Suppression of corticosterone synthesis alters the behavior of hippocampally lesioned rats

The suppression of corticosterone synthesis with metyrapone (25 mg/kg) reduced the hyperactivity and altered the exploratory activity of hippocampally lesioned animals (HPC) in the open field to the level of cortical and sham controls (Experiment 1). In a second experiment, corticosterone (600 micrograms/kg) pretreatment 2 h, but not 1 h, before metyrapone partially restored the hyperactivity of HPC animals that had been decreased by the corticosteroid-suppressant drug. Alterations in exploratory behavior induced by metyrapone were also prevented by corticosterone pretreatment. The results suggest that the suppression of corticosterone in hippocampally lesioned animals produces a normalization of behavior that can be prevented by pretreatment with corticosterone.     

Effects of social isolation in adulthood on odor preferences and urine-marking in male rats

Male rats isolated for 60 days in adulthood spent less time investigating odors of females and urine-marked less over these odors than did males kept in groups of three. Isolated males did not differ from grouped males in their responses to odors of unfamiliar males or their own odors. After social experience the isolated males showed an increase in urine-marking but no change in odor preferences. Individual housing therefore appears to alter olfactory communication in the same way that it does other social behaviors and these changes may be mediated by the same mechanisms.     

Indiscriminate mothering as a contextual factor in aggressive-oppositional child behavior: “Damned if you do and damned if you don’t”

Fifty-two mother-child dyads took part in a parent training program to modify coercive, antisocial child behavior. Prior to intervention, scores on 14 measures of mother-child interaction and on an index of maternal community contacts (known as insularity) were obtained for each dyad. This index was used to divide the sample into two groups (noninsular) n=21; insular n=31). The interactional measures were then compared between the groups. Insular mothers were more aversive and indiscriminate than noninsular mothers in their use of aversive behavior toward their children, while their children were more aversive than noninsular children, especially in response to aversive maternal behavior. It was concluded that research and therapeutic work with deviant families should focus not only on immediate family interactions but also on the extrafamily environment in which these interactions take place.The research data reported in this paper were generated with support of Grant No. R01-1068-58 from the National Institute of Mental Health, Crime and Delinquency Section. The first author conducted the research while supported by a grant from the University of Lausanne, Switzerland, and the Swiss National Fund for Scientific Research.     

Qualitative influences on the perception of movement: An experimental study

One of the most puzzling features of “hyperactivity” in children is the importance of activity itself. Generalized overactivity has not been found to be a valid diagnostic marker. Could some qualitative features of activity be important determinants of the perceived quantity of activity? The analogue study reported here derives from a social-psychological hypothesis that anything that makes a behavior more noticeable or distracting can create an illusion of increased movement. Subjects performed a simple cognitive task while watching short films of adult actors. Two variables were manipulated: (a) The sound level was either loud or quiet, and (b) instructions to subjects were varied so that the behaviors shown were perceived as either appropriate or inappropriate. Results strongly supported the hypothesis. Loudness and contextual inappropriateness made the films more distracting, produced higher ratings of the amount of movement observed, and led to more negative evaluations of the behaviors seen. Implications for assessment and intervention are discussed.     

Distributed memory and the representation of general and specific information

We describe a distributed model of information processing and memory and apply it to the representation of general and specific information. The model consists of a large number of simple processing elements which send excitatory and inhibitory signals to each other via modifiable connections. Information processing is thought of as the process whereby patterns of activation are formed over the units in the model through their excitatory and inhibitory interactions. The memory trace of a processing event is the change or increment to the strengths of the interconnections that results from the processing event. The traces of separate events are superimposed on each other in the values of the connection strengths that result from the entire set of traces stored in the memory. The model is applied to a number of findings related to the question of whether we store abstract representations or an enumeration of specific experiences in memory. The model simulates the results of a number of important experiments which have been taken as evidence for the enumeration of specific experiences. At the same time, it shows how the functional equivalent of abstract representations--prototypes, logogens, and even rules--can emerge from the superposition of traces of specific experiences, when the conditions are right for this to happen. In essence, the model captures the structure present in a set of input patterns; thus, it behaves as though it had learned prototypes or rules, to the extent that the structure of the environment it has learned about can be captured by describing it in terms of these abstractions.     

