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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 opaque internal corners. (A). An arena was constructed with two intersecting walls that generated four internal corners. (B). The mean time spent in the 4-cm2 sector in the center of the arena was determined with four combinations of opaque internal and external vertical surfaces. In each case, the flies spend more time in the center zone in the arena with internal corners than the control open arena of the same size. When the outer wall was clear and the internal walls were opaque, the flies spent even more time in the center. (C). Only in this last experiment with the opaque internal corners, there was a significant interaction between mean percentage of time spent in the center and time in the arena (F9620 = 2.380, P = 0.012). This time dependence leads to an inverse relationship between amount of specific exploration and percentage of time spent in the corner. n = 32 for each arena.
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fig02: A time-dependent preference for opaque internal corners. (A). An arena was constructed with two intersecting walls that generated four internal corners. (B). The mean time spent in the 4-cm2 sector in the center of the arena was determined with four combinations of opaque internal and external vertical surfaces. In each case, the flies spend more time in the center zone in the arena with internal corners than the control open arena of the same size. When the outer wall was clear and the internal walls were opaque, the flies spent even more time in the center. (C). Only in this last experiment with the opaque internal corners, there was a significant interaction between mean percentage of time spent in the center and time in the arena (F9620 = 2.380, P = 0.012). This time dependence leads to an inverse relationship between amount of specific exploration and percentage of time spent in the corner. n = 32 for each arena.

Mentions: We next examined the antecedent for corner preference by placing four 90° corners, formed by two perpendicular intersecting walls extending 3 cm from the center point, in the center of the arena (Fig. 2A). If the corners are strongly preferred thigmotactic surfaces, the flies would leave the boundary and spend more time within the center of the arena. Although the internal corners significantly increased the amount of time in proximity to the center (t = –5.909, P-value < 0.0001, df = 31), the percentage of time spent (∼6%) was far below that of external corners (∼50%; Fig. 2B), suggesting the presumptive preference for the internal corners is less than the preference for the concave arena boundary. In these experiments, we also examined the preference for different combinations of darkened walls. For all the different combinations, the internal corners significantly increased the amount of time in proximity to the center (dark edge and dark corner: t = –3.03, P-value = 0.014, df = 31; dark edge and clear internal corner: t = –4.239, P-value = 0.0003, df = 31; clear edge and dark internal corner: t = –17.587, P-value < 0.0001, df = 31). In the first three conditions, the total time in the arena did not significantly affect the percentage of time spent in proximity to the internal corners (clear edge and clear corner: F9, 620 = 0.736, P-value = 0.676; both edge and corner dark: F9, 620 = 0.442, P-value = 0.912; dark edge and clear corner: F9, 620 = 0.111, P-value = 0.999). However, when the boundary wall is clear and the internal walls are opaque, the flies spend increasingly more time in close proximity to the internal corners as the exploratory activity phase is attenuated (Fig. 2C; F9, 620 = 2.380, P-value = 0.012). Hence, exploration supersedes the strong preference for the darkened internal corner. Drosophila also strongly prefer the arena boundary to the clear internal corners.


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 opaque internal corners. (A). An arena was constructed with two intersecting walls that generated four internal corners. (B). The mean time spent in the 4-cm2 sector in the center of the arena was determined with four combinations of opaque internal and external vertical surfaces. In each case, the flies spend more time in the center zone in the arena with internal corners than the control open arena of the same size. When the outer wall was clear and the internal walls were opaque, the flies spent even more time in the center. (C). Only in this last experiment with the opaque internal corners, there was a significant interaction between mean percentage of time spent in the center and time in the arena (F9620 = 2.380, P = 0.012). This time dependence leads to an inverse relationship between amount of specific exploration and percentage of time spent in the corner. n = 32 for each arena.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3345355&req=5

fig02: A time-dependent preference for opaque internal corners. (A). An arena was constructed with two intersecting walls that generated four internal corners. (B). The mean time spent in the 4-cm2 sector in the center of the arena was determined with four combinations of opaque internal and external vertical surfaces. In each case, the flies spend more time in the center zone in the arena with internal corners than the control open arena of the same size. When the outer wall was clear and the internal walls were opaque, the flies spent even more time in the center. (C). Only in this last experiment with the opaque internal corners, there was a significant interaction between mean percentage of time spent in the center and time in the arena (F9620 = 2.380, P = 0.012). This time dependence leads to an inverse relationship between amount of specific exploration and percentage of time spent in the corner. n = 32 for each arena.
Mentions: We next examined the antecedent for corner preference by placing four 90° corners, formed by two perpendicular intersecting walls extending 3 cm from the center point, in the center of the arena (Fig. 2A). If the corners are strongly preferred thigmotactic surfaces, the flies would leave the boundary and spend more time within the center of the arena. Although the internal corners significantly increased the amount of time in proximity to the center (t = –5.909, P-value < 0.0001, df = 31), the percentage of time spent (∼6%) was far below that of external corners (∼50%; Fig. 2B), suggesting the presumptive preference for the internal corners is less than the preference for the concave arena boundary. In these experiments, we also examined the preference for different combinations of darkened walls. For all the different combinations, the internal corners significantly increased the amount of time in proximity to the center (dark edge and dark corner: t = –3.03, P-value = 0.014, df = 31; dark edge and clear internal corner: t = –4.239, P-value = 0.0003, df = 31; clear edge and dark internal corner: t = –17.587, P-value < 0.0001, df = 31). In the first three conditions, the total time in the arena did not significantly affect the percentage of time spent in proximity to the internal corners (clear edge and clear corner: F9, 620 = 0.736, P-value = 0.676; both edge and corner dark: F9, 620 = 0.442, P-value = 0.912; dark edge and clear corner: F9, 620 = 0.111, P-value = 0.999). However, when the boundary wall is clear and the internal walls are opaque, the flies spend increasingly more time in close proximity to the internal corners as the exploratory activity phase is attenuated (Fig. 2C; F9, 620 = 2.380, P-value = 0.012). Hence, exploration supersedes the strong preference for the darkened internal corner. Drosophila also strongly prefer the arena boundary to the clear internal corners.

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