Receptive field properties of thalamo-cortical taste relay neurons in the parvicellular part of the posteromedial ventral nucleus in rats.
Twenty-five taste and 35 mechanoreceptive neurons were recorded from the parvicellular part of the posteromedial ventral nucleus (VPMpc) in rats. Among them, 14 (56%) of the taste and 7 (18.4%) of the mechanoreceptive neurons were antidromically activated from the cortical taste area (CTA) with a latency of 1-4 ms and identified as thalamocortical (TC) relay neurons. No significant differences were evident in the receptive field properties or in the location in the VPMpc between the TC and non-TC neuron groups. Two classes of TC neurons were recognized: one class consisted of neurons which were most excited by NaCl among the four basic taste stimuli with receptive fields (RFs) confined to a part of the oral cavity, e.g. the anterior tongue, and the other class contained neurons which were most excited by sucrose or HCl, with RFs over a wide area of the oral cavity. Both the TC and non-TC neurons showed similar effects of CTA stimulation: post-stimulus time histograms revealed a long lasting inhibition followed by a rebound facilitation of spontaneous discharge.
Ogawa
H
H
Department of Physiology, Kumamoto University Medical School, Japan.
Nomura
T
T
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002540:Cerebral Cortex / Q000502:physiology*; D005260:Female; D008465:Mechanoreceptors / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013649:Taste / Q000502:physiology*; D013787:Thalamic Nuclei / Q000502:physiology*