A Fully Automated and Highly Versatile System for Testing Multi-cognitive Functions and Recording Neuronal Activities in Rodents

Abstract

We have developed a fully automated system for operant behavior testing and neuronal activity recording by which multiple cognitive brain functions can be investigated in a single task sequence. The unique feature of this system is a custom-made, acoustically transparent chamber that eliminates many of the issues associated with auditory cue control in most commercially available chambers. The ease with which operant devices can be added or replaced makes this system quite versatile, allowing for the implementation of a variety of auditory, visual, and olfactory behavioral tasks. Automation of the system allows fine temporal (10 ms) control and precise time-stamping of each event in a predesigned behavioral sequence. When combined with a multi-channel electrophysiology recording system, multiple cognitive brain functions, such as motivation, attention, decision-making, patience, and rewards, can be examined sequentially or independently. Video LinkThe video component of this article can be found at https://www.jove.com/video/3685/ Protocol System OverviewThe system comprises three main components: (1) a double-walled sound proof room (Industrial Acoustical Company, Bronx, New York); (2) a multiple channel electrophysiological recording system (Neuralynx, Bozeman, MT); and (3) a fully automated, customized behavioral testing system from the Med Associates Inc. (St. Albans, VT). Figure 1A, the operant chamber is located inside the sound-proof room. A commutator (Model SL-36, Dragonfly Research and Development, Inc., Ridgeley, West Virginia) for connecting cables from headstage to the electrophysiological recording system (Figure1A-a), and a video camera for monitoring and recording animal behaviors are mounted above the operant chamber (Figure1A-b). As shown in Custom-Designed Operant ChamberThe custom-designed, acoustically transparent operant chamber (Figure1A-d) consists of three acoustically transparent walls and one modularoperation panel ( Figure 1B). Three speakers (Cage Tweeter, ENV_224BM, Med Associates) mounted on the top of the middle and two side panels are used for emitting auditory cues. Auditory cues are generated by a calibrated, programmable audio generator (ANL-926). A stimulus light (ENV_221M) and two triple-stimulus LED displays (ENV_222M) are located on the middle and side panels, respectively. These stimulus lights can be used for auditory-visual multi-sensory behavioral tests. A nose poke device with three color LED lights (ENV_114M) is mounted at the bottom of the middle panel. An infrared detector installed within the nose poke unit is used to signal nose poking and holding period. The LED lights within the nose poke unit can be used for training nose-hold inside the hole. A movable response lever (ENV_112CM) is mounted on each side of the operant panel. The mobility of these levers allows flexible control of the presence of the levers, which can be effectively used for both initial task training and the study of several important cognitive functions of the brain (see below). Four ...

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