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Open-field arena boundary is a primary object of exploration for Drosophila.

Soibam B, Mann M, Liu L, Tran J, Lobaina M, Kang YY, Gunaratne GH, Pletcher S, Roman G - Brain Behav (2012)

Bottom Line: These experiments support the conclusion that the wall-following behavior of Drosophila is best characterized by a preference for the arena boundary, and not thigmotaxis or centrophobicity.Since the boundary preference could derive from highly linear trajectories, we further developed a simulation program to model the effects of turn angle on the boundary preference.Hence, low turn angled movement does not drive the boundary preference.

View Article: PubMed Central - PubMed

ABSTRACT
Drosophila adults, when placed into a novel open-field arena, initially exhibit an elevated level of activity followed by a reduced stable level of spontaneous activity and spend a majority of time near the arena edge, executing motions along the walls. In order to determine the environmental features that are responsible for the initial high activity and wall-following behavior exhibited during exploration, we examined wild-type and visually impaired mutants in arenas with different vertical surfaces. These experiments support the conclusion that the wall-following behavior of Drosophila is best characterized by a preference for the arena boundary, and not thigmotaxis or centrophobicity. In circular arenas, Drosophila mostly move in trajectories with low turn angles. Since the boundary preference could derive from highly linear trajectories, we further developed a simulation program to model the effects of turn angle on the boundary preference. In an hourglass-shaped arena with convex-angled walls that forced a straight versus wall-following choice, the simulation with constrained turn angles predicted general movement across a central gap, whereas Drosophila tend to follow the wall. Hence, low turn angled movement does not drive the boundary preference. Lastly, visually impaired Drosophila demonstrate a defect in attenuation of the elevated initial activity. Interestingly, the visually impaired w(1118) activity decay defect can be rescued by increasing the contrast of the arena's edge, suggesting that the activity decay relies on visual detection of the boundary. The arena boundary is, therefore, a primary object of exploration for Drosophila.

No MeSH data available.


Related in: MedlinePlus

A time-dependent preference for a recessed alcove with opaque walls. (A). Diagram of the arena used in this experiment. Four different arena permutations were tested in which the walls of the arena (circular part) and the alcove were either clear or opaque. (B). The mean time spent in the alcove per minute is shown for each of the four arena permutations. No significant differences were found for the two arenas with opaque circles. Flies spent significantly more time in the alcove in the experiment with the clear circle and dark alcove than in the other three arenas (Bonferroni–Dunn; P < 0.001 for all comparisons). There was also a significant effect of time. n = 32 for each arena. Cove = 11.5% of perimeter, cove neutrality = 6.9 sec/min.
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fig03: A time-dependent preference for a recessed alcove with opaque walls. (A). Diagram of the arena used in this experiment. Four different arena permutations were tested in which the walls of the arena (circular part) and the alcove were either clear or opaque. (B). The mean time spent in the alcove per minute is shown for each of the four arena permutations. No significant differences were found for the two arenas with opaque circles. Flies spent significantly more time in the alcove in the experiment with the clear circle and dark alcove than in the other three arenas (Bonferroni–Dunn; P < 0.001 for all comparisons). There was also a significant effect of time. n = 32 for each arena. Cove = 11.5% of perimeter, cove neutrality = 6.9 sec/min.

Mentions: The basis for the Drosophila corner preference was examined further using a circular arena with a radius of 4.2 cm and a 2.56 cm2 recessed alcove (Fig. 3A). This alcove provided the fly an area further distanced from the arena center, as well as two external 90° corners as additional thigmotactic substrates. This alcove accounts for ∼11.5% of the arena perimeter. If the flies responded neutrally to the cove compared to the rest of the boundary, they would be present within this area approximately 6.9 sec/min. Since there appeared to be a significant effect of wall opacity in driving the fly's behavior in the previous experiment (Fig. 2), we examined the alcove arena with four sequential experiments, altering the vertical surface that was opaque (Fig. 3). Even when the circular edge of the alcove arena is clear, the flies demonstrate a significant preference for the alcove; an even stronger preference for the alcove is seen when the alcove walls are opaque and the circular edge is clear (Fig. 3B). When the circular edge of the arena was darkened, wild-type flies demonstrated little preference for the alcove and the external corners contained therein (Fig. 3B). Similar to the results with the darkened internal corners, there was a significant interaction between time in the arena and the preference for the darkened alcove (Fig. 3B; F9, 1240 = 7.122, P-value < 0.0001). This alcove preference increases as specific exploration of the novel arena decreases. In all four experiments with this cove arena, the flies spend significantly more time at the arena's boundary than in the central zone (data not shown). Since the alcove preference is not expressed during the first minute within the arena, while the flies are still expressing significant wall-following behavior, and the alcove represents the furthest distance from the center, centrophobicity does not account for the dominant wall-following behavior. We also failed to find a difference between the time attending a 1.5 cm black wall arc and an identically sized area at the opposite end of an 8.4 cm circular arena (t = –1.55, P-value = 0.13, df = 31) suggesting that neither the black wall nor the contrast of a black-clear border was preferentially attended.


