Related Experiment Video
Updated: Aug 25, 2026

Eye Removal in Living Zebrafish Larvae to Examine Innervation-dependent Growth and Development of the Visual System
Published on: February 11, 2022
A pallial visual area in the telencephalon of the bony fish Polypterus
R Glenn Northcutt1, Wolfgang Plassmann, Preston H Holmes
1Neurobiology Unit, Scripps Institution of Oceanography, and Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093-0201, USA. rgnorthcutt@ucsd.edu
Abstract:
The dorsal (P2) and lateral (P3) pallial zones of bichirs receive a substantial projection from nucleus medianus of the posterior tuberculum. Although nucleus medianus does not receive a direct retinal input, its close proximity to ascending tectal efferents suggests that it might receive a tectal input and form a segment of a retinotectal-tubercular pathway to the pallium. In order to test this possibility, evoked responses to light flashes were electrophysiologically recorded and tectal efferents were experimentally determined in bichirs. These experiments suggest that a single visual field exists across the dorsal and lateral pallial zones and that this field is mediated by nucleus medianus, which does receive a direct tectal projection. This visual pathway appears to be uniquely derived and not homologous to any other known pathway in tetrapods. Furthermore, these results support the contention that the P2 and P3 pallial zones in bichirs are subdivisions of a single pallial zone.
Related Concept Videos
Association Areas of the Cortex
Prefrontal Association Area: This area is located in the frontal lobe and is involved in planning, decision-making, and moderating social behavior. It connects with primary motor areas,...
Vision
Anatomy of the Eyeball
Visual System
Once through the pupil, the light passes through the lens, a...
Diencephalon: Anatomical Regions

