Somatosensory units in the cat's intercollicular region.
Sampling of unitary, neural activity was made with tungsten electrodes in the mesencephalon of cats anaesthetized with chloralose. Possible activation was studied with adequate somatosensory, visual and acoustic stimuli as well as electrical nerve stimulation via electrodes embedded in each forelimb and the contralateral hindlimb. Fifty units or about 10% of the total population were found in clusters of strictly somatosensory units which were activated by light tactile stimulation and with short latency from the contralateral body half. Some of these units had small receptive fields, but others showed convergence of information from large receptive fields which sometimes included parts of the ipsilateral body half. The different clusters appeared to constitute parts of a coherent structure which is located between 3-5 mm lateral to the midline at the anterior/posterior level of the trochlear nucleus, and with slanted dorsal-ventral distribution with the caudal parts above and the rostral parts below the Sylvian aqueduct. A somatotopical arrangement was found with the forelimb rostral to the hindlimb, and the suggested structure may be the somatosensory intercollicular nucleus which has been described by others.
D000161:Acoustic Stimulation; D000818:Animals; D002415:Cats; D004558:Electric Stimulation; D005260:Female; D005552:Forelimb; D006614:Hindlimb; D007245:Inferior Colliculi / Q000502:physiology*; D008297:Male; D008636:Mesencephalon / Q000502:physiology*; D010465:Perception / Q000502:physiology; D010775:Photic Stimulation; D013003:Somatosensory Cortex / Q000502:physiology*; D013477:Superior Colliculi / Q000502:physiology*