Inhibition of the LH Surge by Restraint Stress in Cyclic Rats: Studies on the Role of GABAA and GABAB Receptors

There is evidence that stress can alter the activity in the brain of gamma-aminobutyricacid (GABA), a neurotransmitter that has been implicated in the regulation of LH secretion. In the present study the role of GABA in the restraint stress-induced inhibition of the LH surge was investigated in the intact cyclic rat. Intracerebroventricular (icv) administration of the GABAA receptor agonist muscimol (0.1, 0.5 or 1 μg) 5 min before the presumed onset of the pro-oestrous LH surge (at 0900 h) caused a dose dependent suppression of the surge. A single dose of the GABAB receptor agonist baclofen (1 μg; icv) injected at 0855 h postponed the onset of the LH surge, and repeated injections at 0855 and 1130 h suppressed the surge. These data indicate that GABA-ergic activity in the brain can inhibit the LH surge in the cyclic rat via GABAA and GABAB receptors. Pro-oestrous rats were subjected to 5 hrs of restraint starting at 0855 h. Pretreatment with the GABAA receptor antagonist bicuculine (1 μg; icv) at 0840, 0940 and 1040 h or pretreatment with the GABAB receptor antagonist phaclofen (10 μg; icv) at 0840 h were ineffective in preventing the restraint-induced inhibition of the LH surge. The results suggest that GABAA and GABAB receptors are not involved in the inhibitory effect of restraint stress on the LH surge.     

School climate and ethnic‐racial identity in school: A longitudinal examination of reciprocal associations

The messages youth receive in schools about how they matter as individuals and as members of ethnic‐racial groups are influential in constructing their developing ethnic‐racial identities (ERI). However, the developing ERI students hold also have a role in shaping their experiences at school. The current study examined the longitudinal and reciprocal association between ERI (exploration and resolution) and school climate (support for cultural pluralism and teacher supportiveness) among 491 Black, Latino, and White middle school youth (M_age = 12.03, SD = 1.05, range: 11–17) in the Midwest. Cross‐lagged analyses revealed that greater perceptions of support for cultural pluralism within the school predicted greater exploration and resolution at later time points for all students. Moreover, greater exploration and resolution among White students was predictive of greater perceptions of support for cultural pluralism at the school. Higher quality teacher–student relationships predicted greater engagement in ERI exploration for all youth. The findings highlight the importance of school climate in helping shape ERI among youth attending a culturally diverse school and the role of such youth in shaping the climate at their school.     

Protective Factors Associated with Preadolescent Violence: Preliminary Work on a Cultural Model

This study explores the influences of communal values, empathy, violence avoidance self-efficacy beliefs, and classmates' fighting on violent behaviors among urban African American preadolescent boys and girls. As part of a larger intervention study, 644 low-income 5th grade students from 12 schools completed a baseline assessment that included the target constructs. Boys reported more violent behaviors, and lower levels of empathy and violence avoidance self-efficacy beliefs than girls. Path analyses revealed that, after controlling for the positive contributions of classmates' fighting, violence avoidance self-efficacy beliefs were a negative predictor of violent behavior. Communal values had a direct negative relationship with violence for boys, but not girls. Both communal values and empathy were associated with less violent behavior through positive relationships with violence avoidance self-efficacy beliefs. For girls, classmate fighting had an indirect positive association with violent behavior through its negative relationship with violence avoidance self-efficacy beliefs. Findings are discussed in terms of implications of basic and applied research on violence among African American youth.     

Sociopolitical development

This paper examines theories and concepts relevant to sociopolitical development (SPD). As an emerging theory, SPD expands on empowerment and similar ideas related to social change and activism in community psychology—oppression, liberation, critical consciousness, and culture among them. SPD is the process by which individuals acquire the knowledge, analytical skills, emotional faculties, and the capacity for action in political and social systems necessary to interpret and resist oppression. Equally as important is a vision of liberation that is an alternative to oppressive conditions. All of these concepts have been underemphasized in the social change literature of U.S. community psychology. In our view, sociopolitical development is vital to human development and the creation of a just society. As part of identifying and illustrating concepts and processes relevant to SPD theory, we will draw from the words of young African American activists who were interviewed as part of a research study.     

Response acquisition under targeted percentile schedules: a continuing quandary for molar models of operant behavior.

The number of responses rats made in a "run" of consecutive left-lever presses, prior to a trial-ending right-lever press, was differentiated using a targeted percentile procedure. Under the nondifferential baseline, reinforcement was provided with a probability of .33 at the end of a trial, irrespective of the run on that trial. Most of the 30 subjects made short runs under these conditions, with the mean for the group around three. A targeted percentile schedule was next used to differentiate run length around the target value of 12. The current run was reinforced if it was nearer the target than 67% of those runs in the last 24 trials that were on the same side of the target as the current run. Programming reinforcement in this way held overall reinforcement probability per trial constant at .33 while providing reinforcement differentially with respect to runs more closely approximating the target of 12. The mean run for the group under this procedure increased to approximately 10. Runs approaching the target length were acquired even though differentiated responding produced the same probability of reinforcement per trial, decreased the probability of reinforcement per response, did not increase overall reinforcement rate, and generally substantially reduced it (i.e., in only a few instances did response rate increase sufficiently to compensate for the increase in the number of responses per trial). Models of behavior predicated solely on molar reinforcement contingencies all predict that runs should remain short throughout this experiment, because such runs promote both the most frequent reinforcement and the greatest reinforcement per press. To the contrary, 29 of 30 subjects emitted runs in the vicinity of the target, driving down reinforcement rate while greatly increasing the number of presses per pellet. These results illustrate the powerful effects of local reinforcement contingencies in changing behavior, and in doing so underscore a need for more dynamic quantitative formulations of operant behavior to supplement or supplant the currently prevalent static ones.     

Middle School as a Developmental Niche for Civic Engagement

The present study investigated how school climate, school connectedness and academic efficacy beliefs inform emergent civic engagement behaviors among middle school youth of color. These associations were examined both concurrently and longitudinally using a developmentally appropriate measure of civic engagement. Data were drawn from two subsamples of a larger study of social/emotional development in middle school (cross‐sectional sample n = 324; longitudinal sample n = 232), M = 12 years old, 46 % female, 53 % male. Forty‐two percent (42.2 %) of the sample self‐identified as African American, 19.8 % as Multiracial or Mixed, 19.4 % as Latino, 11.6 % as Asian American or Pacific Islander, 11.6 % identified as Other, and 5.2 % as Native American. The study tested and found support for a latent mediation model in which more positive perceptions of school climate were positively related to school connectedness, and this in turn, was positively associated with civic engagement; school climate was also positively associated with academic‐self‐efficacy beliefs, but such beliefs did not mediate the climate‐civic engagement association. Implications for future research and practice are discussed.