Genetic background differences and nonassociative effects in mouse trace fear conditioning

Fear conditioning, including variants such as delay and trace conditioning that depend on different neural systems, is widely used to behaviorally characterize genetically altered mice. We present data from three strains of mice, C57/BL6 (C57), 129/SvlmJ (129), and a hybrid strain of the two (F(1) hybrids), trained on various versions of a trace fear-conditioning protocol. The initial version was taken from the literature but included unpaired control groups to assess nonassociative effects on test performance. We observed high levels of nonassociative freezing in both contextual and cued test conditions. In particular, nonassociative freezing in unpaired control groups was equivalent to freezing shown by paired groups in the tests for trace conditioning. A number of pilot studies resulted in a new protocol that yielded strong context conditioning and low levels of nonassociative freezing in all mouse strains. During the trace-CS test in this protocol, freezing in unpaired controls remained low in all strains, and both the C57s and F(1) hybrids showed reliable associative trace fear conditioning. Trace conditioning, however, was not obtained in the 129 mice. Our findings indicate that caution is warranted in interpreting mouse fear-conditioning studies that lack control conditions to address nonassociative effects. They also reveal a final set of parameters that are important for minimizing such nonassociative effects and demonstrate strain differences across performance in mouse contextual and trace fear conditioning.     

Reactions to and Desire for Prognostic Testing in Choroidal Melanoma Patients

To determine if choroidal melanoma patients want cytogenetic prognostic information. Ninety-nine choroidal melanoma patients completed a questionnaire regarding their opinions about receiving prognostic information. The perceived usefulness of prognostic information was evaluated in patients who had undergone cytogenetic testing. Depressive symptoms, quality of life, and interest in supportive counseling during test receipt were assessed. Ninety-seven percent of respondents reported that they would have wanted prognostic information at the time of their treatment and 98% of respondents reported that supportive counseling should be offered when prognostic information is given. Patients who had received a more favorable prognostic result were more likely to endorse the usefulness of cytogenetic testing than were patients who had received a less favorable prognostic result. Psychological status did not vary significantly as a function of cytogenetic test result. Prognostic information was important to patients with choroidal melanoma, even in the absence of prophylactic measures which might improve prognosis.     

The parental attitude research instrument: An approach to use of attitude questionnaires

Parental attitude questionnaires such as the Parental Attitude Research Instrument (PARI) are still in use despite their inherent difficulties. In light of the need to test theoretical models by measuring a range of parental characteristics, the properties of the PARI were re-examined and, on the basis of a factor analysis of the 23 subtests of the PARI, a shortened version was constructed. A measure of maternal Authoritarian Control, which was found to be associated with measures of maternal mental ability, personality, level of education, reading age, number of adverse family conditions and child-rearing practices, has proved useful for other projects related to this ongoing study. It is recommended that such instruments be used only in conjunction with other measures which examine the family environment, for example in an index of child-rearing practices.     

Effects of scopolamine on repeated acquisition of radial-arm maze performance by rats.

Rats repeatedly acquired the performance of selecting only the four baited arms in an automated eight-arm radial maze, with the arms containing food pellets randomly assigned prior to each session. During each 14-trial (trial: obtain all four pellets) daily session, the number of errors (selecting nonbaited arms or repeating arm selections) showed a within-session decline, and choice accuracy for the first four arm selections showed a positive acceleration across trials for all rats. An index-of-curvature statistic, calculated for total errors, was used to quantify both the within- and between-session improvement of performance. Scopolamine (0.03 to 0.3 mg/kg, ip), but not methylscopolamine (0.3 mg/kg), reduced the accuracy of the first four selections of each trial and increased total within-session errors for all rats. Session times also were increased by scopolamine. An examination of within-session accuracy showed only slight signs of improvement at the higher dosages of scopolamine. The results indicate that behavior in transition states maintained by reinforcement contingencies in the radial maze is similar to that maintained by extended chained schedules, despite the fact that some of the stimuli controlling behavior in the maze are absent at the moment behavior is emitted.     

