title: To-and-fro optical voltage signal propagation between the insular gustatory and parietal oral somatosensory areas in rat cortex slices.
abstract: Taste perception depends not only on special taste information processed in the insular cortex, but also on oral somesthetic processing in the parietal cortex. Many insular cortex neurons show multimodal responsiveness. Such multimodality may be enabled by signal exchange between these two cortices. By using the protocol that we have developed, a synchronized population oscillation of synaptic potentials was induced in the parietal cortex by stimulation to the insular cortex in rat neocortex slices. The spatiotemporal pattern of propagation of this oscillation was studied by recording voltage-sensitive optical signals and field potentials. The first wavelet of the oscillation was propagated from the insular stimulation site to the parietal cortex. However, the second and later wavelets propagated back from the parietal cortex to the insular cortex. The oscillation was detected in the insular cortex as well, but was actually generated in the parietal cortex. Thus, the initial peak of optical signal, sent from the insular to parietal cortex, served to generate oscillatory responses in the parietal cortex, which propagated back to the insular cortex wave-by-wave. We propose that this to-and-fro propagation may be an artificially exaggerated demonstration of an intrinsic mechanism relevant to signal exchange between the parietal and insular cortices.
authors.affiliation: Department of Integrative Brain Science, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoshimura
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kato
authors.forename: Tokio
authors.initials: T
authors.lastname: Sugai
authors.forename: Makoto
authors.initials: M
authors.lastname: Honjo
authors.forename: Jun
authors.initials: J
authors.lastname: Sato
authors.forename: Natsuki
authors.initials: N
authors.lastname: Segami
authors.forename: Norihiko
authors.initials: N
authors.lastname: Onoda
mesh_terms: D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology*; D003344:Cortical Synchronization; D004558:Electric Stimulation; D004594:Electrophysiology; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects / Q000502:physiology*; D005456:Fluorescent Dyes; D009055:Mouth / Q000502:physiology; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology; D009924:Organ Culture Techniques; D010296:Parietal Lobe / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013649:Taste / Q000187:drug effects / Q000502:physiology*
chemical_list: D005456:Fluorescent Dyes; D002110:Caffeine