The overall goal of this research is to understand the role that trigeminal primary afferents play in coordinating movements involving the jaw, lip, tongue, pharynx and larynx. Many of the muscles of these structures lack classical proprioceptors, and it is hypothesized that mesencephalic primary afferent neurons provide sensory feedback for multiple structures. Four hypotheses are proposed: 1. Trigeminal proprioceptive afferents make monosynaptic connections onto hypoglossal and nucleus ambiguus motoneurons. 2. Trigeminal proprioceptive afferents integrate and coordinate activity of XII and AMB motoneurons via brainstem premotor neurons. This hypothesis will be tested by using intracellular recording in vivo to identify mono- and bisynaptic neural circuits between proprioceptive afferents and XII and AMB motoneurons and premotor neurons. The neurons will be identified, intracellularly stained, and connections of the stained neurons will be determined with the aid of additional neuroanatomical tracing techniques. 3. Trigeminal proprioceptive afferents participate in the inter-nuclear coordination of XII and trigeminal motoneurons through intrinsic interneurons. 4. Feedback and feedforward modulation between premotor and XII interneurons is conveyed via trigeminal proprioceptive afferents.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC004096-06
Application #
6634498
Study Section
Special Emphasis Panel (ZRG1-IFCN-5 (01))
Program Officer
Shekim, Lana O
Project Start
1999-04-01
Project End
2004-06-30
Budget Start
2003-04-01
Budget End
2004-06-30
Support Year
6
Fiscal Year
2003
Total Cost
$173,924
Indirect Cost
Name
University of Vermont & St Agric College
Department
Pathology
Type
Schools of Medicine
DUNS #
066811191
City
Burlington
State
VT
Country
United States
Zip Code
05405
Zhang, Jingdong; Luo, Pifu; Ro, Jin Y et al. (2012) Jaw muscle spindle afferents coordinate multiple orofacial motoneurons via common premotor neurons in rats: an electrophysiological and anatomical study. Brain Res 1489:37-47
Luo, Pifu; Zhang, Jingdong; Yang, Regina et al. (2006) Neuronal circuitry and synaptic organization of trigeminal proprioceptive afferents mediating tongue movement and jaw-tongue coordination via hypoglossal premotor neurons. Eur J Neurosci 23:3269-83
Zhang, J; Yang, R; Pendlebery, W et al. (2005) Monosynaptic circuitry of trigeminal proprioceptive afferents coordinating jaw movement with visceral and laryngeal activities in rats. Neuroscience 135:497-505
Zhang, Jingdong; Pendlebury, William W; Luo, Pifu (2003) Synaptic organization of monosynaptic connections from mesencephalic trigeminal nucleus neurons to hypoglossal motoneurons in the rat. Synapse 49:157-69
Zhang, Jingdong; Luo, Pifu (2003) Ultrastructural features of synapse from dorsal parvocellular reticular formation neurons to hypoglossal motoneurons of the rat. Brain Res 963:262-73
Zhang, Jingdong; Luo, Pifu (2002) Orexin B immunoreactive fibers and terminals innervate the sensory and motor neurons of jaw-elevator muscles in the rat. Synapse 44:106-10
Luo, P; Haines, A; Dessem, D (2001) Elucidation of neuronal circuitry: protocol(s) combining intracellular labeling, neuroanatomical tracing and immunocytochemical methodologies. Brain Res Brain Res Protoc 7:222-34
Zhang, J; Luo, P; Pendlebury, W W (2001) Light and electron microscopic observations of a direct projection from mesencephalic trigeminal nucleus neurons to hypoglossal motoneurons in the rat. Brain Res 917:67-80
Luo, P; Dessem, D; Zhang, J (2001) Axonal projections and synapses from the supratrigeminal region to hypoglossal motoneurons in the rat. Brain Res 890:314-29