2006 Fiscal Year Final Research Report Summary
Somatosensory processing of mastication-induced sensory inputs in the cerebral cortex
| Project/Area Number |
17591933
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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 | Niigata University |
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Principal Investigator |
YAMAMURA Kensuke Niigata University, Institute of Medicine and Dentistry, Div.Oral, Associate Professor, 医歯学系, 助教授 (90272822)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Makoto Niigata University, Institute of Medicine and Dentistry, Associate Professor, 医歯学系, 助教授 (00303131)
YAMADA Yoshiaki Niigata University, Institute of Medicine and Dentistry, Professor, 医歯学系, 教授 (80115089)
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| Project Period (FY) |
2005 – 2006
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| Keywords | neuroscience / mastication / cerebral cortex / somatosensory integration / sensory cognition / primary somatosensory cortex / orofacial sensation |
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| Research Abstract |
Sensory information, arising from orofacial mechanoreceptor discharge associated with masticatory movements, has an important role in controlling masticatory movements reflexly. It is also important in detecting position and/or consistency of ingested food. In the present study effects of mastication on non-nociceptive orofacial sensory transmission of the somatosensory pathways were tested. To achieve this, single-unit activities of the face primary somatosensory cortex (face-SI) neurons responding to low-intensity electrical stimulation of the inferior alveolar nerve (IAN) were recorded during mastication in awake rabbits. The entire masticatory sequence was divided into the preparatory period (PP), the rhythmic-chewing period (RC) and the preswallow period (PS). A total of 112 face-SI neurons were tested for the effects of mastication. The responsiveness of most neurons and the JOR were modulated during different periods of mastication. The IAN-evoked activity was attenuated in a majority of the neurons during at least one of the masticatory periods. A considerable number of face-SI neurons showed mastication-related activity although their responsiveness to IAN stimulation was strongly suppressed (i.e. almost "gated out") during mastication. It was notable that mastication-related activity still remained even after the blockage of peripheral sensory inputs in 60% of such neurons. The findings indicate that 1)sensory transmissions of the somatosensory pathways may be modulated during mastication, and that 2)activity of face-SI neurons during mastication may not necessarily be a simple reflection of movement-induced stimulation of orofacial mechanoreceptors, and suggest that somatosensory integration of a texture of food occur within face SI
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