Dendritic Structure and Receptive-Field Organization of Optic Flow Processing Interneurons in the Fly

Abstract

Krapp, Holger G., Bärbel Hengstenberg, and Roland Hengstenberg. Dendritic structure and receptive-field organization of optic flow processing interneurons in the fly. J. Neurophysiol. 79: 1902–1917, 1998. The third visual neuropil (lobula plate) of the blowfly Calliphora erythrocephala is a center for processing motion information. It contains, among others, 10 individually identifiable “vertical system” (VS) neurons responding to visual wide-field motions of arbitrary patterns. We demonstrate that each VS neuron is tuned to sense a particular aspect of optic flow that is generated during self-motion. Thus the VS neurons in the fly supply visual information for the control of head orientation, body posture, and flight steering. To reveal the functional organization of the receptive fields of the 10 VS neurons, we determined with a new method the distributions of local motion sensitivities and local preferred directions at 52 positions in the fly's visual field. Each neuron was identified by intracellular staining with Lucifer yellow and three-dimensional reconstructions from 10-μm serial sections. Thereby the receptive-field organization of each recorded neuron could be correlated with the location and extent of its dendritic arborization in the retinotopically organized neuropil of the lobula plate. The response fields of the VS neurons, i.e., the distributions of local preferred directions and local motion sensitivities, are not uniform but resemble rotatory optic flow fields that would be induced by the fly during rotations around various horizontal axes. Theoretical considerations and quantitative analyses of the data, which will be presented in a subsequent paper, show that VS neurons are highly specialized neural filters for optic flow processing and thus for the visual sensation of self-motions in the fly.

Neural encoding of behaviourally relevant visual-motion information in the fly

“…This change in orientation is reflected by the change in local preferred directions of VS6 cells in corresponding regions of its receptive field. Experimental data from Refs [29,32]. presynaptic neuron, whereas both the presynaptic Ca 2+ concentration and the postsynaptic spike rate decrease only slightly below their resting levels.…”

“…The preferred directions of the small-field elements that synapse onto a given TC appear to coincide with the directions of the velocity vectors characterizing the optic flow induced during particular types of self-motion (Fig. 1a) [27, 29,30]. The sophisticated global patterns of preferred directions do not depend on visual experience and thus represent phylogenetic rather than developmental adaptations to optic-flow analysis [31].…”

“…Electrophysiological and optical recording data reproduced from Ref. [42], cell reconstructions shown in (a) reproduced from Refs [13,29].…”

Bio-inspired visual ego-rotation sensor for MAVs

“…b Connection strength matrix for network coupling. The axon terminal output of a cell is exited strongly by its own dendritic input, slightly less by its immediate neighbors, little by more distal cells and even inhibited by most distal cells analyzed here additionally includes the effect of the HSN cell on the dendritic compartment of VS 10, thereby accounting for reported responses to dorsal horizontal motion (Krapp et al 1998;Borst 2003, 2007).…”

“…There have been studies on basic motion detection circuits for rotation detection (O'Carroll et al 2006;Aubepart et al 2004), but despite considerable advances in understanding of the fly neuronal rotation sensing circuitry (Krapp et al 1998;Borst et al 2010;Cuntz et al 2007) there have been few biologically realistic practical applications involving these findings. O'Carroll et al (2006) have put forth a rotation sensor using a custom aVLSI chip that relies on basic motion detection circuitry for a one-dimensional circular array of 40 input photodiodes.…”