds, M. E., and Olds, J. (1962). Approach-escape interactions in rat brain. Am. J. Physiol. 203, 803–810.Google Scholar
- Phillis, J. W. (1970). The Pharmacology of Synapses. New York: Pergamon Press.Google Scholar
- Roberts, W. W. (1958). Both rewarding and punishing effects from stimulation of posterior hypothalamus of cat with same electrode at same intensity. J. Comp. Phychol. 51, 400–407.Google Scholar
- Ungerstedt, U. (1971a). Stereotaxic mapping of the monoamine pathways in the rat brain. Acta Physiol Scand. (Suppl. 367), 1–4Google Scholar
- Villabianca, J. (1974). Presentation of films of kittens and cats with bilateral ablations of the caudate nuclei. Conference on Brain Mechanisms in Mental Retardation. Oxnard, California, Jan. 13-16. (Sponsored jointly by MRRC of UCLA and NICHHD, Washington, D. C.).Google Scholar
- Wise, C. D., Berger, B. D., and Stein, L. (1973). Evidence of alpha-noradrenergic reward receptors and serotonergic punishment receptors in the rat brain. Biol Psychiatry 6, 3–21.Google Scholar