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new computer simulations of macular neural functioningWe use high performance graphics workstations and supercomputers to study the functional significance of the three-dimensional (3-D) organization of gravity sensors. These sensors have a prototypic architecture foreshadowing more complex systems. Scaled-down simulations run on a Silicon Graphics workstation and scaled-up, 3-D versions run on a Cray Y-MP supercomputer. A semi-automated method of reconstruction of neural tissue from serial sections studied in a transmission electron microscope has been developed to eliminate tedious conventional photography. The reconstructions use a mesh as a step in generating a neural surface for visualization. Two meshes are required to model calyx surfaces. The meshes are connected and the resulting prisms represent the cytoplasm and the bounding membranes. A finite volume analysis method is employed to simulate voltage changes along the calyx in response to synapse activation on the calyx or on calyceal processes. The finite volume method insures that charge is conserved at the calyx-process junction. These and other models indicate that efferent processes act as voltage followers, and that the morphology of some afferent processes affects their functioning. In a final application, morphological information is symbolically represented in three dimensions in a computer. The possible functioning of the connectivities is tested using mathematical interpretations of physiological parameters taken from the literature. Symbolic, 3-D simulations are in progress to probe the functional significance of the connectivities. This research is expected to advance computer-based studies of macular functioning and of synaptic plasticity.
Document ID
20020016018
Document Type
Conference Paper
Authors
Ross, Muriel D.
(NASA Ames Research Center Moffett Field, CA United States)
Doshay, D.
(Sterling Software, Inc. Palo Alto, CA United States)
Linton, S.
(Sterling Software, Inc. Palo Alto, CA United States)
Parnas, B.
(National Academy of Sciences - National Research Council Moffett Field, CA United States)
Montgomery, K.
(Sterling Software, Inc. Palo Alto, CA United States)
Chimento, T.
(Sterling Software, Inc. Palo Alto, CA United States)
Date Acquired
August 20, 2013
Publication Date
June 8, 1994
Subject Category
Aerospace Medicine
Meeting Information
18th Barany Society Meeting(Uppsala)
Funding Number(s)
CONTRACT_GRANT: NIH-5-RO1-MH47305-03
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.