Acquisition of matching-to-sample performance in rats using visual stimuli on nose keys.

Steady and blinking white lights were projected on three nose keys arranged horizontally on one wall. The procedure was a conditional discrimination with a sample stimulus presented on the middle key and comparison stimuli on the side keys. Three rats acquired simultaneous "identity matching." Accuracy reached 80% in about 25 sessions and 90% or higher after about 50 sessions. Acquisition progressed through several stages of repeated errors, alteration between comparison keys from trial to trial, preference of specific keys or stimuli, and a gradual lengthening of strings of consecutive trials with correct responses. An analysis of the acquisition curves for individual trial configurations indicated that the matching-to-sample performance possibly consisted of separate discriminations.     

A one-trial non-shock passive avoidance task for rats

Apparatus and procedure are described for providing a one-trial nonshock passive-avoidance task.     

A nonobtrusive heart rate telemetry system for rats

A harness for recording heart rate (HR) from unrestrained rats and an inexpensive FM transmitter for broadcasting high-resolution EKGs are described. The harness, which employs surface electrodes rather than skin pins or implanted electrodes, is especially valuable for recording HR over extended periods of time. Because it is comparatively free of noise generated by the animal’s activity, the system is applicable to a wide range of experimental conditions. Sample HRs obtained from three strains of rats while engaging in different behavioral categories are presented.     

A low-stress restraint procedure for EEG acquisition in awake rats

A restraint procedure was developed to reduce movement-related artifacts during the acquisition of EEG data from unanesthetized, unparalyzed rats. It combines the low-stress properties of a cloth restraint bag with the improved immobility of a rigid restraint device. The spontaneous behavior of the rat facilitates both the induction of and the subsequent release from restraint.