Open-field arena boundary is a primary object of exploration for Drosophila.

Soibam B, Mann M, Liu L, Tran J, Lobaina M, Kang YY, Gunaratne GH, Pletcher S, Roman G - Brain Behav (2012)

A time-dependent preference for a recessed alcove with opaque walls. (A). Diagram of the arena used in this experiment. Four different arena permutations were tested in which the walls of the arena (circular part) and the alcove were either clear or opaque. (B). The mean time spent in the alcove per minute is shown for each of the four arena permutations. No significant differences were found for the two arenas with opaque circles. Flies spent significantly more time in the alcove in the experiment with the clear circle and dark alcove than in the other three arenas (Bonferroni–Dunn; P < 0.001 for all comparisons). There was also a significant effect of time. n = 32 for each arena. Cove = 11.5% of perimeter, cove neutrality = 6.9 sec/min.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3345355&req=5

fig03: A time-dependent preference for a recessed alcove with opaque walls. (A). Diagram of the arena used in this experiment. Four different arena permutations were tested in which the walls of the arena (circular part) and the alcove were either clear or opaque. (B). The mean time spent in the alcove per minute is shown for each of the four arena permutations. No significant differences were found for the two arenas with opaque circles. Flies spent significantly more time in the alcove in the experiment with the clear circle and dark alcove than in the other three arenas (Bonferroni–Dunn; P < 0.001 for all comparisons). There was also a significant effect of time. n = 32 for each arena. Cove = 11.5% of perimeter, cove neutrality = 6.9 sec/min.
Mentions: The basis for the Drosophila corner preference was examined further using a circular arena with a radius of 4.2 cm and a 2.56 cm2 recessed alcove (Fig. 3A). This alcove provided the fly an area further distanced from the arena center, as well as two external 90° corners as additional thigmotactic substrates. This alcove accounts for ∼11.5% of the arena perimeter. If the flies responded neutrally to the cove compared to the rest of the boundary, they would be present within this area approximately 6.9 sec/min. Since there appeared to be a significant effect of wall opacity in driving the fly's behavior in the previous experiment (Fig. 2), we examined the alcove arena with four sequential experiments, altering the vertical surface that was opaque (Fig. 3). Even when the circular edge of the alcove arena is clear, the flies demonstrate a significant preference for the alcove; an even stronger preference for the alcove is seen when the alcove walls are opaque and the circular edge is clear (Fig. 3B). When the circular edge of the arena was darkened, wild-type flies demonstrated little preference for the alcove and the external corners contained therein (Fig. 3B). Similar to the results with the darkened internal corners, there was a significant interaction between time in the arena and the preference for the darkened alcove (Fig. 3B; F9, 1240 = 7.122, P-value < 0.0001). This alcove preference increases as specific exploration of the novel arena decreases. In all four experiments with this cove arena, the flies spend significantly more time at the arena's boundary than in the central zone (data not shown). Since the alcove preference is not expressed during the first minute within the arena, while the flies are still expressing significant wall-following behavior, and the alcove represents the furthest distance from the center, centrophobicity does not account for the dominant wall-following behavior. We also failed to find a difference between the time attending a 1.5 cm black wall arc and an identically sized area at the opposite end of an 8.4 cm circular arena (t = –1.55, P-value = 0.13, df = 31) suggesting that neither the black wall nor the contrast of a black-clear border was preferentially attended.

Bottom Line: These experiments support the conclusion that the wall-following behavior of Drosophila is best characterized by a preference for the arena boundary, and not thigmotaxis or centrophobicity.Since the boundary preference could derive from highly linear trajectories, we further developed a simulation program to model the effects of turn angle on the boundary preference.Hence, low turn angled movement does not drive the boundary preference.

View Article: PubMed Central - PubMed

ABSTRACT
Drosophila adults, when placed into a novel open-field arena, initially exhibit an elevated level of activity followed by a reduced stable level of spontaneous activity and spend a majority of time near the arena edge, executing motions along the walls. In order to determine the environmental features that are responsible for the initial high activity and wall-following behavior exhibited during exploration, we examined wild-type and visually impaired mutants in arenas with different vertical surfaces. These experiments support the conclusion that the wall-following behavior of Drosophila is best characterized by a preference for the arena boundary, and not thigmotaxis or centrophobicity. In circular arenas, Drosophila mostly move in trajectories with low turn angles. Since the boundary preference could derive from highly linear trajectories, we further developed a simulation program to model the effects of turn angle on the boundary preference. In an hourglass-shaped arena with convex-angled walls that forced a straight versus wall-following choice, the simulation with constrained turn angles predicted general movement across a central gap, whereas Drosophila tend to follow the wall. Hence, low turn angled movement does not drive the boundary preference. Lastly, visually impaired Drosophila demonstrate a defect in attenuation of the elevated initial activity. Interestingly, the visually impaired w(1118) activity decay defect can be rescued by increasing the contrast of the arena's edge, suggesting that the activity decay relies on visual detection of the boundary. The arena boundary is, therefore, a primary object of exploration for Drosophila.

No MeSH data available.


Related in: MedlinePlus