Experiments were performed in 4 macaque monkeys to ascertain whether 1) the body midline representation in the trunk zone of area SI is subserved by neurones with bilateral receptive fields and, 2) the callosal connections in the trunk zone are confined specifically to the midline representation. The map of the trunk was outlined by exploring with microelectrodes the receptive fields of neurones in the appropriate region of both areas 3b and 1 whereas the distribution in these areas of the callosal terminals and neurones was investigated by injecting horseradish peroxidase in the contralateral homotopic cortex. Areas 3b and 1 contain two complete and separate representations of the trunk. At the 3b-1 border, neurones were found responding to bilateral stimulation of the dorsal surface of the trunk (dorsal midline zone) whereas neurones responding to bilateral stimulation of the surface of the anterior trunk and of the abdomen (ventral midline zone) were found in the rostral and caudal parts of area 3b and 1, respectively. Callosal terminals and neurones labelled with horseradish peroxidase were overwhelmingly grouped within the dorsal and ventral midline zones.
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Con il contributo del Ministero per i Beni e le Attività Culturali