The APA is a circular metal arena shock grid underneath a rotating arena. The subjects are allowed to explore the arena while avoiding a prohibited sector using visual cues in and around the arena. Punishment in the form of shock is delivered to the subject if it enters the prohibited sector. Passive avoidance is observed when the arena is not rotating while active avoidance is observed when the arena is rotating.
The SCI device is constructed using a steel impounder inserted into a Teflon base. The impounder is attached to the end of the hollow tube by a horizontal pin to guide the weight and to prevent it from bouncing on impact. The weight is made of Teflon coated stainless steel and is supported by a removable pin which is also used to release the weight. Rod magnet is used for retrieval of the weight after the injury.