Effect of electrical stimulation amplitude on dynamic behavior of mice during evacuation

Abstract

Profound examination of the dynamic behavior of pedestrians during evacuation can significantly reduce the number of associated accidents. Conducting experiments on animals can help obtain deep insight into the dynamic behavior of pedestrians. Previous experiments using insects, such as ants and woodlice, showed large differences between the dynamic behaviors of insects and humans. However, systematic studies on the behavioral characteristics (e.g., velocity) of mice under electrical stimulation conditions have not been reported. Therefore, this study was conducted to investigate changes in the dynamic behavior of mice during evacuation caused by electric shock. Electrical stimulation was supplied through their feet during evacuation. The average velocity, desired velocity (maximum instantaneous velocity), average velocity in the congestion zone, and escape time were measured and analyzed. According to the results, the desired velocity and escape time increased in proportion to the amplitude of the electrical stimulation; however, the average velocity decreased. Consequently, the level of emergency of mice is affected by both the amplitude of electrical stimulation and the number density in congestion area as in human experiments.

Keywords: Desired velocity; Electric shock; Evacuation; Mice experiments.

Fig. 1

Schematics and photographs of experimental devices.

Fig. 2

Snapshots of mice evacuation. The partition was opened after 1, 5, and 10 s from left to right, and the electric shock amplitude was (a) 40, (b) 45, (c) 50, and (d) 55 V.

Fig. 3

Evacuation time for a group of 50 mice.

Fig. 4

Distribution of average velocities in a group of 50 mice at different electric stimulus amplitudes.

Fig. 5

Distribution of the maximum instantaneous velocity in a group of 50 mice at different electric stimulus amplitudes.

Fig. 6

Distribution of the average velocities in a group of 50 mice in the congestion zone.

Fig. 7

Distribution of the evacuation time in a group of 50 mice at different electric stimulus amplitudes.

Fig. 8

Comparisons of the average (a) evacuation time and (b) velocity between the groups with 50 and 15 mice.