Correlazione tra la distribuzione dei neuroni callosali e rappresentazione della linea mediana nell'area somestesica prima (SI)

Manzoni, Tullio ; Barbaresi, Paolo ; Caminiti, Roberto ; Conti, Fiorenzo

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti, Tome 68 (1980), p. 585-593 / Harvested from Biblioteca Digitale Italiana di Matematica

Résumé

Experiments have been carried out in order to study in the first somato-sensory area (SI) the relationships between the topography of callosal neurones and the physiological map of the trunk. Horseradish peroxidase (HRP) was injected into the posterior sygmoid gyrus of one hemisphere of 20 adult cats. On 11 of them, the contralateral homotopic cortex was explored with tungsten microelectrodes on the day after HRP delivery. Neurones retrogradely labelled by HRP (callosal neurones) were grouped within two regions located, respectively, in the rostral and caudal zones of the exteroceptive trunk map. In both regions, callosal neurones were found mainly in layer III and many also in layer VI, especially following large HRP delivery in the contralateral area SI. Callosal neurones located in layer III were mostly pyramidal, those of layer VI, pyramidal and non-pyramidal. The rostral group of callosal neurones overlaps the representation of the dorsal body midline and the caudal group that of the ventral body midline. The cortex intervening between these two zones has few or no callosal cells and receives the projections from the lateral surface of the trunk. According to the electrophysiological data, neurones located within the two midline zones have a bilateral receptive field, straddling either the back or the ventral surface of the trunk. In the other zones of the trunk and proximal limb map receptive fields were contralateral. It is concluded that callosal connectivity is strictly related to the bilaterality of receptive fields.

Détail

Publié le : 1980-06-01

Bibliographie

[1] Adams, J.C. (1977) - Technical considerations in the use of horseradish peroxidase as a neural marker, «Neurosci Abs.», 2, 141.

[2] Berlocchi, G. (1972) - Anatomical and physiological aspects of visual function of corpus callosum, «Brain Res.», 37, 371-392.

[3] Caminiti, R., Innocenti, G.M. e Manzoni, T. (1979) - The anatomical substrate of callosal messages from SI and SII in the cat, «Exp. Brain Res.», 35, 295-314.

[4] Choudhury, B.P., Witteridge, D. e Wilson, M.E. (1965) - The function of the callosal connections of the visual cortex, «Quart. J. Exp. Physiol.», 50, 214-219.

[5] Donaldson, L., Hand, P.J. e Morrison, A.R. (1975) - Cortical-thalamic relationships in the rat, «Exp. Neurol.», 47, 448-458.

[6] Garcia-Rill, E. e Dubrowsky, B. (1973) - Topographical organization of visual input to precruciate motor cortex of cat, «Brain Res.», 56, 151-163.

[7] Garey, L.J., Jones, E.G. e Powell, T.P.S. (1968) - Interrelationships of striate and extrastriate cortex with primary relay sites of the visual pathways, «J. Neurol. Neurosurg. Psychiat.», 31, 135—157.

[8] Hassler, R. e Muhs-Clement, K. (1964) - Architektonischer Aufbau des sensomotorischen und parietalen Cortex der Katze, «J. Hirnforsch», 6, 377-420.

[9] Hubel, D.H. e Wiesel, T.N. (1967) - Cortical and callosal connections concerned with the vertical meridian of visual fields in the cat, «J. Neurophysiol.», 30, 1561-1573.

[10] Innocenti, G.M. e Fiore, L. (1976) - Morphological correlates of visual field transformation in the corpus callosum, «Neurosci. Letters», 2, 245-252.

[11] Innocenti, G.M., Manzoni, T. e Spidalieri, G. (1973) - Relevance of the callosal transfer in defining the peripheral reactivity of somesthesic cortical neurones, «Arch, ital. Biol.», III, 187-221.

[12] Jones, E.G. e Powell, T.P.S. (1968) - The commisural connections of the somatic sensory cortex in the cat, «J. Anat.», 103, 433-455.

[13] Jones, E.G. e Powell, T.P.S. (1969) - Connexions of the somatic sensory cortex of the rhesus monkey. II. Contralateral cortical connections, «Brain», 92, 717-730.

[14] Jones, E.G. e Powell, T.P.S. (1970) - An electron microscopic study of the laminar pattern and mode of termination of afferent fibre pathways in the somatic sensory cortex of the cat, «Phil. Trans. Roy Soc. Lond.», B 257, 45-62.

[15] Manzoni, T. (1976) - Intracortical mechanisms influencing the peripheral reactivity of SII convergence neurones. In: Creutzfeldt O. (Ed.), Afferent and intrinsic organization of laminated structures in the brain, «Exp Brain Res.», Suppl. 1, 431-436.

[16] Manzoni, T., Caminiti, R., Spidalieri, G. e Morelli, E. (1979) - Anatomical and functional aspects of the associative projection from somatic area SI to SII, «Exp. Brain Res.», 34, 453-470.

[17] Mountcastle, V.B. (1957) - Modality and topographic properties of single neurons of cat's somatic sensory cortex, «J. Neurophysiol.», 20, 408-434.

[18] Shatz, C. (1977) - Anatomy of interhemispheric connections in the visual system of Boston Siamese and ordinary cats, «J. Comp. Neurol.», 173, 497-518.

[19] Werner, G. e Whitsel, B.L. (1973) - The functional organization of somatosensory cortex. In: Iggo A. (Ed.), Handbook of sensory physiology, vol. II, Springer, Berlin-Heidelberg-New York, pp. 621-700.