Effects of hippocampal stimulation on acquisition, extinction and generalization of conditioned suppression in the rat.

Rats implanted with electrodes in the dorsal or ventral hippocampus received posttrial stimulation in training sessions with footshock reinforcement. Afterdischarges without overt seizures were consistently without effect on the rate of acquisition of suppression of licking during an auditory conditioned stimulus (CS), although conditioning was retarded by the delivery of distracting stimuli following footshock. The rate of conditioning remained insensitive to elicitation of dorsal hippocampal afterdischarges (DHAD) despite subsequent alterations of session length, intertrial interval and preexposure to the CS. However, faster extinction of suppression occurred following DHAD, suggesting a limited but essential role of the hippocampus in addressing stored information.     

Personality research: components of variance attributable to the person and the situation.

Studies involving personality and situational variables were surveyed. Studies permitting determination of main effects and interactions involving these variables have increased since 1950. In one comparison, situational main effects were significant in 65.5% of the cases, whereas the figure was 31% for individual difference variables and 59.9% for interactions. In another comparison, 35% of situational main effects accounted for more than 10% of the variance, compared with 29% for personality indexes; 19% of the situational variable effects accounted for more than 20% of the variance, compared with 14% of the personality main effects. Low percentages of variance were accounted for by all variables investigated: situational, personality, demographic, and interactions among these variables.     

A common factor in the MMPI scales of married couples.

Using canonical analysis, a common factor in the MMPI scales of husbands and wives was found. The Sc, Pd, and Hs scales for both the husbands and the wives contributed heavily to the relationship. Other scales contributing to the correlation between the personality components of the pairs were F, Hy Pt, and Si for the husbands and Pa for the wives. The results were interpreted as indicating areas of homogeneity and heterogeneity in the personalities of married couples.     

Control of echolalic speech in psychotic children

Immediate echolalia, a common language disorder in psychotic children, was studied in a series of replicated single-subject designs across six schizophrenic and five normal children. In Experiment 1, each child was presented with several questions and commands, some of which set the occasion for specific, appropriate responses and some of which did not. The former were referred to as discriminative stimuli and the latter, as neutral stimuli. The psychotic children tended to echo the neutral stimuli while responding appropriately to the discriminative stimuli; the normal children, in contrast, typically echoed neither type of stimulus. In Experiment 2, three psychotic children were taught appropriate responses to each of several neutral stimuli. Following this training, the children generally responded appropriately to these stimuli without echoing. A plausible interpretation of these results is that the neutral stimuli were initially incomprehensible or meaningless to the children (whereas the discriminative stimuli were comprehensible or meaningful) and that verbal incomprehensibility may be one important determinant of immediate echolalia. Finally, the results are noteworthy in that they isolate a sufficient treatment variable (i.e., the reinforcement of alternative, nonecholalic responses) for eliminating instances of this language anomaly.     

APE: average potential evaluation software for the LAB-8 system

A paper-tape software system is described which allows the addition and/or subtraction of signal averaging data from the DEC advanced averager program. This pooled averaging data may be plotted, printed, or punched. A DEC LAB-8 system with 4K memory and high-speed reader/punch are required. Several examples of the application of the system to human evoked brain response data are presented, and the application of the system to other problems is discussed.     

On microprocessor-based computers

Economical microprocessor-based computers have been recently developed by Motorola and Control Logic, Inc. Apparently, in response to the price competition, DEC has introduced the PDP-8/A, incorporating the memory characteristics of the microprocessor-based computers. Relative to older minicomputers, the microprocessor-based systems and the PDP-8/A “miniprocessor” require more time to execute an experimentally useful task. However, their real-time operating characteristics would appear to be sufficient for on-line use in behavioral control and data acquisition. The PDP-8/A’s compatibility with older models of the PDP-8 series enables it to use previously developed software, but, for purposes of software development, the microprocessor systems offer a more powerful architecture and instruction set.