Susceptibility to induction of long-term depression is associated with impaired memory in aged Fischer 344 rats

The current study employed aged and young male Fischer 344 rats to examine the relationship between long-term depression (LTD), age, and memory. Memory performance was measured on two tasks that are sensitive to hippocampal function; inhibitory avoidance and spatial discrimination on the Morris water maze. The slope of the extracellular excitatory postsynaptic field potential was recorded from CA3-CA1 synapses in hippocampal slices. Low frequency stimulation (LFS) induced a modest LTD only in aged animals under standard recording conditions. The decrease in synaptic transmission examined only in aged animals correlated with memory scores on the spatial task and LTD was not observed in aged animals with the highest memory scores. LTD induction was facilitated by increasing the Ca(2+)/Mg(2+) ratio of the recording medium or employing a paired-pulse stimulation paradigm. Age differences disappeared when LFS was delivered under conditions of elevated Ca(2+)/Mg(2+) in the recording medium. Using multiple induction episodes under conditions which facilitate LTD-induction, no age-related difference was observed in the maximum level of LTD. The results indicate that the increased susceptibility to LTD induction is associated with impaired memory and results from a shift in the induction process. The possible relationship between LTD and memory function is discussed.     

The Beliefs in the Inheritance of Risk Factors for Suicide Scale (BIRFSS): Cross‐Cultural Validation in Estonia,Malaysia, Romania,the United Kingdom,and the United States

The genetics of suicide is increasingly recognized and relevant for mental health literacy, but actual beliefs may lag behind current knowledge. We examined such beliefs in student samples (total N = 686) from Estonia, Malaysia, Romania, the United Kingdom, and the United States with the Beliefs in the Inheritance of Risk Factors for Suicide Scale. Cultural effects were small, those of key demographics nil. Several facets of construct validity were demonstrated. Marked differences in perceived plausibility of evidence about the genetics of suicide according to research design, observed in all samples, may be of general interest for investigating lay theories of abnormal behavior and communicating behavioral and psychiatric genetic research findings.     

Psychiatric sequelae of low birth weight at 6 years of age

The study examined the association between low birth weight (LBW) (2,500 g) and attention deficit hyperactivity disorder (ADHD) in two socioeconomically disparate populations. LBW and normal birth weight (NBW) children from the 1983 to 1985 newborn lists of an urban and a suburban hospital in Southeast Michigan were randomly selected. A total of 823 children, 473 LBW and 350 NBW, participated. Data were gathered in 1990 to 1992, when the children were 6 to 7 years of age. The National Institute of Mental Health Diagnostic Interview Schedule for children—Parent version (DISC-P) was used to elicit information on DSM-III-R diagnoses of simple phobia, overanxious, separation anxiety, oppositional defiant, and ADHD. Teachers' ratings of behavior problems were obtained. LBW was associated with ADHD but not with childhood anxiety disorders or oppositional defiant disorder. The association was stronger in the urban than in the suburban population. Data from teachers' ratings revealed an association between LBW and attention problems. The prognostic significance of the observed psychopathology at 6 years of age requires follow-up assessment as the children mature.This research was supported by NIMH research grant MH-44586 and NIMH Research Scientist Development Award MH-00380 to Dr. Breslau.     

Should One be Free to Choose the Sex of One's Child?

ABSTRACT Tests which predict the sex of a fetus have led to female feticide in India, and hence to demands that such tests be banned. This paper examines the arguments for banning such tests. These will depend partly on one's views regarding the morality of feticide: different views are discussed. However the morality of feticide is not the only relevant consideration, especially since it may become possible to choose the sex of the child at conception. Whether or not parents have the right to freedom of choice and information is analysed. Many non-western societies have special problems since the strong preference for boys may lead to the neglect of female children and to female infanticide. In heavily populated countries like India and China the need to control population growth is an additional complication. The paper concludes that in these societies the case for banning tests is weak.     

“Leave Your Comment Below”: Can Biased Online Comments Influence Our Own Prejudicial Attitudes and Behaviors?

Increased use of online communication in everyday life presents a growing need to understand how people are influenced by others in such settings. In this study, online comments established social norms that directly influenced readers' expressions of prejudice both consciously and unconsciously. Participants read an online article and were then exposed to antiprejudiced or prejudiced comments allegedly posted by other users. Results revealed that exposure to prejudiced (relative to antiprejudiced) comments influenced respondents to post more prejudiced comments themselves. In addition, these effects generalized to participants' unconscious and conscious attitudes toward the target group once offline. These findings suggest that simple exposure to social information can impact our attitudes and behavior, suggesting potential avenues for social change in online environments.     

Risking Future Generations

Many of the policy choices we face that have implications for the lives of future generations involve creating a risk that they will live lives that are significantly compromised. I argue that we can fruitfully make use of the resources of Scanlon’s contractualist account of moral reasoning to make sense of the intuitive idea that, in many cases, the objection to adopting a policy that puts the interest of future generations at risk is that doing so wrongs those who will live in the further future.     

Average group behavior does not represent individual behavior in classical conditioning of the honeybee

Conditioned behavior as observed during classical conditioning in a group of identically treated animals provides insights into the physiological process of learning and memory formation. However, several studies in vertebrates found a remarkable difference between the group-average behavioral performance and the behavioral characteristics of individual animals. Here, we analyzed a large number of data (1640 animals) on olfactory conditioning in the honeybee (Apis mellifera). The data acquired during absolute and differential classical conditioning differed with respect to the number of conditioning trials, the conditioned odors, the intertrial intervals, and the time of retention tests. We further investigated data in which animals were tested for spontaneous recovery from extinction. In all data sets we found that the gradually increasing group-average learning curve did not adequately represent the behavior of individual animals. Individual behavior was characterized by a rapid and stable acquisition of the conditioned response (CR), as well as by a rapid and stable cessation of the CR following unrewarded stimuli. In addition, we present and evaluate different model hypotheses on how honeybees form associations during classical conditioning by implementing a gradual learning process on the one hand and an all-or-none learning process on the other hand. In summary, our findings advise that individual behavior should be recognized as a meaningful predictor for the internal state of a honeybee--irrespective of the group-average behavioral performance.     

Suicidal behavior in hospitalized schizophrenics

A group of 131 hospitalized schizophrenics who had attempted suicide within the past year was compared with another group of 70 hospitalized schizophrenics who had not attempted suicide, using the Present State Examination (PSE) depressive symptoms. The former had a significantly higher number of symptoms indicative of a depressive disorder.