Acute neuropsychological consequences of coronary artery bypass surgery

This study examines a series of coronary artery bypass patients (CABS) for neuropsychological and regional cerebral blood flow (RCBF) changes at 8 days and 8 weeks post surgery. Seventy-three percent were found to have moderate or severe neuropsychological deficits at 8 days post operation and 37% at 8 weeks post surgery. A comparison group of major vascular and thoracic surgery patients was also found to have a significant proportion of neuropsychological deficit following surgery. The RCBF assessments indicated a significant drop in mean RCBF at 8 days post surgery in the coronary artery bypass group which did not persist to 8 weeks. The comparison group showed no changes in RCBF following surgery. The findings suggest different patterns of recovery and origins of the neuropsychological deficit in the two groups and emphasize the need for appropriate control groups in studies examining the cortical effects of extracorporeal circulation. In addition, the project received generous support from the special trustees of the Middlesex Hospital.     

Autoshaped key pecking maintained by access to a social space.

When four experimentally naive pigeons were exposed to occasional forward pairings of a keylight followed by a doorlight (that signaled access to a large social space), all subjects began to peck the lit key. In a second experiment, where the keylight either preceded the presentation of the doorlight or was presented independently of it, key pecking was maintained only in the former circumstance. The unconditioned stimulus in these experiments--arrival in the social space--did not elicit pecking. Hence, the conditioned response of key pecking and the unconditioned response of entering the social space differed. This demonstration of autoshaping with a social-space unconditioned stimulus argues against a stimulus-substitution account of the findings.     

Perceptions of parent-adolescent communication within families: it is a matter of perspective

This study examined the concordance between parental and youth's perceptions regarding open communication in their families and its association with youth's psychosocial adjustment. The relative importance of parental and adolescents' perceptions of open family communication in relation to youth's psychosocial adjustment was also investigated. Participants were 336 parent-youth dyads from inner-city low-income communities in an eastern city in the United States. Both parental and youth's perceptions of open communication in the family were categorized into "high" and "low" groups using a median split in scores. Four parent-youth concordance groups (i.e. high-high, high-low, low-high and low-low) were derived based on the combination of the levels of parental and youth's perceptions. Parental and youth's perceptions about open communication were modestly correlated (r = 0.129, p < 0.05). The level of concordance differed by youth gender with male adolescents and their parents being more likely to perceive lower levels of open communication (i.e. "low-low") than females and their parents (32% versus 19%, p < 0.05). In general, youth demonstrated poorer psychosocial adjustment if they perceived a lower level of open communication between them and their parents, independent of the level of their parents' perceptions (e.g. "high" or "low"). The findings suggest an important role of adolescents' own perceptions of the openness of the family communication in relation to adolescent psychosocial adjustment. Developmentally and gender appropriate intervention programs are needed to improve the openness of parent-adolescent communication, to help both parents and youth to recognize the significant preventive role of open communication in the family, especially, the socioeconomically disadvantaged families.     

Gender biases in children's appraisals of injury risk and other children's risk-taking behaviors

Children ages 6, 8, and 10 years were given tasks designed to assess their beliefs about risk of injury from activities. Children were asked to appraise the risk of injury for boys and girls engaging in various play behaviors and to judge the sex of the character in stories about children engaging in activities that result in injuries. Results revealed gender biases in children's appraisals of injury risk: Both boys and girls rated boys as having a lower likelihood of injury than girls even though the boys and girls were engaging in the exact same activities. Children also showed higher accuracy in identifying the sex of the character in stories of boys' injuries than girls' injuries, and accuracy improved with the participant's age. Overall, the results indicate that by the age of 6 years children already have differential beliefs about injury vulnerability for boys and girls. Although boys routinely experience more injuries than girls, children rate girls as having a greater risk of injury than boys. With increasing age, school-age children develop a greater awareness of the ways in which boys and girls differ in risk-taking activities that lead to injury outcomes.