We present here the VMB Tracking System, a novel method for tracking locomo
tor activity, posture, thigmotactic scanning behavior and social interactio
ns of up to eight animals at a time, at a high resolution (up to +/- 0.1 mm
). We used a commercially available computerized system that is considerabl
y cheaper than other available methods. This system utilizes a basic person
al computer controlling three transponders ('towers') fixed in space above
the tested area, where animals as small as rats stroll freely in their norm
al habitat or in an experimental arena. Each tower emits infra-red OR) puls
es to a transponder ('button') adhered to a plastic mount glued to a shaved
area of-skin on the animal's back. When the button detects the IR pulses i
t responds with a button-specific ultrasonic signal that is fed back to the
towers. The 3D location of the buttons is calculated by triangulation. Mov
ement parameters of each button, such as displacement trajectory, time, spe
ed and acceleration, can be displayed on-line and stored for off-line analy
sis. This system can be used to track animals in any lighting conditions, a
nd to assess drug effects on the CNS, neuromuscular junction or muscle. As
an example we demonstrate the ataxic effects of pentobarbital in rats. (C)
1998 Elsevier Science B.V. All rights reserved.