Ricerche morfologiche sulle connessioni callosali dell'area somestesica seconda della Scimmia (Macacus Irus)

Manzoni, Tullio   ; Barbaresi, Paolo   ; Conti, Fiorenzo

Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali, Série 8, Tome 75 (1983) no. 6, pp. 369-375

Résumé

In six Java monkeys (Macacus Irus) experiments of neuronal labelling by retrograde transport of horseradish peroxidase (HRP) were performed in order to study the callosal connections of the hand sensory projection field of the second somatosensory area (SII) in the parietal operculum. Under ketamine anaesthesia, 3 monkeys received a single HRP injection ($0.5 \mu l$) and the other 3 monkeys multiple injections ($5-8; 0.5 \mu l$ each) within the deep cortex forming the upper bank of the Sylvian Sulcus. In the first group of 3 animals, the site of enzyme delivery was selected by recording preliminarily with tungsten microelectrodes neuronal responses to somatic sensory stimulation of the hand. Following a single HRP injection in the parietal operculum, HRP retrogradely-labelled cells were found in the first somatosensory area (SI) of the ipsilateral hemisphere (associative cells) and in the thalamic nuclei ventralis postero-inferior and pulvinar oralis. In the contralateral hemisphere, labelled cells (callosal cells) were found mainly in area SII, clustered in a region homotopic to the injected cortex, and a few also in area SI. Following multiple HRP injections which involved large regions of the parietal operculum, labelled cells were found in the ipsilateral area SI and in the following thalamic nuclei: ventralis postero-inferior, pulvinar oralis and medialis, posterior complex, ventralis postero-medialis, and ventral part of ventralis postero-lateralls. In the contralateral hemisphere, numerous callosal neurones were present in several areas of the parietal operculum (areas 3-1-2, SII, 7b and retroinsular) and few also in area SI. Callosal cells of area SII were located in cortical regions corresponding topographically to the hand representation zone.

Bibliographie

[1] Adams J.C. (1977) - Technical considerations on the use of horseradish peroxidase as a neuronal marker, «Neuroscience», 2, 141-145.

[2] Burton H. e Jones E.G. (1976) - The posterior thalamic region and its cortical projection in new world and old world monkeys, «J. Comp. Neurol.», 168, 249-302.

[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] Carreras M. e Anderson S.A. (1963) - Functional properties of neurones of the anterior ectosylvian gyrus of the cat, «J. Neurophysiol.», 26, 100-126.

[5] Friedman D.P., Jones E.G. e Burton H. (1980) - Representation pattern in the second somatic sensory area of the monkey cerebral cortex, «J. Comp. Neurol.», 192, 21-41.

[6] Garcha H.S., Ettlinger G. e Maccabe J.J. (1982) — Unilateral removal of the second somatosensory projection cortex in the monkey: evidence for cerebral predominance?, «Brain», 105, 787-810.

[7] Innocenti G.M., Manzoni T. e Spidalieri G. (1973) - Relevance of the callosal transfer in defining the peripheral reactivity of somesthetic cortical neurones, «Arch. Ital. Biol.», 111, 187-221.

[8] Innocenti G.M., Manzoni T. e Spidalieri G. (1974) - Patterns of somesthetic messages transferred through the corpus callosum, «Exp. Brain Res.», 19, 447-466.

[9] Jones E.G. e Powell T.P.S. (1969) - Connexions of the somatic sensory cortex of the Rhesus Monkey II. Contralateral cortical connexionsy. «Brain», 92, 717-730.

[10] Jones E.G. e Powell T.P.S. (1970) - Connexions of the somatic sensory cortex of the Rhesus monkey. III. Thalamic connexions, «Brain», 93, 37-56.

[11] Manzoni T., Barbaresi P. e Conti F. - Correlazione tra campi recettivi periferici e neuroni di proiezione callosale delle aree somestesiche prima e seconda della scimmia (Macacus Irus), «Atti Accad. Naz. Lincei», in stampa.

[12] Mountcastle V.B. e Henneman E. (1952) - The representation of tactile sensibility in the thalamus of the monkey, «J. Comp. Neurol.», 97, 409-440.

[13] Pandya D.N. e Vignolo L.A. (1969) - Interhemispheric projections of the parietal lobe in the Rhesus Monkey, «Brain Res.», 15, 49-65.

[14] Robinson C.J. e Burton H. (1980) - Somatotopographic organization in the second somatosensory area of M. fascicularis, «J. Comp. Neurol.», 192, 43-67.

[15] Robinson C.J. e Burton H. (1980) - Organization of somatosensory receptive fields in cortical areas 7b, retroinsular postauditory andgranular insula of M.fascicularis, «J. Comp. Neurol.», 192, 69-92.

[16] Teitelbaum H., Sharpless S.K. e Byck R. (1968) - Role of somatosensory cortex in interhemispheric transfer of tactile habits, «J. Comp. Physiol. Psychol », 66, 623-632.

[17] Whitsel B.L., Petrucelli L.M. e Werner G. (1969) - Symmetry and connectivity in the map of the body surface in somatosensory area II ofprimates, «J. Neurophysiol.», 32, 170-183.

[18] Woolsey C.N. (1943) — Second somatic receiving areas in the cerebral cortex of the cat, dog and monkey, «Fed. Proc.», 2, 55-56.