1987 Fiscal Year Final Research Report Summary
Central mechanisms controlling oral activities during ingestive behavior
| Project/Area Number |
61570882
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional basic dentistry
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| Research Institution | Osaka University |
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Principal Investigator |
YAMAMOTO Takashi Faculty of Dentistry, Osaka University, 歯学部, 助教授 (60028793)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Taste / Cerebral cortex / Neural acitvity / Chronic recording / Feeding behavior / 摂食行動 / 飲水行動 |
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| Research Abstract |
Unit activities of neurons in the cortical tongue sensory area and the lateral hypothalamus (LH) were recorded with chronically implanted platinum-iridium fine wires during natural ingestive behavior of Wistar male rats. Implantation of the fine wires and other necessary surgical operations were performed under deep anesthesia with sodium pentobarbital (50 mg/kg) and urethane (750 mg/kg).
1. Cortical neurons were classified into the following 7 types according to their response properties: 1) Phasic tactile neurons, which showed rhythmic phasic activities at different phases of the licking cycle during licking of liguids. 2) Movement-related neurons which increased or decreased their activities during licking, chewing, or grooming without correlations with any cycleof jaw or tongue movements. 3) Temperature neurons which changed their spontaneous firing rates to licking of cold and/or warm water. 4) Neurons that seemed to be related to anticipation of ingestion. 5) Attention neurons whi
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ch responded vigorously by startle stimuli. 6) Taste neurons which increased or decreased their discharge rates during licking of particular taste solutions. 7) Taste-hedonic neurons which showed differential response patterns depending on the palatability of taste solutions. These results show that neurons in the cortical tongue sensory area possess different response characteristics corresponding to each aspect of ingestive behavior. Some of these functionally differrent neurons were organized anatomically separately within the cortex. Cortical neurons with these modality-specific and behavior-dependent responsivities, togehter with their spatial arrangement in the cortex may serve for perception of taste, integration of orolingual sensory inputs, and control of ingestive behavior.
2. About half of the LH neurons histologically identified changed their spontaneous rates after onset of cue tone (4.5 KHz) presented 5-10 sec before the start of licking. The change of activity seemed to reflect emotional (anticipatory) behavior and searching behavior including movement-related reaction and sniffing. LH neurons were classified into the 3 types according to their response properties during licking period: 1) Taste neurons (5%), 2) Taste-hedonic neurons (35%), 3) Neurons (60%), which showed no or non-specific responses during licking behavior regardless the taste qualities. These results suggest that LH neurons are responsible for arousal state expecting rewards, and licking behavior namely based on the hedonics of the rewards. Less
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Research Products
(11 results)
