A pseudorandom noise generator for use in auditory research

A noise generator that is capable of delivering long-duration samples of reproducible noise is described. The noise is generated as a pseudorandom telegraph waveform but may be filtered so that its amplitude distribution is approximately Gaussian. The design and construction of the generator are detailed and a few possible applications are given.     

A Plexiglas helmet and catheter protection assembly for chronic intravenous administration of drugs in small primates

A restraint and catheter-protection system consisting of a Plexiglas helmet and a nylon-tubing protector line has been developed to permit the long-term study of drug self-administration in monkeys. Frequent observations of monkeys in the system over a period exceeding a year have shown that the technique satisfies the requirements for long-term study of drug administration through an indwelling catheter and avoids several recurring problems inherent in other protection systems. Additional applications of the helmet and protector line are discussed.     

An inherent problem in certain constant-current stimulators

A basic and potentially dangerous problem that may occur in the use of triggered constant-current generators for stimulation is discussed in the general case. A solution with schematic illustration is presented for one specific constant-current generator, the CCS-1A manufactured by Electronics of Life Sciences, Inc.     

Non-interaction of ventromedial and lateral hypothalamic mechanisms in the regulation of feeding and hoarding behaviour in the rat

Lesions of the hypothalamic ventromedial nucleus (VMN) led to an immediate increase in food intake but not to any increase in hoarding activity. Later, when subjects were very obese, they failed to hoard even in response to a 16-hr. deprivation schedule, although this schedule did produce hoarding if body weights were held at, or were brought down to, preoperative levels. These results indicate that the lateral hypothalamic mechanism responsible for hoarding and feeding responds to long-term nutritional factors, and that it is not directly affected by the short-term satiety mechanisms in the VMN. These findings support the hypothesis (a) that even “non-physiological” activities (e.g. hoarding, exploration) are motivated by physiological needs, and (b) that the reason these activities do not ordinarily covary with physiological drives is that, unlike the physiological drives, they are not subject to inhibition by the hypothalamic satiety mechanisms.