Fig. 1.

Drawing of the experimental setup. The interior of the recording chamber and the cubic frame housing the field coils of the magnetic search coil system are covered with foam to attenuate acoustic reflections; some panels have been removed for illustrative purposes. A cat is shown inside a canvas bag on a platform with its head fixed from behind by the holding bar. This animal was prepared for physiological recordings with a microdrive mounted on a recording chamber on top of the head. Multiple acoustic speakers are mounted in front of the cat behind a black cheesecloth curtain with LEDs positioned at the center of most of the speakers.