Morphological Correlates of Imprinting
A particular region of the chick brain is critically involved in the storage of information acquired through the learning process of imprinting (Horn, 1981; 1985; and this volume). The region is the intermediate part of the medial hyperstriatum ventrale (IMHV). There is an increased incorporation of [14C]uracil into RNA in this region after chicks have been trained by exposing them to an artificial imprinting stimulus (Horn et al., 1979). This result extended earlier studies which demonstrated that, in chicks trained in this way, there is an increased incorporation of [3H]lysine into proteins in the forebrain roof which contains IMHV (Bateson et al., 1972). The results together suggest that exposure to an imprinting stimulus leads to a change in the metabolism of protein, possibly in protein synthesis, within IMHV. These findings are consistent with the hypothesis that information storage in the brain involves changes in synaptic connections (Tanzi, 1893; Cajal, 1911; Hebb, 1949). However, the biochemical findings provide only indirect evidence for such changes. A direct test of the hypothesis is to determine whether such changes can be demonstrated in a brain region critical for storage. We have therefore used quantitative electron microscopical techniques to investigate the effects of imprinting on the structure of synapses in the IMHV of the domestic chick.
KeywordsDendritic Spine Postsynaptic Density Hemispheric Asymmetry Domestic Chick Chick Brain
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- Bradley, P., 1982, Development of two regions of the chick telencephalon, Neurosci. Lett., 10:588.Google Scholar
- Bradley, P., 1983, Development of dendritic trees in a region of the chick brain involved in a learning process, Fidia Research Series, Frontiers in Neuroscience, Abstract book no. 1:149.Google Scholar
- Bradley, P., Davies, D. C. and Horn, G., 1985, Connections of the hyperstriatum ventrale of the domestic chick (Gallus domesticus), J. Anat., in press.Google Scholar
- Bradley, P. and Horn, G., 1982, A Golgi analysis of the hyperstriatum ventrale in the chick, J. Anat., 134:599.Google Scholar
- Cajal, S. R., 1911, in: “Histologie due système nerveux de l’homme et des vertébrés”, Vol. 2, pp. 886–890, Maloine, Paris. (Republished 1955, Instituto Ramon y Cajal, Madrid.Google Scholar
- Gray, E. G., 1959, Axo-somatic and aco-dendritic synapses of the cerebral cortex: an electron microscope study, J. Anat. (Lond.), 93:420.Google Scholar
- Hebb, D. O., 1949, “The organization of behavior”, John Wiley, New York.Google Scholar
- Horn, G., 1962, Some neural correlations of perception, in: “Viewpoints in biology”, J. D. Carthy and C. L. Duddington, eds., 1:242.Google Scholar
- Horn, G., Bradley, P. and McCabe, B. J. (1985), Changes in the structure of synapses associated with learning, in preparation.Google Scholar
- Tanzi, E., 1893, I fatti e le induzioni nell’ odierna istologia del sistema nervoso, Riv. sper. Freniat. Med. leg. Alien. ment., 19:419.Google Scholar