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.     

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.     

An inexpensive universal feeder suitable for small numbers of large rations

This report describes a simple universal feeder designed for operant conditioning applications in zoo settings. The apparatus delivers up to six large rations of food. It is portable, easily serviced, and can be constructed in a modest carpentry shop.     

An inexpensive automated system for the measurement of rotational behavior in small animals

A reliable, low-cost automated system for the quantification of rotational behavior from up to 10 subjects simultaneously is described. The system resolves quarter and full turns to the left and right, and can relay data to another computer for statistical analysis. The system is easily constructed from simple and inexpensive components, including the computer, that total less than $1,000 and can be used with a variety of different test chambers.     

A simple,inexpensive, liquid-tight swivel connection for use in chronic infusion systems

This note describes the fabrication of a simple, inexpensive, liquid-tight swivel joint for twist-free coupling of small, freely moving animals to infusion systems. The device uses a disposable hypodermic needle and syringe as the main components, and fabrication requires only readily available hand tools and minimal mechanical expertise.     

A simple technique for delivering liquids directly to the mouth of an unrestrained rat

A simple surgical procedure is described that makes it possible to deliver liquids directly into the mouth of a freely mobile rat. Data presented show that an 8% sucrose solution delivered by this technique is an effective reinforcer in a variety of simple and discriminative schedules of reinforcement.     

An inexpensive experiment controller for stand-alone applications or distributed processing networks

An inexpensive microprocessor-based experiment controller available as a commercially produced bare printed circuit board is described. It provides for up to 8 inputs and 40 outputs. An 8K Experiment Control BASIC (ECBASIC) and a compiled Experiment Control Language (ECL) are also available. Both languages have internal structures that enable time and responses to be dealt with in a very convenient and error-free manner. Time and response count are automatically incrementing variables that need only to be tested by the user program. ECBASIC provides a 10-msec accuracy, whereas ECL provides a l-msec accuracy. ECL provides extensive support for event-driven programs. The board and software are designed to provide an orderly migration from a stand-alone controller running ECBASIC as a relay-rack replacement, to a network of ECBASIC machines on a small computer, to a true error-checking network of ECL machines on a time-sharing operating system of a large computer. Network communication is over the three wires of a single unmodified RS232 asynchronous serial communication line.     

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).     

An automatic feeder for liquids and wet or dry solids

An inexpensive and simple, remote-control conveyor-belt feeder is described. The feeder handles liquids and wet or dry solids.     

An inexpensive circuit for beta,alpha, theta,or delta EEG biofeedback

An inexpensive circuit is described for EEG biofeedback or measurement. The circuit is designed to interface easily with most basic EEG machines. It taps the output from a single recording channel of the basic EEG instrument and provides the following for each EEG band (beta, alpha, theta, and delta): (a) very selective bandpass discrimination, (b) variable center frequency, (c) variable threshold at which feedback will be provided, or the measurement made, and (d) use with any biofeedback stimulus or measurement device that one wishes to switch contingent with S’s EEG rhythms.     

To eat or not to eat: implications of the attentional myopia model for restrained eaters

The attentional myopia model of behavioral control was tested in a study of food consumption by chronic dieters. According to the model, when individuals' attentional capacity is limited, their behavior will be disproportionately influenced by highly salient internal and external cues to the exclusion of more distal stimuli. In situations that normally feature conflicting behavioral pressures, such a state of narrowed attention is likely to result in abnormally disinhibited behavior when cues promoting action are more salient and to result in abnormally restrained behavior when inhibiting cues are more salient. In addition to supporting the predictions of the model, this study provided the first evidence for enhanced behavioral control under conditions of limited attention. Participants' responses to a thought-reporting measure also provided evidence for the role played by attentional myopia in the control of eating. Implications for a broad array of regulatory successes and failures are discussed.     

An inexpensive electro-fistular swivel for negative feedback control of self-stimulation

A swivel was developed for concurrent intraorganismic fluid injection and intracranial electrical stimulation of the unrestrained rat. Effects of various intragastric injections on bar-pressing maintained by electrical stimulation of the hypothalamus were studied. In some subjects, intragastric injections of either water or milk decreased the rate of responding. This decrease resulted from pauses in responding rather than from decreases in the local rates of responding. The decrement in responding occurred at a lower gastric volume during milk injection than during water injection. In other subjects, however, neither water, milk, nor 32% sucrose injections affected the rate of self-stimulation.     

An inexpensive infrared detector to verify the delivery of food pellets

The reproducibility of experimental outcomes depends on consistent control of independent variables. In food-maintained operant performance, it is of utmost importance that the quantity of food delivered is reliable. To that end, some commercial food pellet dispensers have add-on attachments to sense the delivery of pellets. Not all companies, however, offer such add-ons. Aside from availability, cost and temporary reduction in throughput may be a problem for smaller labs. The present paper outlines our recent development of a simple, inexpensive infrared device to detect and confirm the delivery of pellets. The in-line construction of the detector routes the falling pellet through a barrel so that it passes between an infrared emitter and receiver. The circuitry was designed to be compatible with all commercially available behavioral measurement systems, and so may be retrofit to any existing system. Our tests with the detector so far have shown that it is 100% accurate in detecting pellet delivery. The individual unit cost is approximately 25 dollars. The low cost and versatility of the device offer an easy method to ensure the integrity of food delivery in operant settings.     

A technique for chronic recording of systemic arterial blood pressure in the unrestrained rat

A technique is described for the chronic recording of systematic arterial blood pressure, respiration, and heart rate in the unrestrained rat. The surgical implantation and anchoring procedures described are compatible with the delivery of noxious electric shock and/or rewarding intracranial brain stimulation as reinforcement. Data on catheter patency are analyzed in 65 rats participating in a variety of experiments on the instrumental and classical conditioning of blood pressure responses. The results indicate that it is difficult to maintain satisfactory catheter performance beyond 2 weeks.