2001 Fiscal Year Final Research Report Summary
Spatiotemporal propagation of excitation in the rat gustatory cortex
| Project/Area Number |
11671860
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Functional basic dentistry
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| Research Institution | Aichi-Gakuin University |
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Principal Investigator |
YOKOTA Tatsuko Aichi-Gakuin Univ., Sch. of Dent. Med, Research Assistant, 歯学部, 助手 (70192416)
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| Co-Investigator(Kenkyū-buntansha) |
SHIROZU Takamasa Aichi-Gakuin Univ., Sch. of Dent. Med, Research Assistant, 歯学部, 助手 (80308791)
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| Project Period (FY) |
1999 – 2001
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| Keywords | taste / gustatory cortex / optical imaging / voltage sensitive dye / electrical taste / field potential / rat |
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| Research Abstract |
The spatiotemporal pattern of neural activity in the gustatory cortex was examined by using the optical imaging technique with a voltage-sensitive dye (di-2-ANEPEQ) in anesthetized rats. Anodal electrical currents applied on the tongue evoked optical signals and field potentials in the gustatory cortex with similar peak latencies, 15〜45ms and 17〜37ms, respectively. The optical signals were evoked consistently over the cortical region where taste neurons had been identified electrophysiologically. These optical signals evoked by anodal currents probably resulted from activation of taste receptors, a phenomenon called "electrical taste". Peak latencies (8〜10ms) of optical signals evoked by cathodal currents were shorter than those evoked by anodal currents. These short latencies suggest that the cathodal currents activated directly nerve fibers including mechanosensitive and taste afferents.
Optical signals elicited by anodal currents under application of taste solution (0.2M NaCl(N), 0.03M HCl(H), 0.15M NaCl(S) and mixture of N and H (N+H)) on the tongue appeared on the same cortical region in spite of taste quality. This result suggests that N-, H- and NH-best neurons exist in the same cortical region. The optical signals under application of N or N+H spread over larger cortical region than those under application of H or S. In previous electrophysiological studies, the most frequent encounters with N-best neurons support the larger spread of optical signals under application of N or the mixture.
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