Structural connectivity between the hippocampus and cortical/subcortical area relates to cognitive impairment in schizophrenia but not in mood disorders

Cognitive impairment in schizophrenia and other psychiatric disorders is a challenge to be overcome in order to maintain patients' quality of life and social function. The neurological pathogenesis of cognitive impairment requires further elucidation. In general, the hippocampus interacts between the cortical and subcortical areas for information processing and consolidation and has an important role in memory. We examined the relationship between structural connectivity of the hippocampus and cortical/subcortical areas and cognitive impairment in schizophrenia, major depressive disorder and bipolar disorder. Subjects comprised 21 healthy controls, 19 patients with schizophrenia, 20 patients with bipolar disorder and 18 patients with major depressive disorder. Diffusion-weighted tensor images data were processed using ProbtrackX2 to calculate the structural connectivity between the hippocampus and cortical/subcortical areas. Cognitive function was assessed using the Brief Assessment of Cognition in schizophrenia composite score. Hippocampal structural connectivity index was significantly correlated with composite score in the schizophrenia group but not in the healthy control, major depressive disorder or bipolar disorder groups. There were no statistically significant differences in hippocampal structural connectivity index between the four groups. Structural connectivity between the hippocampus and cortical/subcortical areas is suggested to be a pathophysiological mechanism of comprehensive cognitive impairment in schizophrenia.     

The Role of Families and Care Givers as Risk and Protective Factors in Preventing Youth Violence

This paper reviews research which discusses the risk and protective functions that families and other caregivers provide in influencing the development of aggressive behavior in youth. Currently, there is an emphasis on providing violence prevention programs in the school environment, typically with little parental or caregiver involvement. By enhancing the role of families and caregivers in youth violence prevention programs, we assert that an unique opportunity exists to both address specific risk factors for violence while enhancing the protective features of the family. Relatedly, the risk literature on youth violence indicates that the most influential risk factors (i.e., the family, community, and peers) have their principle impact on youth aggression outside the school. We suggest a shift in the focus of violence prevention programming that is more inclusive of families as both a risk and protective agent. In support of this position, relevant theory and reviews of exemplary family-involved programs are offered. Challenges to involving youth caregivers are identified and recommendations for overcoming those challenges suggested. Last, recommendations for future research and public policy in the prevention of youth violence are offered.     

A variable that may affect individual differences in the child-directed speech of Japanese women

Sixty-one single Japanese-speaking women between the ages of 18 and 26 years were recorded as they read aloud picture books to a young child and as they conversed with another Japanese-speaking woman. When their utterances were acoustically compared between the two settings with regard to prosodic features, both the average pitch and pitch excursions exhibited a significant increase when interacting with the child in 17 of the 61 women. In 36 of the remaining 44 subjects, neither of these parameters showed such changes. This individual variability was not related to the subjects' liking for picture books, previous experience with reading or being read them, or with baby-sitting. The only variable that could explain the results was whether the subjects had grown up with one or more siblings or as only children. If they were only children, the prosodic modification was significantly less likely to occur     

Effects of self-efficacy on adjustment to college

This study examined the effects of self-efficacy on adjustment to college among 1385 Japanese college students. The College Adjustment Self-Efficacy Scale (CASES) was constructed in order to evaluate the degree of confidence in the skills necessary for college adjustment. Three subscales were identified in the CASES: judgmental ability based on objective information, self-controlled persistence of activity, and self-adjustment in human relations. There were slight gender differences in the first and the third subscales. The CASES subscale scores were compared between well and poorly adjusted students in each college major. Differences in the score patterns of well adjusted students were compared across 13 college majors. The implications for academic career counseling are discussed.     

Effects of peripheral immune activation on social behavior and adrenocortical activity in aggressive mice: Genotype-environment interactions

To explore genetic-developmental differences in the biobehavioral effects of induced illness, males from two lines of mice selectively bred for high or low levels of aggressive behavior were injected with endotoxin (Escherichia coli, LPS: 0.25 mg/kg, 1.25 mg/kg, or 2.5 mg, i.p.) or saline. Body temperature, weight, and locomotor activity were monitored immediately before and 8 and 24 hr after injection. Twenty-four hours after injection, social behaviors were assessed in a 10-min dyadic test, and hypothalamus, spleen, and serum were collected. In both lines, endotoxin treatment increased behavioral immobility ("freezing") and decreased social exploration. Other effects showed line differences: Males from the high-aggressive line had a lower threshold to endotoxin-induced effects on body temperature, weight loss, spleen weight, and corticosterone. Social reactivity (startle response to mild social investigation) increased in the high-aggressive line and decreased in the low-aggressive line after treatment. In the high-aggressive line only, endotoxin decreased attack frequency and increased latency to attack. The interactions between selected line (genotype) and endotoxin treatment (environment) demonstrate that genetic-developmental differences in social and aggressive behavior may indicate the extent to which immune stimuli (e.g., bacteria, viruses, cytokines) function as "biobehavioral stressors." Aggr. Behav. 23:93–105, 1997.© 1997 Wiley-Liss, Inc.     

THE UTILITY OF CURRICULUM-BASED MEASUREMENT FOR EVALUATING THE EFFECTS OF METHYLPHENIDATE ON ACADEMIC PERFORMANCE

Two case studies were conducted to investigate the utility of curriculum-based measurement of math and reading for evaluating the effects of methylphenidate on the academic performance of 2 students diagnosed with attention deficit hyperactivity disorder. Following baseline measurement, double-blind placebo-controlled procedures were employed to evaluate each student's response to three levels (5 mg, 10 mg, and 15 mg) of the medication. Results of the first study suggest that the curriculum-based measures were sensitive indicators of the student's response to medication. This finding was replicated in the second study. In the second study, when the student's follow-up dose of medication was based on trial-phase data, follow-up performance was improved compared to baseline performance. These case studies suggest that further research is warranted on the utility of curriculum-based measurements for monitoring and evaluating stimulant medication interventions with children with this disorder.     

Useful visual field size for pattern perception

The useful visual field size at each fixation in a pattern was investigated by artificially supplying various visual field sizes on a TV display. The degree of pattern perception was measured in terms of recognition memory for pictures, and the speed of processing pictures was determined as a function of field size. A serious deterioration in the perception of pictures occurred as the visual field was limited to a small area around the fovea (about 3.3° × 3.3°), processing speed becoming extremely slow. Speed increased gradually as visual field size became larger, to reach a certain level beyond which no further increase was observed. The visual field size at this asymptotic speed was called the useful visual field and was found to be about 50% of the entire pattern size. Analysis of eye-movement records demonstrated that in terms of the useful visual field, the scanning characteristics of the eye over the pattern occurred in a heavily overlapping manner to assure good perception of the pattern.     

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.     

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.     

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.