THE LOCUST DCMD, A MOVEMENT-DETECTING NEURON TIGHTLY TUNED TO COLLISION TRAJECTORIES

Authors
Citation
Sj. Judge et Fc. Rind, THE LOCUST DCMD, A MOVEMENT-DETECTING NEURON TIGHTLY TUNED TO COLLISION TRAJECTORIES, Journal of Experimental Biology, 200(16), 1997, pp. 2209-2216
Citations number
32
Categorie Soggetti
Biology
ISSN journal
00220949
Volume
200
Issue
16
Year of publication
1997
Pages
2209 - 2216
Database
ISI
SICI code
0022-0949(1997)200:16<2209:TLDAMN>2.0.ZU;2-M
Abstract
A Silicon Graphics computer was used to challenge the locust descendin g contralateral movement detector (DCMD) neurone with images of approa ching objects. The DCMD gave its strongest response, measured as eithe r total spike number or spike frequency, to objects approaching on a d irect collision course. Deviation in either a horizontal or vertical d irection from a direct collision course resulted in a reduced response , The decline in the DCMD response with increasing deviation from a co llision course was used as a measure of the tightness of DCMD tuning f or collision trajectories. Tuning was defined as the half-width of the response when it had fallen to half its maximum level. The response t uning, measured as averaged mean spike number versus deviation away fr om a collision course, had a halfwidth at half-maximum response of 2.4 degrees-3.0 degrees for a deviation in the horizontal direction and 3 .0 degrees for a deviation in the vertical direction. Mean peak spike frequency showed an even sharper tuning, with a halfwidth at half-maxi mum response of 1.8 degrees for deviations away from a collision cours e in the horizontal plane.