title: Age-dependent emergence of a parieto-insular corticocortical signal flow in developing rats.
abstract: By using the procedure that we developed for inducing population oscillation, it was previously demonstrated that insular cortex stimulation can evoke insulo-parietal field potential propagation and synchronized population oscillation in the parietal cortex in slices obtained from mature rats (27-35 days old). By using the same procedure, we have now studied the reciprocal parieto-insular projection. Parietal cortex stimulation elicited synchronized population oscillation in the parietal--but not insular--cortex in mature tissues. In the insular cortex, the initial wavelet of the oscillation generated by parietal cortex stimulation propagated, but the entire oscillation did not. A prior induction--but not simultaneous occurrence--of oscillation in the parietal cortex sufficed to have this initial wavelet propagate. In immature tissue (9-10 days old), both the parietal cortex oscillation and the parieto-insular propagation were induced only with low [Mg2+]o. This age dependence is exactly the same as we previously observed for the reciprocal insulo-parietal propagation. Given that the parietal cortex receives somatosensory inputs from the oral cavity and the insular cortex receives primarily chemosensory inputs from the same source, the age-dependent changes in the availability of bidirectional signal traffic between these cortices might contribute to the development of multimodal responsiveness of taste neurons.
authors.affiliation: Department of Integrative Brain Science, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan. hyoshimu@kanazawa-med.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoshimura
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kato
authors.forename: Makoto
authors.initials: M
authors.lastname: Honjo
authors.forename: Tokio
authors.initials: T
authors.lastname: Sugai
authors.forename: Natsuki
authors.initials: N
authors.lastname: Segami
authors.forename: Norihiko
authors.initials: N
authors.lastname: Onoda
mesh_terms: D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000375:Aging / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D002110:Caffeine / Q000494:pharmacology; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000254:growth & development* / Q000528:radiation effects; D004347:Drug Interactions; D004558:Electric Stimulation / Q000379:methods; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005071:Evoked Potentials / Q000528:radiation effects; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D009434:Neural Pathways / Q000187:drug effects / Q000528:radiation effects; D009474:Neurons / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D010296:Parietal Lobe / Q000166:cytology / Q000187:drug effects / Q000254:growth & development* / Q000528:radiation effects; D051381:Rats; D017208:Rats, Wistar; D012236:Rhodanine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D019284:Thapsigargin / Q000494:pharmacology; D053778:Thiazolidines
chemical_list: D000697:Central Nervous System Stimulants; D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; D053778:Thiazolidines; D002110:Caffeine; D019284:Thapsigargin; D015763:2-Amino-5-phosphonovalerate; C029653:NK 2761; D012236:Rhodanine