On the time constants of tachistoscopes

The time constants of commercially available, electronic tachistoscopes are shown to be much poorer than is widely assumed. When a band near the centre of the visible spectrum is isolated, the output of a typical tachistoscope lamp takes approximately 18 ms to reach 90% of its asymptotic value; the time to decay to 10% is also typically 18 ms and we demonstrate conditions under which the decaying trace remains visually effective against a dark field for more than 40 ms after the nominal offset of the lamps.

Many reports of tachistoscopic experiments published in the last two decades must be quantitatively in error; and we provide examples of experiments where qualitative conclusions may have been drawn invalidly.     

A neurophysiologic model for aggressive behavior in the cat

A neurophysiologic model for aggessive behavior in the cat is proposed. Stimulus-bound and seizure-bound aggression was evaluated in relation to limbic and basal ganglia induced seizures (after-discharges). Electrically induced limbic and basal ganglia afterdischarges were used because they are known to implicate septohypothalamic sites from which aggression can be elicited by direct stimulation. The occurrence of behavioral aggression is correlated with the discharge characteristics of a single discharging system and with two interacting discharging systems. Aggression is composed of autonomic and somato-motor components which poses relatively low and high thresholds, respectively, for their activation. Aggression occurring during a combined septum and amygdala discharge was more intense and prolonged than with a septum discharge alone. Participation of a slow frequency discharging basal ganglia system activated seizurebound aggression in an otherwise nonaggressive limbic seizure. The limbic and basal ganglia stimulations and after-discharges lowered the excitability threshold of the aggression system and made it more vulnerable to being activated by external stimuli, such as visual and auditory stimuli. These observations are reminiscent of patients with aggressive behavior associated with psychomotor seizures.     

Personality and conditioning: Factors of classical CR acquisition and extinction and their relationship to personality types

Anumber of psychophysiological, cognitive and personality measures, and classical appetitive and aversive SR acquisition and extinction rates were taken from a sample of 25 male undergraduate volunteers. Principal Components Analysis of the data revealed general acquisition and extinction factors which were indexed by the psychophysiological variables. Regression analyses showed additionally that Eysenck’s E-I dimension predicts both acquisition and extinction rates, and that imagery may be an important mediational variable in CR acquisition.     

Learning capacities during sleep: A preliminary study in a group of schizophrenic inpatients

The relationship between sleep and learning processes is analysed in a sample of schizophrenic patients, starting from more recent hypotheses about the function of REM sleep in learning and memory processes. This is done by means of two experiments: in the first AA. evaluate the possibility to elicit a simple motor conditional reflex acquired during daytime in different sleep stages. With the second experiment daytime learning performances are evaluated with and without a reinforcement administered during REM sleep. Results for the first experiment underline a qualitative difference between REM and nREM sleep in a reflexological perspective. In nREM sleep the conditional response is better maintained than in REM sleep. The second experiment confirms the possibility to improve daytime learning performances after an additional presentation of learning material in REM. The joint study of sleep abnormalities and learning and cognitive impairment in schizophrenic patients is finally suggested.     

A multipurpose activity platform utilized in the open-field setting

An automated multipurpose activity platform (MAP) that can be used to measure activity in the horizontal plane is described. Detection of the position of a small-bodied animal is based on completion of an electronic circuit in one or several cells of a 21 by 21 matrix below the floor. The MAP is constructed on the basis of an 11 by 11 matrix, but, through electronic averaging, operates functionally on the basis of a 21 by 21 matrix. The MAP has no built-in data storage facility and needs to be interfaced with a recording system. The system has been successfully utilized in measuring open-field activity of the rats.     

Comparative evaluation of the Job Club program with welfare recipients

About 1000 WIN welfare clients were selected in five cities: Harlem, New Brunswick, Milwaukee, Wichita, and Tacoma, and half were randomly assigned to the Job Club program. Of the continuing clients, 87% of the Job Club sample obtained jobs vs 59% of the Control sample at the 12-month follow-up and 80 vs 48% at 6 months. The Job Club was more effective in each of the five cities, for men and women, for high school graduates or dropouts, for blacks, whites, and Spanish, for handicapped or nonhandicapped, veterans or nonveterans, the young and the older, and for those required to participate as well as those who volunteered. The jobs obtained by the Job Club clients were comparable to the Control clients' jobs in terms of mean salary, full-time status, and type of job, and were more likely to be enduring, nonsubsidized, and obtained by the job-seeker's own efforts. Job Club members obtained employment in a median of six sessions (mean of 11); 90% obtained jobs within 23 sessions. Follow-up questionnaire data indicated comparable job retention in the two samples but slightly greater advancement and job satisfaction for the Job Club clients. The method appears to assure employment to virtually all participating welfare clients.