A comparison of three-dimensional swimming paths during visually-evoked versus auditory-evoked escape swims in larval zebrafish

Graduation Date

2016

Document Type

Thesis

Program

Other

Program

Thesis (M.A.)--Humboldt State University, Psychology: Academic Research, 2016

Committee Chair Name

Ethan Gahtan

Committee Chair Affiliation

HSU Faculty or Staff

Keywords

Escape response, Vertical swim, Zebrafish, Visual, Humboldt State University -- Theses -- Psychology, Behavior, Auditory

Abstract

Escape behaviors have been studied in zebrafish and aquatic organisms by neuroscientists seeking cellular-level descriptions of neural circuits, but few studies have examined vertical swimming during escapes. I analyzed three-dimensional swimming paths of larval zebrafish during visually-evoked and auditory-evoked escapes while the fish were in a cubical tank with equal vertical and lateral range. A vertical component was found in both visually-evoked and auditory-evoked escapes. The initial 10 seconds of stimulation involved an equal amount of increased vertical and horizontal movement for both escape behaviors, followed by a decrease in total distance traveled below that of spontaneous swimming. These escapes differentiated only after the initial 10 seconds of stimulation, with visually-evoked escapes involving a greater amount of vertical distance travelled and greater decrease in horizontal movement when compared to that of auditory-evoked escapes. To determine how these reflexes develop across ages at which zebrafish larvae are commonly used in behavioral assays, I tested light dimming-evoked and tap-evoked escapes in groups of larvae at 4 different ages: 6, 8, 10, and 12 days post fertilization. Both behaviors were found to not change as the age of the zebrafish increased. A comparison of light dimming-evoked diving in zebrafish to similar behaviors of other aquatic animals suggests it is a protean defense reflex against specific predation threats. These results also imply that future studies of the neural mechanisms of visual behavior in zebrafish should consider vertical movement control elements.

https://scholarworks.calstate.edu/concern/theses/dz010s59x

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