An inexpensive activity measuring device for small animals

A satisfactory device for measuring activity of rats or other small animals has been a difficult problem. Several types of instruments have given incorrect measurements or are prohibitively expensive. Photocells give the same readout to a bobbing head as for a walk over a considerable distance requiring only the interruption of a light beam. Other devices require rotation of wheels or complex integrating circuits which must be replicated or scanned and recorded for simultaneous activity measurement of many animals. The device reported here utilizes the tilting of balanced cages to actuate a single microswitch coupled to an impulse counter for each cage. The system has functioned well for several years.     

A low-force swivel connector for infusing liquids into unrestrained animals

A swivel connector for infusing liquids into catheterized animals is described. The connector turns so freely that restraints and strain relief for the catheter are unnecessary. A cylindrical acrylic body and nylon cap screw hold a rubber O ring in place, and a length of needle tubing rotates within the O ring. The only friction in the swivel is between the needle tubing and the interior of the O ring. Construction time is about 1 h. Swivels of this design have provided trouble-free service for 3 years.     

Measurement of activity in small animals using a microcomputer-controlled system

A computer-controlled system that detects spontaneous activity (locomotion and rearing) and diurnal activity rhythms in small animals is described. Automatic recording of subtotals during test periods provides data about habituation (nonassociative learning). The system is relatively inexpensive to construct. Fabricated from highly reliable circuit components, it provides replicable measures that enable comparisons between different experimental treatments to be made using parametric statistics.     

A computerized infrared monitor for following movement in aquatic animals

Reliable monitoring of the movement of small aquatic animals presents some unique problems. In the case of the larval salamander, the animal may be less than an inch long and move in sporadic short bursts. A device is described that utilizes infrared emitters and wide-band sensors inter-faced to a computer for monitoring location and movement of animals between light and dark environments over extended periods of time. The system employs a multiplexed digital input, is inexpensive, and can be easily expanded to deal with a range of monitoring problems that may occur with a wide range of both aquatic and terrestrial species.     

An inexpensive infusion pump suitable for chronic administration of liquids to restrained or unrestrained animals

A self-contained, inexpensive, disposable infusion pump is described for chronic or acute administration of solutions. The pump consists of a modified disposable syringe that is capable of delivering liquids at rates which may be varied. Pressure resulting from a chemical reaction within a chamber propels a rubber piston, which in turn expels liquids at a uniform rate.     

An electronic cine camera system for the automatic collection and analysis of high-speed movement of unrestrained animals

A system is decribed that collects visual data using a solid-state photodiode image sensor at rates of up to 600 frames/sec in a binary format suitable for image-analysis techniques. Of particular interest is the system’s ability to analyze high-speed movement of animals without prior modification of the subject (e.g., attachment of lamps or reflectors to the subject).     

A reliable method for continuously monitoring motor activity in unrestrained squirrel monkeys

A simple, reliable, and inexpensive method for measuring spontaneous motor activity in unrestrained squirrel monkeys is described. In this method, the home cage is suspended within a wooden enclosure in a way that allows the cage to swing in any lateral direction. This movement is recorded by two brass cylinders connected to the home cage and to the fixed wooden enclosure, respectively. The brass cylinders act as electrical contacts that serve to trigger an electronic recording device. The method is extremely sensitive.     

A microcomputer-controlled system for measuring reactivity in small animals

A microcomputer-controlled system has been designed for measuring reactivity in small laboratory animals. This system uses a microcomputer to trigger an acoustic signal, which is fed to a loudspeaker through an audio power amplifier. An animal’s acoustic startle response is recorded using a moving-coil loudspeaker as a movement transducer. The transducer output is coupled to a peak-hold circuit that records the maximum voltage generated by the animal’s response. After conversion to digital form, the data for each stimulus presentation are stored and then printed when all trials have been completed.     

Technique for monitoring activity in free-moving animals

A techique is described for measuring activity by monitoring the rotational movements of a commutator. to which animals might be connected for other experimental purposes.     

A microwave doppler radar activity monitor

The general requirements of an activity monitor are listed. The principle of operation of microwave doppler radar is described. The circuitry is given for a sensitive radar activity monitor that works by detecting the doppler shift in microwaves reflected from a moving animal. The apparatus is automatic and nonintrusive, and it gives an output suitable for direct computer analysis. A high level of concordance is found with manual observation. A simple means of calibrating the device is described.     

The use of an ultrasonic monitor for recording locomotor activity

An ultrasonic activity monitor has been designed that can be used to detect motion in air or within an aquarium. Stability and linearity of response of the monitor have been measured. The system has been used to examine activity rhythms of the marine invertebrate,Octoput ornatus Gould.