Contextual learning induces an increase in the number of hippocampal CA1 neurons expressing high levels of BDNF

We examined behaviorally induced expression of brain-derived neurotrophic factor (BDNF) in area CA1 of the hippocampus. Sprague-Dawley rats were trained in a contextual fear conditioning (CFC) task, sacrificed 4h later, and their brains were processed for immunohistochemistry. We found distinctively high levels of BDNF immunoreactivity in a small number ( approximately 1%) of CA1 neurons in untrained animals. The number of these exceptional neurons, which are identified as BDNF(++) in this study, was increased by up to approximately 3% after CFC. This increase was blocked in the presence of a memory-impairing dose of a NMDA receptor antagonist (MK801 0.3 mg/kg, i.p.) given 30 min prior to training. The BDNF signal intensity in BDNF(++) neurons correlated with that of surrounding glutamic acid decarboxylase (GAD) 65. This correlation between GAD65 and BDNF signal intensities suggests that BDNF upregulation was associated with increased signaling via inhibitory GABAergic synapses that would lessen further intervening neuronal activity. Our observation that neurons which upregulate BDNF expression following a learning experience are rich in GAD65-enriched afferent synapses suggests that these neurons may have distinct roles in memory consolidation.     

Optimistic and pessimistic biases and comparative judgmental processes in Japan: Do people really compare themselves to their peers?

Studies on above-average and unrealistic-optimism effects have recently claimed that they are the consequence of an over-utilization of self-relevant and under-utilization of peer-relevant information, despite the assumption that people would refer to both themselves and their average peer to make a comparative judgment. However, there is a possibility that these tendencies are prevalent only in Western cultures. The present paper reports on three studies of comparative self-other judgments conducted with Japanese university students. The results consistently showed that participants tended to focus simply on their own abilities, traits, or the likelihood of experiencing future life events, without paying much attention to their peers. These findings suggest first that there is a consistent tendency for people to place a greater weight on the self than normative standards when considering their comparative position in a group, and that this tendency is independent of the size or direction of comparative biases.     

Color‐specific filtering of rival binocular inputs induced by priming1

Abstract: In a situation where the two eyes separately receive two dissimilar images such as a blue square and a red square, the brain is forced to resolve competitive interpretations of the visual inputs. Earlier studies have indicated that adaptation to one of two rival images can control the following competitive perception. Consistent with those studies, the present experiments revealed that immediately after a brief presentation of a color (priming stimulation) to the two eyes, subjects dominantly perceived the other color out of the chromatic rivalry. This effect showed an interocular transfer even if indirect monocular priming was employed, but the filtering out of a primed color did not occur when an unprimed rival image was removed from the other eye. These facts suggest that binocular feature‐detection processes in the human visual system might be responsible for the priming effect on rival images.     

Residential mobility increases motivation to expand social network: But why?

We conducted two studies to explore psychological consequences of a mobile lifestyle. In Study 1, we found that participants who were randomly assigned to think about a mobile lifestyle used more loneliness and sadness-related words and anticipated having fewer friends in the future than those who thought about a stable lifestyle (or a typical day as a control). In Study 2, we replicated this finding with a non-college sample. In addition, we found that those in the mobility condition reported being more motivated to expand their social network. Finally, the effect of mobility on the motivation to expand social networks was mediated by anticipated loneliness and sadness.     

Age-related trends of interference control in school-age children and young adults in the Stroop color-word test

In this cross-sectional study, differences in interference control, one component of executive function, were investigated among three age groups, 15 early childhood (7- to 8-yr.-olds), 25 middle childhood (9- to 12-yr.-olds), and 20 young adults (21- to 30-yr.-olds). Participants were administered a computer version of the Stroop color-word test with an oral response; correct responses, response time (RT), and the interference ratio were examined. The data indicated that (1) most of the participants showed no errors in word reading, color-naming, and incongruent color-naming tasks; (2) in word-reading and color-naming tasks, RT for 7- to 8-yr.-olds was longer than that for 9- to 12-yr.-olds, while RT of 9- to 12-yr.-olds and young adults were comparable; (3) in an incongruent color-naming task, RT for 7- to 8-yr.-olds was longer than RT for 9- to 12-yr.-olds, which was longer than RT for young adults; and (4) the interference ratio was higher in 7- to 8-yr.-olds than in 9- to 12-yr.-olds, which was higher than in young adults. These results suggested the difference in interference control between early and middle childhood reported on the go/no-go task and the stop-signal procedure would be observed in the Stroop color-word paradigm as well. The utility of this modified Stroop color-word test for those with intellectual and developmental disabilities was discussed.     

