Figure 6.

Visual system of the blowfly and neural circuits extracting optic flow information from the retinal image sequences. (A) Schematic of a horizontal section of the fly's brain projected onto a photograph of its head, with the retina and the three main visual neuropiles labeled. (B) Wiring sketch of some LWCs sensitive to different types of horizontal motion in the lobula plate of the blowfly. The HSE cells, one type of HS cells, which respond best to coherent wide-field motion, and the FD1 cells, a special type of FD cells, which are most sensitive to the motion of objects, are highlighted. (C) Structure of an FD1 cell with its dendritic tree residing in the lobula plate. The cell is shown in a whole-mount preparation after it has been injected with the fluorescent dye Lucifer Yellow. (D) Dependence of the normalized response amplitude of an HSE and a FD1 cell on the angular horizontal extent of a moving pattern. The responses are based on computer simulations of a circuit model [as shown in (B)]; the model responses mimic the physiologically determined responses (Data from Hennig and Egelhaaf, 2012).