Gonadal hormones and intrasexual aggressive behavior in female bank voles (Clethrionomys glareolus)

The effects of gonadal hormones on aggressive behavior in the female bank vole was investigated in 10 min home cage tests. Ovariectomized (ovx) or intact females injected with oil, with progesterone (P), with a mixture of progesterone and estrogen (P+E), or with testosterone (T) alone were confronted in a resident-intruder test with unfamiliar, nonoperated females as intruders. Intact females showed aggressive behavior more frequently than ovx females. Ovx females injected with P, with P+E, or with T made significantly more attacks, and these attacks lasted longer than those observed for oil-treated voles. The results indicate that P, the typical female hormone, is responsible for aggressive behavior in female bank voles; however, only T increased the duration of interfemale aggression. Aggr. Behav. 24:63–70, 1998. © 1998 Wiley-Liss, Inc.     

Interdisciplinary Knowledge Translation: Lessons Learned from a Mental Health: Fire Service Collaboration

Collaborative approaches are being increasingly advocated for addressing a variety of health, mental health and social needs for children, youth and families. Factors important for effective knowledge translation of collaborative approaches of service delivery across disciplines, however, have not been rigorously examined. TAPP-C: The Arson Prevention Program for Children is an intervention program for child and adolescent firesetters provided collaboratively by fire service and mental health professionals. The present study examined the adopter, innovation, and dissemination characteristics associated with TAPP-C implementation, protocol adherence and extent of collaboration by 241 community-based fire service professionals from communities across Ontario. Results revealed that dissemination factors are particularly important for understanding program implementation, adherence and cross-discipline collaboration. Moreover, the findings of this study show significant benefits to both within discipline (intra-disciplinary) and across discipline (interdisciplinary) knowledge translation strategies.     

Neurocognitive correlates of white matter quality in adolescent substance users

Background

Progressive myelination during adolescence implicates an increased vulnerability to neurotoxic substances and enduring neurocognitive consequences. This study examined the cognitive manifestations of altered white matter microstructure in chronic marijuana and alcohol-using (MJ + ALC) adolescents.

Methods

Thirty-six MJ + ALC adolescents (ages 16–19) and 36 demographically similar controls were evaluated with diffusion tensor imaging (Bava et al., 2009) and neurocognitive tests. Regions of group difference in fractional anisotropy (FA) and mean diffusivity (MD) were analyzed in relation to cognitive performance.

Results

In users, lower FA in temporal areas related to poorer performance on attention, working memory, and speeded processing tasks. Among regions where users had higher FA than controls, occipital FA was positively associated with working memory and complex visuomotor sequencing, whereas FA in anterior regions was negatively associated with verbal memory performance.

Conclusions

Findings suggest differential influences of white matter development on cognition in MJ + ALC using adolescents than in non-using peers. Neuroadaptation may reflect additive and subtractive responses to substance use that are complicated by competing maturational processes.     

In search of the silver lining: the justice motive fosters perceptions of benefits in the later lives of tragedy victims

Past research has demonstrated that people's need to perceive the world as fair and just leads them to blame and derogate victims of tragedy. The research reported here shows that a positive reaction--bestowing additional meaning on the lives of individuals who have suffered--can also serve people's need to believe that the world is just. In two studies, participants whose justice motive was temporarily heightened or who strongly endorsed the belief that reward and punishment are fairly distributed in the world perceived more meaning and enjoyment in the life of someone who had experienced a tragedy than in the life of someone who had not experienced tragedy, but this pattern was not found for participants whose justice motive was not heightened or who did not strongly endorse a justice belief. These results suggest that being motivated to see the world as just--a motivation traditionally associated with victim derogation--also leads people to perceive a "silver lining" to tragic events.     

'Silent' priming of translation-dependent LTP by ß-adrenergic receptors involves phosphorylation and recruitment of AMPA receptors

The capacity for long-term changes in synaptic efficacy can be altered by prior synaptic activity, a process known as "metaplasticity." Activation of receptors for modulatory neurotransmitters can trigger downstream signaling cascades that persist beyond initial receptor activation and may thus have metaplastic effects. Because activation of β-adrenergic receptors (β-ARs) strongly enhances the induction of long-term potentiation (LTP) in the hippocampal CA1 region, we examined whether activation of these receptors also had metaplastic effects on LTP induction. Our results show that activation of β-ARs induces a protein synthesis-dependent form of metaplasticity that primes the future induction of late-phase LTP by a subthreshold stimulus. β-AR activation also induced a long-lasting increase in phosphorylation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) GluA1 subunits at a protein kinase A (PKA) site (S845) and transiently activated extracellular signal-regulated kinase (ERK). Consistent with this, inhibitors of PKA and ERK blocked the metaplastic effects of β-AR activation. β-AR activation also induced a prolonged, translation-dependent increase in cell surface levels of GluA1 subunit-containing AMPA receptors. Our results indicate that β-ARs can modulate hippocampal synaptic plasticity by priming synapses for the future induction of late-phase LTP through up-regulation of translational processes, one consequence of which is the trafficking of AMPARs to the cell surface.