The vertical-horizontal neurone (VH) in the lobula plate of the blowfly,Phaenicia

Summary The anatomy and physiology of a motion-sensitive neurone, the vertical-horizontal (VH-) cell in the third visual neuropil (lobula plate) of the blowfly,Phaenicia was studied by intracellular recordings combined with dye injection. The cell possesses two dendritic fields in different layers of the lobula plate. The axon runs jointly with those of the vertical cells along the caudal surface of the lobula plate and terminates in the central protocerebrum lateral to the esophageal canal. The receptive field of the VH-cell is subdivided into two physiologically different parts which correspond to the two dendritic fields: if the input reaches the dendritic field residing in a more caudal layer (V-layer), the cell responds maximally to vertical pattern motion; whereas if the input reaches the dendritic field residing in a more rostral layer (H-layer), the cell responds maximally to horizontal pattern motion. The VH-neurone responds maximally to a contrast frequency of approximately / 1.8 Hz which coincides with the contrast frequency dependence of optomotor (following) responses. It is, therefore, considered to be a likely candidate mediating the pitch response (Blondeau and Heisenberg 1982) in flies.