Epilepsy by looking at patterns]

The author, after pointing out the rare occurence and peculiarities of pattern-sensitive forms of epilepsy, reports the case of a seven-year-old boy with infantile cerebral paresis characterized by symptomatic attacks, who was observed to show absence-like conditions when looking at small-checkered patterns of nylon fabric. Grasping and looking at such fabrics assumed the form of an addiction, with a sense of pleasure being believed to be derived therefrom. Although anticonvulsive therapy resulted in attacks of epilepsy being no longer detectable clinically and by electroencephalography, seizures were still triggered by looking at patterns. Also discussed in this article is the problem of transition from real to psychogenic attacks.     

Response bias and the measurement of choice alternation

The problem of devising a measure of alternation of choices that is independent of response bias is considered. Previous solutions are equivalent to the correction for chance guessing in the Yes/No experiment of psychophysics, and require an estimate of response bias, usually from choices on the first of two daily trials. This involves the questionable assumption that response bias is homogeneous over time or across subjects. It is suggested that spontaneous alternation is analogous to the two alternative forced choice situation of psychophysics, and the fourfold point correlation is proposed as an index of alternation that is statistically independent of response bias. Implications for interpreting the effect upon spontaneous alternation of hippocampal and other lesions are considered.     

Determination of the variation in conduction speed of motor fibers and the effects of diphenylhydantoin (Phenytoin) and diazepam (Faustan)]

The variation in the speed of conduction of motor fibers of the ulnar nerve was determined by Hopf's double-stimulus method and compared with values obtained from the duration of muscular response potentials for differently spaced points of stimulation. However, the values obtained from the difference of the duration of response potentials are inadequate since the duration of potentials cannot always be determined accurately. After a ten-day administration of faustan (15 mg per day) or phenytoin (300 mg per day) there was observed a decrease especially in the minimum rate of conduction of motor fibers of the ulnar nerve.     

Sequential effects of non-reward in a skinner box

The partial reinforcement extinction effect was examined within subjects in a simultaneous discrimination in a two bar Skinner box. Discrete trials were used, rats being required to press the bar under the illuminated cue light; one bar was correlated with 100% the other with 50% reinforcement. The three groups differed in the probability of a change in the cue light between trials during acquisition. When this probability was low, the 50% bar was preferred in extinction, while when it was higher (0.433 or 0.875) the 100% bar was preferred. These results confirm Capaldi's (1966) hypothesis of the partial reinforcement extinction effect, and support a suggested explanation of some conflicting results on partial reinforcement effects in a Skinner box.