A random-pulse generator with adjustable pulse duration

An electronic device for generating random pulses of adjustable duration within a minimal and maximal interval boundary is described. The instrument is useful in electro- and psychophysiological research where randomization of stimulus input is required.     

Crossbreeding and special handling of genetically nervous dogs

In studies of a healthy (A) and a nervous (E) genetic strain of pointer dogs, two techniques were utilized to determine environmental and hereditary influences. These were (1) reciprocal crossbreeding to females from each strain, and (2) split litters with special handling and human attention to one-half of each litter of nervous strain origin from birth through age six months. It is not possible to attribute the nervous behavior to an environmental mother effect since crossbred AE and EA offspring were highly similar on behavior tests of brief exploratory activity, rigid posturing to a loud noise and human avoidance behavior. Furthermore, special handling had almost no success in normalizing the responses of the nervous dogs in the behavior tests or in heart rate response to Effect-of-Person procedures. The results show that the biologic origin of the dogs is the most likely source of the nervousness; this has placed severe limits thus far on attempts to attenuate the condition.     

Coronary blood flow in dogs: Effect of person

Experiments on dogs with electromagnetic flow probes implanted around a coronary artery and the ascending aorta indicate that the entry of a person into the experimental chamber can cause a remarkable increase in coronary blood flow. Heart rate usually increases considerably, blood pressure increases only slightly, while aortic blood flow increases at variable times before and after coronary blood flow. It is not yet clear whether these cardiovascular effects are due purely to “effect of person” or to conditioning, with the person as the signal for the momentary coronary occlusion (which the person subsequently accomplishes by manually closing a snare).     

Can a small dedicated machine find happiness in a company that pioneered time-sharing?

In the context of an automated psychophysical laboratory, the adequacies and inadequacies of a small computer are discussed. Attention is given to the rationale for choosing the implementation in particular a dedicated small system as opposed to time-shared use of a larger system. The variables discussed include cost, flexibility, language level, and storage capabilities in addition to reliability. A compromise position that appears most viable for the future is also suggested.     

A combination stereotaxic drill press and electrode carrier

A method of transforming a vertical rack and pinion-type electrode slide into a miniature drill press is described. Advantages of the instrument are noted and several applications suggested. Specifications are included for the aluminum electrode mold for cat cortical electrode casts.