Quantification of Visual Fixation Behavior and Spatial Orientation Memory in Drosophila melanogaster.

Hung-Hsiu Yen,Chung-Chuan Lo,Rui Han

doi:10.3389/fnbeh.2019.00215

Hung-Hsiu Yen, Chung-Chuan Lo + Show 1 more

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https://doi.org/10.3389/fnbeh.2019.00215

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Abstract

Drosophila Melanogaster has been shown to exhibit short-term orientation memory by fixating on orientations toward previously displayed visual landmarks. However, the fixation behavior varies and is often mixed with other types of movement. Therefore, carefully designed statistical measures are required in order to properly describe the characteristics of the fixation behavior and to quantify the orientation memory exhibited by the fruit flies. To this end, we propose a set of analytical methods. First, we defined the deviation angle which is used to quantify the deviation of the fruit fly's heading from the landmark positions. The deviation angle is defined based on the fruit fly's perspective and is able to reveal more task-relevant movement patterns than the commonly used definition which is based on the “observer's perspective.” We further introduce a temporal deviation angle plot which visually presents the complex movement pattern as a function of time. Next, we define the fixation index which tolerates fluctuation in the movement and performs better in quantifying the level of fixation behavior, or the orientation memory, than the conventional method.

Highlights

Visual pattern fixation is an innate behavior of many insects and is characterized by persistent movement toward a visually salient landmark in the environment
In a Buridan-type of task, a central question is whether the fruit fly moves toward a visual landmark, or a specific orientation
We call such definition “observer’s perspective” because the dividing line is defined by the observer and walking on either side of the line does not make any difference to the fly, considering that the platform is symmetric along the line

Summary

Introduction

Visual pattern fixation is an innate behavior of many insects and is characterized by persistent movement toward a visually salient landmark in the environment. In Drosophila melanogaster, such behavior has been well-demonstrated by Buridan’s paradigm. Due to the innateness and robustness of visual pattern fixation, it has been used to test various cognitive functions such as visual and special working memory, and locomotive control (Powell and Dobzhansky, 1976; Götz, 1980; Goetz, 1989; Menzel et al, 1996; Strauss, 2002; Pan et al, 2009; Lin et al, 2013; Paulk et al, 2013). In the traditional Buridan’s Paradigm, a drum like arena is surrounded by fluorescent light tubes that illuminate the wall of the arena. The fly’s position is recorded and converted into deviation angles toward each of two landmarks (Strauss and Pichler, 1998; Colomb et al, 2012)

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