Pattern of development of the callosal transfer of visual information to cortical areas 17 and 18 in the cat

摘要: The aim of this study was to investigate the development visual callosal transfer in normally reared cat. Two- nine-week-old kittens and adults (used as controls) underwent section optic chiasm. Three days later, animals were placed under anaesthesia paralysed; unit activities recorded from cortical areas 17 18 white matter one hemisphere. units tested for their responses stimulation each eye successively. Out 1036 neurons, 185 could be activated through contralateral explored cortex via transfer. Most them also driven ipsilateral ‘direct ’ geniculo-cortical pathway. For aged >2 weeks, virtually all these located at 17/18 border zone, with a majority supragranular layers. When corpus callosum, they displayed receptive fields either on central vertical meridian field or hemifield cortex. Such extension into well disparities binocular decreased age, while spontaneous activity, strength response, orientation selectivity ability respond slits moving middle-range velocity increased. main conclusion is that transient projections described by anatomists, which are present until 3 months do not achieve supraliminar synaptic contacts parts other than least 12 after birth. However young displays some characteristics disappear age.