Summary
In normal adult cats three regions with callosal projections from the contralateral visual areas 17, 18, and 19 have been identified at the lateral border of area 18 by degeneration techniques (Sanides, 1978). The visuotopic distribution of these callosal patches has now been investigated by combining anatomical with physiological techniques. The centers of the receptive fields recorded in the callosal patches are located on or close to the vertical meridian in the contralateral hemifield reaching eccentricities of about 15 deg. Some of these fields are of extraordinary size crossing the vertical meridian and covering large areas of the ipsilateral hemifield. On the other hand, receptive fields recorded from the acallosal parts of lateral area 18 may reach eccentricities of more than 50 deg. Thus, the callosal patches of lateral area 18 are wedged in between parts of lateral area 18 which represent the periphery of the contralateral hemifield. It is concluded that the retinotopic arrangement at lateral area 18 (the second visual area) distinguishes this area fundamentally from area 17, the primary visual area.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Albus, K., Beckmann, R.: The second and the third visual area of the cat: interindividual variability in retinotopic arrangement and cortical location. J. Physiol. (Lond.) (in press)
Berlucchi, G.: Anatomical and physiological aspects of visual functions of corpus callosum. Brain Res 37, 371–392 (1972)
Choudhury, B.P., Whitteridge, D., Wilson, M.E.: The functions of the callosal connections of the visual cortex. Quart. J. Exp. Physiol. 50, 214–219 (1965)
Donaldson, I.M.G., Whitteridge, D.: The nature of the boundary between cortical visual areas II and III in the cat. Proc. R. Soc. Lond. B. 199, 445–462 (1977)
Ebner, F.F., Myers, R.E.: Distribution of corpus callosum and anterior commissure in cat and racoon. J. Comp. Neurol. 124, 353–366 (1965)
Fink, R.P., Heimer, L.: Two methods for selective impregnation of degenerating axons and their synaptic endings in the central nervous system. Brain Res. 4, 369–374 (1967)
Garey, L.J., Jones, E.G., Powell, T.P.S.: Interrelationship of striate and extrastriate cortex with the primary relay sites of the visual pathway. J. Neurol. Neurosurg. Psychiat. 31, 135–157 (1968)
Hubel, D.H., Wiesel, T.N.: Receptive fields and functional architecture in two nonstriate visual areas (18 and 19) of the cat. J. Neurophysiol. 28, 229–289 (1965)
Hubel, D.H., Wiesel, T.N.: Cortical and callosal connections concerned with the vertical meridian of visual fields in the cat. J. Neurophysiol. 30, 1561–1573 (1967)
Innocenti, G.M., Fiore, L.: Morphological correlates of visual field transformation in the corpus callosum. Neurosci. Lett. 2, 245–252 (1976)
Palmer, L.A., Rosenquist, A.C., Tusa, R.J.: The retinotopic organization of lateral suprasylvian visual areas in the cat. J. Comp. Neurol. 177, 237–253 (1976)
Sanides, D.: The retinotopic distribution of visual callosal projections in the suprasylvian visual areas compared to the classical visual areas (17, 18, 19) in the cat. Exp. Brain Res. 33, 435–443 (1978)
Shatz, C.J.: Anatomy of interhemispheric connections in the visual system of Boston Siamese and ordinary cats. J. Comp. Neurol. 173, 497–518 (1977a)
Shatz, C.J.: Abnormal interhemispheric connections in the visual system of Boston Siamese cats: A physiological study. J. Comp. Neurol. 171, 229–246 (1977b)
Shoumura, K.: An attempt to relate the origin and distribution of commissural fibers to the presence of large and medium pyramids in layer III in the cats visual cortex. Brain Res. 67, 13–25 (1974)
Tusa, R.J., Palmer, L.A., Rosenquist, A.C.: The retinotopic organization of area 17 (striate cortex) in the cat. J. Comp. Neurol. 177, 213–236 (1978)
Tusa, R.J., Rosenquist, A.C., Palmer, L.A.: Retinotopic organization of areas 18 and 19 in the cat. J. Comp. Neurol. 185, 657–678 (1979)
Author information
Authors and Affiliations
Additional information
After completion of this manuscript, Dr. Detlev Sanides died on June 3, 1979
Rights and permissions
About this article
Cite this article
Sanides, D., Albus, K. The distribution of interhemispheric projections in area 18 of the cat: Coincidence with discontinuities of the representation of the visual field in the second visual area (V2). Exp Brain Res 38, 237–240 (1980). https://doi.org/10.1007/BF00236745
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00236745