Role of matrix metalloproteinases in the acquisition and reconsolidation of cocaine-induced conditioned place preference

Persistent drug seeking/taking behavior involves the consolidation of memory. With each drug use, the memory may be reactivated and reconsolidated to maintain the original memory. During reactivation, the memory may become labile and susceptible to disruption; thus, molecules involved in plasticity should influence acquisition and/or reconsolidation. Recently, matrix metalloproteinases (MMPs) have been shown to influence neuronal plasticity, presumably by their regulation of extracellular matrix (ECM) molecules involved in synaptic reorganization during learning. We hypothesized that inhibition of MMP activity would impair the acquisition and/or reconsolidation of cocaine-conditioned place preference (CPP) in rats. Intracerebral ventricular (i.c.v.) microinjection of a broad spectrum MMP inhibitor, FN-439, prior to cocaine training suppressed acquisition of CPP and attenuated cocaine-primed reinstatement in extinguished animals. In a separate experiment, the cocaine memory was reactivated on two consecutive days with a cocaine priming injection. On these two days, artificial cerebral spinal fluid (aCSF) or FN-439 was administered either 30 min prior to or 1 min after cocaine-primed reinstatement sessions. Infusion of FN-439 partially impaired retrieval of the cocaine-associated context when given 30 min prior to cocaine. In both groups, however, FN-439 suppressed reinstatement compared with controls on the third consecutive test for cocaine-primed reinstatement, when no FN-439 was given. Control experiments demonstrated that two injections of FN-439 + cocaine given in the home cage, or of FN-439 + saline priming injections in the CPP chambers did not disrupt subsequent cocaine-primed reinstatement. These results show for the first time that (1) MMPs play a critical role in acquisition and reconsolidation of cocaine-induced CPP, and (2) rats demonstrate apparent disruption of reconsolidation by an MMP inhibitor after extinction and while they are under the influence of cocaine during reinstatement.     

To Be or Not to Be: Exploring the Nature of Positively and Negatively Keyed Personality Items in High-Stakes Testing

Including equal numbers of positively and negatively keyed items is common in Five-Factor Model (FFM) personality measures. Much literature has demonstrated the presence of positive and negative keying factors in low-stakes testing situations, but there is a dearth of research investigating these factors in high-stakes testing. To address this gap, we investigated whether an FFM measure used in high-stakes testing was influenced by positive and negative keying factors. We also examined the overlap of the positive and negative keying factors with social desirability, rule-consciousness, acquiescence, and cognitive ability. Confirmatory factor analysis supported the inclusion of distinct factors associated with positively and negatively keyed items and suggested that the keying factors accounted for a substantial portion of variation in responses to FFM items. Social desirability and rule-consciousness were found to have significant relations with both keying factors, whereas acquiescence was only related to the negative keying factor. Implications for the construct validity of FFM measures used in high-stakes testing and directions for future research are discussed.     

Female Body Image as a Function of Themes in Rap Music Videos: A Content Analysis

A content analysis of rap music videos taken from the end of year countdowns aired on U.S. cable outlets (i.e. BET, MTV, and VH1) was undertaken. The analysis examined the body images of 258 female characters (87.6% Black, 5.8% White, 6.6% other) as a function of the thematic content in the videos (e.g., violence, sex). It was found that, overall, “thin” females were overrepresented in the videos. More interestingly, the body sizes of the female characters varied by three of the four video themes. When the music videos were high in sex, or high in materialism, women were more likely to have smaller body sizes. In contrast, when the videos were high in political awareness, women were more likely to have larger body sizes.     

Raphael Meldola and the Nineteenth-Century Neo-Darwinians

Raphael Meldola (1849–1915), an industrial chemist and keen naturalist, under the influence of Darwin, brought new German studies on evolution by natural selection that appeared in the 1870s to the attention of the British scientific community. Meldola’s special interest was in mimicry among butterflies; through this he became a prominent neo-Darwinian. His wide-ranging achievements in science led to appointments as president of important professional scientific societies, and of a local club of like-minded amateurs, particularly field naturalists. This is an account of Meldola’s early scientific connections and studies related to entomology and natural selection, his contributions to the study of mimicry, and his promotion in the mid-1890s of a more theory driven approach among entomologists.     

The Effect of Mindfulness-based Programs on Cognitive Function in Adults: A Systematic Review and Meta-analysis

Neuropsychology Review - Mindfulness-based programs (MBPs) are increasingly utilized to improve mental health. Interest in the putative effects of MBPs on cognitive function is also growing. This...     

Social preferences of developing guinea pigs (Cavia porcellus) from the preweaning to the periadolescent periods

Preference tests in a novel environment (Experiment 1) and unobtrusive observations in a specialized living environment (Experiment 2) examined the attractiveness of various classes of conspecifics for maturing guinea pigs (Cavia porcellus). It was found that (a). the young continued to remain near the mother well beyond weaning; (b). there was increased time spent with unrelated adult females, but not males, after weaning; (c). male and female offspring behaved similarly; and (d). littermates spent considerable time with each other. These results provide no evidence that guinea pigs approaching sexual maturity begin to associate preferentially with novel animals or potential breeding partners. Choices were largely predictable from earlier findings of the ability of various classes of conspecifics to reduce hypothalamic-pituitary-adrenal activity of the young.     

When to Preach About Poverty: How Location,Race, and Ideology Shape White Evangelical Sermons

Social scientists have long been interested in how intergroup contact or elite messaging can reduce or eliminate racial biases. To better understand the role of religious elites in these political questions, we show how a church location's income and racial characteristics interact with racial and economic ideologies to shape the political content of sermons. Testing our theories through both quantitative and qualitative analysis of an original data set of more than 102,000 sermons from more than 5200 pastors, we show that contact is only effective as a means of decreasing prejudice to the extent that actors—in our case, pastors—are ideologically capable of reconciling their potential role in economic inequality. White Evangelical pastors rarely preach about issues of poverty or racial justice overall, but the context of the preaching matters. We find that the greater the share of Black population there is in a church community, the less likely White Evangelical pastors are to mention issues of poverty or racial justice, and when they do mention it, they hold to ideological commitments that avoid blaming systems for racialized economic inequality.     

Sex comparisons on causal attributions: Another look at the null hypothesis

Eighty-two subjects (49 women, 33 men) solved a difficult or easy set of anagrams, after which they indicated their subjective level of performance, provided causal attributions, and stated expectations for future performance. Sex comparisons were conducted on each element in the attribution model. Results indicated no sex differences on subjective evaluation of success, on causal dimensions, on expectations for future performance, or on performance on a final set of anagrams.