COMPUTATION STYLES IN IDENTIFIED NEURONS FROM THE CRAB STOMATOGASTRIC GANGLION.

D.K. Hartline*, K. Graubard, A.E. Wilensky and G. Orr

U. of Hawaii, Honolulu, HI 96822 and U. of Washington, Seattle, WA 98195

Poster

presented at the 26th annual meeting of the Society for Neuroscience in Washington D.C. November 17, 1996 (Abstr. 59.5) *.

SUMMARY Intermixture of input and output synapses along neurites, as occurs in stomatogastric neurons, opens a possibility for "local" integration of inputs in relative isolation from other functional regions of a cell. The rate of attenuation of electrical signals spreading from a synaptic input to more distant neurites is a key factor in this. VD and IC neurons present very different morphologies and may thus differ in their signal-attenuation and characteristics and potential for local and global computation. We compared signal attenuation in passive compartmental models of VD and IC to assess potential differences in computational capabilities. Serial optical sections of Lucifer yellow or Texas red-filled cells were made with a confocal microscope for 3D reconstruction with imaging software. For current injected in distal neurites of either cell type, attenuation of voltage responses was five-fold in secondary neurites and distal neurites "down stream" of them. In VD but not IC, attenuation was less in neurites having a secondary neurite in common with the injection site, and still less in those having a post-secondary neurite in common. The results suggest that local computation, while possible in both types, may be more regionally limited in IC than in VD cells