(full paper is archived in the Miller Library)
Title: Development of the optic tectum in larval zebrafish
Student Author(s): Song, Bonita
Faculty Advisor(s): Thompson, Stuart
Location: Final Papers Biology 176H
Date: June 2004
Abstract: Zebrafish (Danio rerio) begin reacting to visual stimuli barely after hatching; by seven days, their saccade reflex (quickly flicking the head and eyes towards a stimulus) is fully developed. Therefore, the brain region responsible for these activities the optic tectum must undergo enormous transformation within this time period. In order to observe the morphology of this transformation, I examined 3-day old, 5-day old, and 7-day old larvae, accessing a variety of techniques. Specifically, I looked at: stained serial sections of whole fish using a conventional light microscope; confocal images of whole and dissected fish after injection with lipophilic FM 1-43FX dye; and scanning electron microscope images of FM 1-43FX-injected fish, which were produced on a recently-invented, serial-sectioning scanning electron microscope. Qualitative analysis reveals that structural change in the tectum is subtle but apparent, with cells proliferating most rapidly along the bilateral axis of the tectal lobes, and along the outermost tips of the distal ventricular branches.