Age-Related Changes in Plasma Catecholamine Responses to Acute Swim Stress

Young adult (3 months) and aged (22 months) Fischer 344 male rats were prepared with chronic tail artery catheters. Three days after surgery, rats were exposed acutely to swim stress at 20, 25, 30, or 35°C for 15 min. Blood samples were obtained from each rat under basal conditions, at the end of the swim stress episode, and 15, 30, and 45 min after swim stress. Basal plasma levels of norepinephrine and epinephrine (EPI) were similar for 3- and 22-month-old rats. In contrast, plasma catecholamine responses of aged rats were significantly greater than those of young adult rats following swim stress at 20 and 25°C. Plasma catecholamine responses were similar for rats of the two ages following swim stress at 30 or 35°C. These findings indicate that aged rats have exaggerated sympathetic-adrenal medullary responses to acute swim stress at the lower water temperatures. Given the modulatory effects of plasma EPI on memory, these age-related alterations in plasma catecholamine responses to acute swim stress may influence spatial memory performance of rats in the Morris water maze.     

Daydreaming and curiosity: stability and change in gifted children and adolescents

Developmental differences in daydreaming and curiosity based on cross-sectional data have been reported, but longitudinal data are lacking. Patterns of longitudinal stability and change in two intellectual styles, daydreaming and curiosity, in gifted children and adolescents are described in this paper. Seventy-four intellectually gifted children attended a special program during two consecutive summers. Self-reports of their frequency of and attitudes toward daydreaming and two measures of their curiosity were obtained each year. The findings suggest a pattern of both change and stability in intellectual styles over time. Measures which tap the content of daydreams changed over time, but measures of process or ways of relating to the environment, such as curiosity and frequency of daydreaming, were fairly stable.     

Blood glucose and brain function: interactions with CNS cholinergic systems

We recently found that glucose injections attenuate amnesia and hyperactivity produced by scopolamine, a muscarinic antagonist. The present study examined whether glucose would augment behavioral effects produced by a muscarinic agonist, physostigmine. In experiment I, doses were first determined for which neither glucose (10 mg/kg) nor physostigmine (0.05 mg/kg) altered scopolamine-induced hyperactivity. However, combined glucose-physostigmine injections significantly reduced scopolamine hyperactivity. Experiment II evaluated the effects of glucose on physostigmine-induced tremors. Glucose (10, 100, and 250 mg/kg) or saline injections were given 20 min before physostigmine injections (0.4 or 0.05 mg/kg). Observations of glucose effects on the severity of physostigmine-induced tremors were then obtained at 5-min intervals for 25 min after physostigmine injections. Glucose (100 mg/kg) significantly facilitated the onset of tremors when injected before either dose of physostigmine, and augmented (at 100 and 250 mg/kg) tremor severity when injected before the lower dose of physostigmine. These findings indicate that glucose can facilitate the actions of a cholinergic agonist on two behaviors, locomotor activity and tremors, adding support to the view that circulating glucose levels can modulate central cholinergic function. More generally, the results provide additional evidence that circulating glucose levels can influence brain function.     

A COMPARISON OF VIETNAMESE-AUSTRALIAN AND ANGLO-AUSTRALIAN MOTHERs' BELIEFS ABOUT INTELLECTUAL DEVELOPMENT*

Vietnamese- and Anglo-Australian mothers' beliefs about intelligence and its development were obtained through a structured interview. Twenty-five working-class Vietnamese, 32 working-class and 39 upper-middle-class Anglo mothers of five-year-old children were asked about the heritability and stability of intelligence, its importance in different life domains and the roles of parents and teachers in developing intelligence. Developmental timetables for the acquisition of certain intellectual abilities were also elicited. Culture emerged as a significant influence on mothers' beliefs considerably more than did social class or sex of their child. Vietnamese mothers perceived intelligence as more important than did Anglo mothers, had a more narrowly focused view of education and intellectual development, and expected later acquisition of intellectual abilities. These differences are consistent with traditional Vietnamese values.     

