Neuronal processing of translational optic flow in the visual system of the shore crab Carcinus maenas

Horseman, B.G., Macauley, M.W.S. and Barnes, W.J.P. (2011) Neuronal processing of translational optic flow in the visual system of the shore crab Carcinus maenas. Journal of Experimental Biology, 214(9), pp. 1586-1598. (doi:10.1242/jeb.050955)

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Publisher's URL: http://dx.doi.org/10.1242/jeb.050955

Abstract

This paper describes a search for neurones sensitive to optic flow in the visual system of the shore crab Carcinus maenas using a procedure developed from that of Krapp and Hengstenberg. This involved determining local motion sensitivity and its directional selectivity at many points within the neurone's receptive field and plotting the results on a map. Our results showed that local preferred directions of motion are independent of velocity, stimulus shape and type of motion (circular or linear). Global response maps thus clearly represent real properties of the neurones' receptive fields. Using this method, we have discovered two families of interneurones sensitive to translational optic flow. The first family has its terminal arborisations in the lobula of the optic lobe, the second family in the medulla. The response maps of the lobula neurones (which appear to be monostratified lobular giant neurones) show a clear focus of expansion centred on or just above the horizon, but at significantly different azimuth angles. Response maps such as these, consisting of patterns of movement vectors radiating from a pole, would be expected of neurones responding to self-motion in a particular direction. They would be stimulated when the crab moves towards the pole of the neurone's receptive field. The response maps of the medulla neurones show a focus of contraction, approximately centred on the horizon, but at significantly different azimuth angles. Such neurones would be stimulated when the crab walked away from the pole of the neurone's receptive field. We hypothesise that both the lobula and the medulla interneurones are representatives of arrays of cells, each of which would be optimally activated by self-motion in a different direction. The lobula neurones would be stimulated by the approaching scene and the medulla neurones by the receding scene. Neurones tuned to translational optic flow provide information on the three-dimensional layout of the environment and are thought to play a role in the judgment of heading.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Macauley, Dr Martin and Barnes, Dr W.Jon.P
Authors: Horseman, B.G., Macauley, M.W.S., and Barnes, W.J.P.
Subjects:Q Science > QH Natural history
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Journal of Experimental Biology
Publisher:Company of Biologists
ISSN:0022-0949
Copyright Holders:Copyright © 2011 Company of Biologists
First Published:First published in Journal of Experimental Biology 214(9):1586-1598
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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