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We investigated hyposensitivity after amphetamine in early (postnatal Day 30; P30) and late (P45) adolescent rats compared to adults (P70) in experiment 1. Locomotor activity was measured for 1 hr after the first (acute) and second (24 hr later) injection of amphetamine (0.5 or 1.5 mg/kg). P30 and P45 rats were transiently hypoactive compared to adults, as indicated by reduced locomotor activity after acute amphetamine and enhanced activity after the second injection in adolescents only. In experiment 2, ovariectomy did not alter locomotor activity during habituation at any age compared to intact rats, and, as for intact adolescents, ovariectomized adolescents continued to be less active after amphetamine than adults, suggesting gonadal immaturity alone cannot account for age differences in experiment 1. However, ovariectomy attenuated the increase in activity after the second treatment. In experiment 3 involving untreated rats, tyrosine hydroxylase immunoreactivity was reduced in P30, P40, and P50 compared to P90 rats in the nucleus accumbens core and the medial prefrontal cortex. Thus, adolescents may have an increased threshold of behavioral activation that can be overcome with either a higher dose or with repeated amphetamine treatment, and may be related to changes in the dopamine system over development.

BackgroundAdministration of exogenous corticosterone is an effective preclinical model of depression, but its use has involved primarily adult rodents. Using two different procedures of administration drawn from the literature, we explored the possibility of exogenous corticosterone models in adolescence, a time of heightened risk for mood disorders in humans.MethodsIn experiment 1, rats were injected with 40 mg/kg corticosterone or vehicle from postnatal days 30 to 45 and compared with no injection controls on behavior in the elevated plus maze (EPM) and the forced swim test (FST). Experiment 2 consisted of three treatments administered to rats from postnatal days 30 to 45 or as adults (days 70 to 85): either corticosterone (400 μg/ml) administered in the drinking water along with 2.5% ethanol, 2.5% ethanol or water only. In addition to testing on EPM, blood samples after the FST were obtained to measure plasma corticosterone. Analysis of variance (ANOVA) and alpha level of P < 0.05 were used to determine statistical significance.ResultsIn experiment 1, corticosterone treatment of adolescent rats increased anxiety in the EPM and decreased immobility in the FST compared to no injection control rats. However, vehicle injected rats were similar to corticosterone injected rats, suggesting that adolescent rats may be highly vulnerable to stress of injection. In experiment 2, the intake of treated water, and thus doses delivered, differed for adolescents and adults, but there were no effects of treatment on behavior in the EPM or FST. Rats that had ingested corticosterone had reduced corticosterone release after the FST. Ethanol vehicle also affected corticosterone release compared to those ingesting water only, but differently for adolescents than for adults.ConclusionsThe results indicate that several challenges must be overcome before the exogenous corticosterone model can be used effectively in adolescents.

Background Knitting as a creative practice has a reputation for being therapeutic. There are many programs that use crafts as a method of creating social community and reducing anxiety for youth; however, there is no existing research that demonstrates these benefits. We designed a novel study to explore the benefits of a social skills knitting group on engagement and anxiety for youth with neurodevelopmental disorders. Objectives 1. To evaluate the social engagement experience of youth with neurological conditions participating in the KneuroKnits program. 2. Evaluate the impact of KneuroKnits intervention on anxiety levels of participants. Design/Methods We designed a 4-week knitting group for youth with neurodevelopmental disorders and acquired brain injuries. Each session included a lesson involving a knitting skill and a social skill. To evaluate social engagement, we used the Self-reported Experience of Activity Settings (SEAS) questionnaire at the first and final sessions. The five subcategories of the SEAS (Personal Growth, Psychological Engagement, Social Belonging, Meaningful Interactions and Choice & Control) were analyzed following the first and the last session. Qualitative interviews were conducted with participants, parents, and facilitators in the month following the final session and were analyzed using an interpretive phenomenological approach to outline commonly occurring themes in social engagement. To evaluate anxiety levels, participants completed the State-Trait Anxiety Inventory (STAI) at the beginning and end of the first and final sessions, respectively, and the Symptom Checklist-90-R (SCL-90) anxiety subscale; qualitative analysis included themes involving levels of anxiety from the interviews. Results There were 14 total participants with a mean age of 17.4 ± 2.2 years. Participants had primary diagnoses of ASD (n=9), acquired brain injury/concussion (n=4), and developmental coordination disorder (n=1). Social engagement results for the SEAS questionnaire showed a general increase in mean scores of all subcategories with a significant increase in the category of “Meaningful Interactions (p=0.02). This quantitatively demonstrated that the group had an impact on creating meaningful social connection. Qualitative analysis of the interviews revealed three commonly occurring themes: The balance of organic and facilitated social interaction, a sense of community from shared experience and direct benefits of knitting (pride, productivity, relaxation, a choice to be social). For the evaluation of anxiety levels, the STAI demonstrated a significant decrease in anxiety following both Session 1 (p=0.02) and Session 4 (p=0.006). The SCL-90-R Anxiety subsection scores significantly decreased between the first and final session (p=0.01). Participants voiced that the sessions made them feel calmer. Conclusion This knitting group merged a creative skill and social skill, and was novel in its approach to studying social engagement and anxiety within this population. Our study found that participants, their families and facilitators found KneuroKnits to be a valuable and rewarding program. Further study is needed in a larger sample to confirm our findings.

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