MAP2 and synaptophysin protein expression following motor learning suggests dynamic regulation and distinct alterations coinciding with synaptogenesis

Learning a new motor skill can induce neuronal plasticity in rats. Within motor cortex, learning-induced plasticity includes dendritic reorganization, synaptogenesis, and changes in synapse morphology. Behavioral studies have demonstrated that learning requires protein synthesis. It is likely that some of the proteins synthesized during learning are involved in, or the result of, learning-induced structural plasticity. We predicted the expression of proteins involved in neural plasticity would be altered in a learning dependent fashion. Long-Evans rats were trained on a series of motor tasks that varied in complexity, so that the effects of activity could be teased apart from the effects of learning. The motor cortices were examined for MAP2 and synaptophysin protein using Western blotting and immunohistochemistry. Western blotting revealed that expression of MAP2 was not detectably influenced by learning, whereas synaptophysin expression increased on day 1, 3, and 5 of complex motor skill learning. Expression of MAP2 does not seem to indicate difficulty of task or duration of training time, whereas increases in synaptophysin expression, which appear diffusely across the cortex, seem to be correlated with the first 5 days of motor skill learning. Similar findings with GAP-43 suggest the change in synaptophysin may coincide with synapse formation. Immunohistochemistry did not reveal any localized changes in protein expression. These data indicate a difference in learning-induced expression in the mammalian brain compared to reports in the literature, which have often focused on stimulation to induce alterations in protein expression.     

The relationship of offending style to psychological and social risk factors in a sample of adolescent males

Research has indicated that life‐course persistent offenders typically vary their offending style, following a criminal career progression from co‐ to solo‐offending. Few studies have investigated the offenders who contemporaneously mix their style of offending. A sample of 1,047 male adolescent offenders from the Pathways to Desistance study was investigated over a 7‐year period. Participants were identified as solo, co or contemporaneous mixed style (CMS) offenders for each wave of data and one‐way between groups analysis of variance was conducted to examine variations between the different offending styles in terms of offending frequencies, exposure to violence, peer antisocial behaviour and influence, resistance to peer influence, impulse control and psychopathy. CMS offenders were found to consistently report significantly higher rates of offending and present significantly higher negative risk factors and lower protective risk factors than solo‐ and co‐offenders for the duration of the study. A multinomial logistic regression was used to investigate predictors of offending style with CMS as the reference category. Higher levels of exposure to violence and peer antisocial behaviour and lower levels of impulse control predicted membership of the CMS group for the first part of the study when compared with co‐offenders; and higher levels of exposure to violence and peer antisocial behaviour continued to predict CMS offending when compared to solo‐offenders until the end of the study.     

Differential Effects of Ecstasy on Short-Term and Working Memory: A Meta-Analysis

Quantitative analysis of studies examining the effect of ecstasy on short-term and working memory in the verbal and visuo-spatial domain was undertaken. Thirty verbal short-term memory, 22 verbal working memory, 12 visuospatial short-term memory and 9 visuospatial working memory studies met inclusion criteria. Ecstasy users performed significantly worse in all memory domains, both in studies using drug-naïve controls and studies using polydrug controls. These results are consistent with previous meta-analytic findings that ecstasy use is associated with impaired short-term memory function. Lifetime ecstasy consumption predicted effect size in working memory but not in short-term memory. The current meta-analysis adds to the literature by showing that ecstasy use in humans is also associated with impaired working memory, and that this impairment is related to total lifetime ecstasy consumption. These findings highlight the long-term, cumulative behavioral consequences associated with ecstasy use in humans.     

A Comparison of Firefighters and Police Officers: The Influence of Gender and Relationship Status

Differences between fire department and police department personnel (N = 190) concerning work‐related stressors and depression were examined with regard to gender and relationship status. Participants completed the Beck Depression Inventory—II (A. T. Beck, R. A. Steer, & G. K. Brown, 1996) and the Distressing Event Questionnaire (E. S. Kubany, M. B. Leisen, A. S. Kaplan, & M. P. Kelly, 2000). Recommendations are made concerning what crisis theories, both traditional and nontraditional, counselors should be aware of, as well as how simply working with trauma survivors can be traumatizing. E. Erikson's psychosocial stages (as cited in J. R. Studer, 2007) are considered in the framework of adult development.     

Mug shot exposure prior to lineup identification: interference, transference, and commitment effects.

The effects of viewing mug shots on subsequent identification performance are as yet unclear. Two experiments used a live staged-crime paradigm to determine if interpolated eyewitness exposure to mug shots caused interference, unconscious transference, or commitment effects influencing subsequent lineup accuracy. Experiment 1 (N = 104) tested interference effects. Similar correct decision rates were obtained for the mug shot and no mug shot groups from both perpetrator-present and absent lineups. Experiment 2 (N = 132) tested for commitment and transference effects. Results showed that the commitment group made significantly more incorrect identifications than either the control or the transference group, which had similar false-identification rates. Commitment effects present a serious threat to identification accuracy from lineups following mug shot searches.