The effects of sensation seeking and misattribution of arousal on attraction toward similar or dissimilar strangers

While previous research has indicated that certain situational variables can mediate the typical positive relationship between attitudinal similarity and attraction, investigations focusing on the impact of individual difference variables on this relationship have typically yielded unimpressive results. The present experiment was conducted to test the prediction that individual differences in sensation seeking do moderate this relationship. The major results showed that, as predicted, high sensation seekers were more attracted than low sensation seekers to dissimilar others, whereas low sensation seekers were more attracted than high sensation seekers to people with similar attitudes. The data also indicated that a misattribution of arousal manipulation serves to increase attraction under certain conditions. Specifically, misattribution of aversive arousal increased low sensation seekers' attraction to a dissimilar stranger and increased high sensation seekers' attraction to a similar stranger.     

The Anatomy of Revolutionists

A questionnaire containing 62 items relating to the New Left and 28 items measuring anomia, authoritarianism, and Machiavellianism was given to 153 entering freshmen at Columbia in the fall of 1968. The five factors emerging from a factor analysis of responses to the items were labeled: New Left Philosophy, Revolutionary Tactics, Machiavellian Tactics, Machiavellian Cynicism, and Traditional Moralism. Students who had been politically active prior to coming to college scored higher than the rest of the group on New Left Philosophy, Revolutionary Tactics, and Machiavellian Cynicism, but scored lower on Machiavellian'Tactics and Traditional Moralism. In the spring of 1969, a revised set of items was given to students in introductory psychology classes at Columbia University and New York University. While the findings from these subjects replicated those found with the Columbia freshmen, they showed subtle differences which led to speculations about the radicalization process. Also discussed are the relationships between the nature of political participation and all of the factors, with special emphasis on the discrepancy between Machiavellian Tactics and Cynicism.     

Factors Related to Inconsistent Career Preferences

A sample of entering college freshmen was divided into 2 groups on the basis of the consistency or inconsistency of their first and second career preferences. The two groups were compared on several family and personal factors in order to identify variables that are related to inconsistencies in career preferences. The groups were observed to be somewhat different in the general level of their academic ability and the degree to which their interests were supported by SVIB results. No significant family differences between the two groups were observed. These findings were tentatively interpreted as implying that the inconsistency of career preference was more likely to be the result of the student's recognition of his limited abilities than the other variables examined in this study.     

Epinephrine facilitation of appetitive learning: attenuation with adrenergic receptor antagonists

Previous studies using aversive training tasks have reported that retention is enhanced by post-training administration of epinephrine. This study investigated the effects of post-training administration of epinephrine on retention of an appetitive task. The results indicate that epinephrine can enhance retention performance in an appetitive task of both rats and mice. Pretraining injections of propranolol and phenoxybenzamine, alpha- and beta-adrenergic receptor antagonists, attenuate the memory-enhancing effects of epinephrine. These results are consistent with the view that release of peripheral epinephrine may regulate storage of new information and may mediate memory modulation produced by a variety of treatments.     

Brain catecholamines and memory modulation: effects of footshock, amygdala implantation, and stimulation

The results of previous studies indicate that the extent of a transient decline in brain norepinephrine (NE) levels shortly after training and administration of any of several memory modulating treatments is correlated with later retention performance. The present experiment assessed such changes after one-trial inhibitory (passive) avoidance training and, in addition, measured concentration changes in 3-methoxy-4-hydroxyphenylglycol (MHPG), the major metabolite of brain NE, as well as dopamine (DA) and epinephrine (EPI) levels. The results indicate that the decreases in brain NE after footshock are accompanied by an increase in MHPG, thus providing additional evidence that brain NE is released after training. DA levels were unchanged after training; brainstem EPI levels increased after the training footshock, but forebrain EPI levels were unchanged. A second experiment examined brain catecholamine levels in animals which received post-training electrical stimulation of the amygdala. The findings of this experiment indicate that the amygdala damage which accompanies electrode implantation apparently results in a chronic change in whole brain NE levels and metabolism. After amygdala, NE concentrations in both brainstem and forebrain samples were reduced by 20% and MHPG was increased by 22-34%. Furthermore, NE levels were not responsive to training in implanted animals. Thus, brain NE levels after training were not predictive of retention performance in amygdala-implanted or -stimulated animals. However, the significance of such findings for understanding the possible role of central NE in memory storage is complicated by the severe modification of the dynamics of brain aminergic systems in animals bearing amygdala electrodes.