Potentiation and overshadowing in preweanling and adult rats

Four experiments compared the aversion acquired by 18-day-old and 60-day-old rats to a flavor that was either tasted alone or in combination, simultaneously or successively, with another flavor when paired with illness. The purpose was to study temporal variables and theoretical issues pertinent to potentiation and overshadowing while investigating ontogenetic differences in these phenomena. When either the preweanlings or the adults were presented a simultaneous compound flavor (sucrose/coffee) followed by lithium chloride-induced illness, greater sucrose aversions were found than for animals conditioned on sucrose alone--that is, potentiation. Preweanlings demonstrated greater potentiation than did adults, whether the conditioned stimulus-unconditioned stimulus (CS-US) delay was 0 or 1 hr. This potentiation was eliminated by nonreinforced presentations of the alternative CS element. Potentiation was not seen when the two flavors were presented successively as the CS; instead, overshadowing occurred. Tests of configuring by extinction procedures indicated a tendency for these animals to form a configured representation of the simultaneous compound solution. This disposition for configuring tended to be more pronounced for preweanlings than for adults. Ontogenetic differences in response to configuration, CS saliency, and generalization decrement seem consistent with at least one model of potentiation and the ontogenetic differences in potentiation seen in the present experiments.     

Reflex modification in the rat: the inhibitory effects of intensity and frequency changes in steady tones

In laboratory rats (as in humans) a low-intensity tone that precedes a high-intensity burst of noise by approximately 100 ms can reduce the amplitude of the startle reaction elicited by the burst of noise. A series of four experiments with rats investigated the relation between the inhibitory effects of tonal frequency change and the length of the silent period (gap) preceding it. The major findings were the following: (a) A gap in an otherwise continuous pure tone inhibited startle when the gap occurred approximately 100 ms prior to the noise burst. (b) Although an increase in gap duration increased the inhibition afforded by the gap, the maximum inhibition was yielded by gaps of 100 ms and greater; this maximum was equivalent to the inhibition yielded by the presentation of a postgap tone alone. (c) A shift in tonal frequency across a 10-ms gap yielded more inhibition than did the same gap with no frequency shift; again the shift yielded equivalent inhibition to the presentation of the postgap tone alone. (d) An increase in the frequency shift increased inhibition when the shift occurred across a 10-ms gap, but not when the shift occurred across a 100-ms gap.     

Adolescent pregnancy: effects of family support, education, and religion on the decision to carry or terminate among Puerto Rican teenagers

Why do some pregnant teenagers decide to carry to term while others terminate their pregnancy? This study examined the influence of family relationships and support, religion, and education on the decision to carry or to abort. A nonrandom sample of 43 pregnant Puerto Rican teenagers (21 who carried and 22 who aborted) were interviewed in 1982 using a 34-item interview schedule. It was found that girls in the carry group were more significantly influenced and supported by family and friends than were those in the abort group. Fathers were the least influential persons in both carry and abort groups, while mothers were the most influential in the carry group, and sisters in the abort group. Brothers, boyfriends, and best friends were more influential for carry girls than for abort girls. Contrary to expectations, girls in the abort group reported a greater degree of religiosity than did those in the carry group. Further, girls who received strong support from family and friends reported a higher degree of satisfaction with their decision than did those who received less support. Finally, girls in the abort group were more likely to continue their education than were those in the carry group. Overall, the findings of this study have immediate implications for research and counseling services. Practitioners should focus on the girls in conjunction with their families in order to achieve better results in both treatment and preventive services.     

Social Motives and Susceptibility to Disease: Stalking Individual Differences In Health Risks

This article reviews studies on the relation between social motives and susceptibility to physical illness. The motives examined in the studies include power motivation and affiliation motivation and their related syndromes such as inhibited power and relaxed affiliation. The subject populations include college students as well as adults. Blood pressure, self-reports of illnesses, catecholamines, and parameters of immunologic functioning are among the indices of health outcomes investigated. Taken together, these studies suggest that social motives may be importantly related to susceptibility to illness, that the power motive may be related to heightened susceptibility to illness, particularly when the person is under stress, whereas the affiliation motive may be related to diminished susceptibility to illness.     

Redundancy: a similar principle in independent adaptation techniques

The present study examined the similarities between four auditory adaptation techniques to determine whether the effects were correlated. The four adaptation techniques compared were: Simultaneous Dichotic Loudness Balance technique (SDLB; Hood, 1950), Magnitude Estimated Binaural technique (MEB; Botté, Canévet, & Scharf, 1982), Magnitude Estimated Monaural technique, (MEM; Weiler, Sandman, & Pederson, 1981), and the Monaural Reaction Time technique (RT; Davis & Weiler, 1976). Results did not show significant correlations between the four techniques, except (r = 0.39) between MEB and MEM procedures. This correlation was much less than the reliability of the measures would allow (r = 0.98 and r = 0.99, respectively). Thus, it appears that the different methods either produced different adaptation effects or measured different aspects of auditory adaptation. The normal ear apparently shows several forms of adaptation, which reduces the perceptual strength of a continuing stimulus, in favor of an intermittent, less redundant one.