Subject(s)
Electrooculography , Eye Movements , Psychophysiology/methods , Visual Pathways/physiology , Visual Perception/physiology , Animals , Cats , Computers , Evoked Potentials, Visual , Female , Male , SaccadesSubject(s)
Corpus Callosum/anatomy & histology , Reticular Formation/anatomy & histology , Sensation/physiology , Spinal Cord/anatomy & histology , Thalamus/anatomy & histology , Afferent Pathways/anatomy & histology , Animals , Brain Mapping , Cats , Conditioning, Operant/physiology , Electrophysiology , Kinesthesis/physiology , Pain/physiopathology , Somatosensory Cortex/physiologyABSTRACT
In cats with section of classic, contralateral somatosensory pathways of the fore-leg at the midbrain level an instrumental defensive reflex "to this leg" can be elaborated. This fact suggests that the intact ipsilateral afferent somatosensory pathways of the brain-stem transmit kinsthetic excitations. The electrophysiological study (acute experiments under nembutal anesthesia) of somatosensory projections of the fore-leg, contralateral to the midbrain section, revealed bilateral evoked responses in the somato-sensory cortical areas with a latency of 18-20 msec. These responses evidence bilateral afferent projections of the ipsilateral part of the spinoreticulo-thalamic system. They constitute the functional basis for the formation of this conditioned instrumental defensive reflex. The lemniscal system as well as the ipsilateral part of spino-reticulo-thalamic system send bilateral afferent projections to the somatosensory structures of the brain.