Adolescent problem behavior: The effect of peers and the moderating role of father absence and the mother-child relationship

Examined the effect of peer problem behavior, the absence of a father or equivalent in the home, and the mother-adolescent relationship as predictors of adolescent problem behavior in a sample of 112 African American adolescents. Statistical analyses compared a moderator model to a mediational model and a cumulative risk model. As predicted, the moderator model was superior to the alternative models. Specifically, whereas the mediational model predicted that the effect of father absence and the mother-child relationship upon adolescent problem behavior would be mediated by peer problem behavior, neither effected peer problem behavior or adolescent problem behavior. Similarly, a cumulative risk index did not predict either child or parent reports of problem behavior and was not sensitive to specific contingencies that existed between the predictor variables. In contrast, an interactive, moderator model described the data quite well. This model suggested that father or equivalent absence magnifies the negative impact of peer problem behavior, while a positive mother-adolescent relationship attenuates this risk. A strong mother-adolescent relationship also served to protect adolescents in father-absent homes from the risk of peer problem behavior. This research was supported by a grant (NICHHD: HD24056) awarded to A. M. Cauce. The authors thank Nydia Ordonez, Tanya Aguilar, and Laurie Deppman for their assistance on the project, and Cliff Lunneberg for suggestions regarding resampling procedures. Portions of this paper were presented at the meetings of the Western Psychological Association, April 1992.     

Digit memory of soroban experts: Evidence of utilization of mental imagery

Two experiments were conducted to demonstrate that skilled soroban (Japanese abacus) operators can improve digit memory retention by manipulating the beads of a ‘mental soroban’ which is analogous to the actual one. In Experiment 1, soroban experts and control subjects were given two digit memory tasks. In one task, pictures of a soroban figure and in the other, pictures of digit sequences, were presented to the subjects during the retention interval. Soroban experts experienced greater interference from presentation of the soroban figures than the digits; on the other hand, the reverse was true in the control subjects. In Experiment 2, ther soroban experts and control subjects were given the same digit memory tasks under three conditions—soroban pictures, pictures of digit sequences, and human faces were presented to subjects during the retention period of 15 s. The soroban experts were more affected by the presentation of the soroban figures than by the faces or digits, whereas the controls showed more interference from the digits than by the presentation of faces or soroban pictures.     

Hostility disturbs learning

Many studies have shown that there is a strong correlation between hostility and coronary artery disease; however, the pathogenic mechanisms by which hostility causes coronary artery disease have not been identified. Several studies have shown that hostility is associated with increased cardiovascular reactivity to mental stress. Sloan and colleagues used mental arithmetic and the Stroop Color-Word Task as psychological stressors and suggested that hostility is associated with diminished cardiac vagal control. It is supposed that the diminished cardiac vagal control results in uncontrollability of increased heart rate under stressful conditions so performance on mental stress tasks is poor. However, performance was not analyzed on the Stroop Color-Word Task. If hostility influences the autonomic nervous system, the performance of this mental stress task may also differ according to extent of hostility. In the present study, whether hostility disturbed performance of a mental stress task and the practice on it was examined. Subjects completed the Cook-Medley Hostility Scale and were divided into three groups (High, Middle, and Low) by their total scores and three subscales (Cynicism, Hostile Affect, and Aggressive Responding). They also completed the Stroop Color-Word Task. Analysis showed practice by High and Middle scoring groups on Aggressive Responding had a significantly smaller effect than that by Low scoring groups. The pathogenic mechanisms by which hostility may underlie coronary artery disease were discussed.     

Does Traditional Stereotyping of Career as Male Affect College Women’s,but Not College Men’s,Career Decision Self-Efficacy and Ultimately Their Career Adaptability?

Sex Roles - In South Korea, strong beliefs about traditional gender roles in accordance with Confucian and patriarchic atmosphere still strongly influence daily life and the career development...