This proposal is concerned with the mechanisms responsible for the conversion of medial lemniscal input into thalamocortical relay cell output in the ventral posterolateral (VPL) nucleus of the cat thalamus. Such mechanisms form one of the fundamental bases for the perception by higher centers of the qualities of amplitude and velocity of a peripheral stimulus, qualities that are not coded for directly in the place and modality properties of VPL neurons, as customarily investigated but which become first affected in lesions of the central somatosensory systems.
The specific aims are: (i) to characterize the relay and gating functions of VPL neurons receiving inputs from different classes of cutaneous mechanoreceptors; (ii) to correlate differences in VPL relay neuron behavior under afferent driving with the numbers and distributions of lemniscal and GABA containing synapses; (iii) to determine the role of GABA in VPL relay cell function and the differential roles of intrinsic and reticular nucleus GABA neurons. Four primary sets of experiments are to be conducted: (a) a rigorous extra- and intracellular physiological study of cutaneous mechanoreceptor inputs to identified VPL relay neurons, using quantitatively controlled stimuli; (b) a quantitative electron microscopic study of the synaptic relations of physiologically characterized and intracellularly stained VPL cells and medial lemniscal axons; (c) an iontophoretic study of the effects of GABA, and bicuculline methiodide on VPL relay cell function; (d) a study of the effects of reversible blockade of the reticular nucleus by injections of cobalt ions on VPL relay cell function.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS022317-04
Application #
3404557
Study Section
Neurology B Subcommittee 1 (NEUB)
Project Start
1984-09-01
Project End
1992-08-31
Budget Start
1987-09-01
Budget End
1988-08-31
Support Year
4
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of California Irvine
Department
Type
Schools of Medicine
DUNS #
161202122
City
Irvine
State
CA
Country
United States
Zip Code
92697
Jones, E G (1998) Viewpoint: the core and matrix of thalamic organization. Neuroscience 85:331-45
Jones, E G (1998) A new view of specific and nonspecific thalamocortical connections. Adv Neurol 77:49-71;discussion 72-3
Liu, X B; Warren, R A; Jones, E G (1995) Synaptic distribution of afferents from reticular nucleus in ventroposterior nucleus of cat thalamus. J Comp Neurol 352:187-202
Liu, X B; Honda, C N; Jones, E G (1995) Distribution of four types of synapse on physiologically identified relay neurons in the ventral posterior thalamic nucleus of the cat. J Comp Neurol 352:69-91
Manger, P R; Woods, T M; Jones, E G (1995) Representation of the face and intraoral structures in area 3b of the squirrel monkey (Saimiri sciureus) somatosensory cortex, with special reference to the ipsilateral representation. J Comp Neurol 362:597-607
Rausell, E; Jones, E G (1995) Extent of intracortical arborization of thalamocortical axons as a determinant of representational plasticity in monkey somatic sensory cortex. J Neurosci 15:4270-88
Warren, R A; Agmon, A; Jones, E G (1994) Oscillatory synaptic interactions between ventroposterior and reticular neurons in mouse thalamus in vitro. J Neurophysiol 72:1993-2003
Warren, R A; Jones, E G (1994) Glutamate activation of cat thalamic reticular nucleus: effects on response properties of ventroposterior neurons. Exp Brain Res 100:215-26
Benson, D L; Gall, C M; Isackson, P J (1992) Dendritic localization of type II calcium calmodulin-dependent protein kinase mRNA in normal and reinnervated rat hippocampus. Neuroscience 46:851-7
Benson, D L; Isackson, P J; Gall, C M et al. (1992) Contrasting patterns in the localization of glutamic acid decarboxylase and Ca2+/calmodulin protein kinase gene expression in the rat central nervous system. Neuroscience 46:825-49

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