Analisi microfisiologica sui collegamenti intrinseci cortico—corticali tra l'area SI e Varea SII

Caminiti, Roberto ; Manzoni, Tullio ; Spidalieri, Giuseppe

Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali, Série 8, Tome 58 (1975) no. 4, pp. 662-669

Résumé

Microelectrode recordings from the SII cortical area of chloralose-anaesthetized cats have been performed in order to ascertain the peripheral reactivity of the neurones receiving cortico-cortical projections from the ipsilateral SI area. With glass micropipettes, extracellular records were obtained from 64 cells isolated in the forepaw focus, and each one was tested with stimulation both of its peripheral receptive field (PRF) and of the forepaw region of the SI. Twenty-two such units were endowed with very strict, contralateral fields (Group IR), 7 with contralateral wide fields (Group IA), 14 with bilateral fields, either very wide (11 units; Group IIA) or strict (3 units; Group IIR). The remaining 21 neurones, not excitable from the periphery or excited only by peripheral electric shocks, were included in Group III. Upon single-shock stimulation of the ipsilateral SI, excitatory responses of short-latency (range, 1.8-7 msec; mean, 4.16 msec ± 0.15 s.d.) were recorded from 19 units, all excitable from PRF (Group IA: 6 cells; Group IIA: 10 cells; Group IIR: 3 cells). No unit of Group IR and III were seen to react to transcortical impulses. When PRF shocks were applied during subliminal stimulation of ipsilateral SI, a strong facilitatory effect was obtained. Comparison of the latency of the discharges elicited in SII neurones by SI stimulation with the latency of the effects obtained on the same units by stimulation of the ipsilateral thalamic VPL nucleus showed that most of the former effects did not imply any thalamic mediation.