Identification of visual pallial telencephalon in the goldfish, Carassius auratus: a combined cytochrome oxidase and electrophysiological study

A strategy based upon a comparative decrease. in bilateral symmetry of cyto chrome oxidase (COX) histochemistry following unilateral eye enucleation wa s used to identify the primary visual area in the area dorsalis of the tele ncephalon of the goldfish, Carassius auratus. The lateral zone of area dors alis (DI) at about the level of the anterior commissure exhibits such a bil ateral difference. A parallel decline in the symmetry COX reactivity was ob served in the associated part of the central zone (Dc). Electrophysiologica l activity using extracellular techniques confirmed the visually-driven act ivity of neurons in these areas. Lesions confirmed the loci in the lateral zone of area dorsalis, including both its dorsal and ventral parts. Single- and multi-unit recordings exhibited a variety of responses to different li ght stimuli. Single unit latency measures proved not to be a reliable measu re of target areas. Responses habituated to stimuli repeated within 5 s and were only reliably evoked with intervals greater than several seconds. (C) 2001 Elsevier Science BY. All rights reserved.