Variability of peripheral representation in ventrobasal thalamic nuclei of the cat: Effects of chloralose treatment

摘要: Abstract The effects of the intravenous administration α-chloralose on static and dynamic properties 20 highly specific somatosensory neurons isolated within forepaw focus thalamic ventralis posterolateralis (VPL) nucleus locally anesthetized cats were studied. Observations made (extracellular recording) before, during, after injection. Nine units sample identified as thalamocortical relay cells. Spontaneous activity, activity during tonic afferent drive maintained by weak peripheral stimuli, responsiveness to stimulation dorsal column dorsolateral funiculus, location extent receptive fields examined. In none did drug bring light aspecific such those previously described in sizable proportions cell populations sampled from VPL with chloralose or subjected surgical interventions which lower amount ascending corticofugal influx thalamus. After treatment, eight (six cells) exhibited continuous (in two cases) discontinuous enlargements their fields, which, however, remained rather small compared fields. are tentatively explained hypothesizing “unmasking” a convergent input, directed only fraction cells normally blocked inhibition. It is suggested that unmasked input could be mediated spinocervicothalamic pathway.