FUNCTIONAL-ORGANIZATION OF A NEURAL MAP IN THE CRICKET CERCAL SENSORY-SYSTEM

Citation
Ga. Jacobs et Fe. Theunissen, FUNCTIONAL-ORGANIZATION OF A NEURAL MAP IN THE CRICKET CERCAL SENSORY-SYSTEM, The Journal of neuroscience, 16(2), 1996, pp. 769-784
Citations number
47
Categorie Soggetti
Neurosciences,Neurosciences
Journal title
ISSN journal
02706474
Volume
16
Issue
2
Year of publication
1996
Pages
769 - 784
Database
ISI
SICI code
0270-6474(1996)16:2<769:FOANMI>2.0.ZU;2-X
Abstract
Directionally selective mechanosensory afferents in the cricket cereal sensory system form a map of air current direction in the terminal ab dominal ganglion. The global organization of this map was revealed by studying the anatomical relationships between an ensemble of sensory a fferents that represented the entire range of receptor hair directiona l sensitivities on the sensory epithelium. The shapes and three-dimens ional positions of the terminal arborizations of these cells were high ly conserved across animals. Afferents with similar directional sensit ivities arborized near each other within the map, and their terminal a rborizations showed significant anatomical overlap. There was a clear global organization pattern of afferents within the map: they were org anized into a spiral shape, with stimulus direction mapped continuousl y around the spiral. These results demonstrate that this map is not fo rmed via a direct point-to-point topographic projection from the senso ry epithelium to the CNS. Rather, the continuous representation of air current direction is synthesized within the CNS via an anatomical reo rganization of the afferent terminal arbors. The arbors are reorganize d according to a functional property that is independent of the locati on of the mechanoreceptor in the epithelium. The ensemble data were us ed to derive predictions of the patterns of steady-state excitation th roughout the map for different directional stimuli. These images repre sent quantitative and testable predictions of functional characteristi cs of the entire neural map.