GABAB receptors in prelimbic cortex and basolateral amygdala differentially influence intertemporal decision making and decline with age.

The ability to decide adaptively between immediate vs. delayed gratification (intertemporal choice) is critical for well-being and is associated with a range of factors that influence quality of life. In contrast to young adults, many older adults show enhanced preference for delayed gratification; however, the neural mechanisms underlying this age difference in intertemporal choice are largely un-studied. Changes in signaling through GABAB receptors (GABABRs) mediate several age-associated differences in cognitive processes linked to intertemporal choice. The current study used a rat model to determine how GABABRs in two brain regions known to regulate intertemporal choice (prelimbic cortex; PrL and basolateral amygdala; BLA) contribute to age differences in this form of decision making in male rats. As in humans, aged rats showed enhanced preference for large, delayed over small, immediate rewards during performance in an intertemporal choice task in operant test chambers. Activation of PrL GABABRs via microinfusion of the agonist baclofen increased choice of large, delayed rewards in young adult rats but did not influence choice in aged rats. Conversely, infusion of baclofen into the BLA strongly reduced choice of large, delayed rewards in both young adult and aged rats. Aged rats further showed a significant reduction in expression of GABABR1 subunit isoforms in the prefrontal cortex, a discovery that is consonant with the null effect of intra-PrL baclofen on intertemporal choice in aged rats. In contrast, expression of GABABR subunits was generally conserved with age in the BLA. Jointly, these findings elucidate a role for GABABRs in intertemporal choice and identify fundamental features of brain maturation and aging that mediate an improved ability to delay gratification.

Systematic review: investigating the added diagnostic value of gadolinium contrast agents for osteomyelitis in the appendicular skeleton.

OBJECTIVE: Osteomyelitis is an infection of the bone marrow. MRI with gadolinium-based contrast is frequently performed for cases of suspected osteomyelitis. The objective of this systematic review is to examine the diagnostic accuracy of contrast-enhanced vs non-contrast-enhanced MRI for osteomyelitis in the appendicular skeleton. MATERIALS AND METHODS: We conducted a systematic review of MRI in the diagnosis of osteomyelitis by searching MEDLINE and EMBASE from January 2000 to March 2020. There were 21 studies that met the inclusion criteria for the systematic review for a total of 1095 patients. Analytic methods were based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Evidence was evaluated using the STARD criteria for evaluation of completeness and transparency of reporting. RESULTS: For diagnosing osteomyelitis in the appendicular skeleton, MRI with gadolinium-based contrast has 89% sensitivity (95% CI, 86-92%), 79% specificity (95% CI, 75-83%), and 90% overall diagnostic accuracy ([SE] = 0.03). For diagnosing osteomyelitis in the appendicular skeleton, MRI without gadolinium-based contrast has a 92% sensitivity (95% CI, 87-96%), 89% specificity (95% CI, 84-93%), and 96% overall diagnostic accuracy ([SE] = 0.03). The median score of included studies was 85% utilizing the STARD criteria with excellent interobserver agreement of 83.4%. Limitations included small sample size of studies, with retrospective designs. CONCLUSION: No evidence was found to suggest an added diagnostic value of gadolinium contrast for the diagnosis of osteomyelitis in the appendicular skeleton. For routine cases of suspected non-spinal osteomyelitis, non-contrast MRI of the area of interest is the next most appropriate study after radiographs.

Advanced Placement Courses for Medical School: A Novel AMed Track to Reduce Financial Burden and Attract Nontraditional Students.

Medical school admissions have become increasingly competitive, creating a pool of nontraditional applicants that seek postbaccalaureate training in biomedical sciences. Several postbaccalaureate and graduate programs developed curricula that, except for learning clinical skills, mirror the learning objectives of the foundational science curricula in medical schools. This education structure provides applicants with a competitive advantage when applying to medical schools. However, basic science curriculum assessments in medical schools have changed to pass/fail scoring systems. As a result, students that participate in preparatory postbaccalaureate and graduate programs cannot show their superior level of knowledge and may find some core foundational science subjects redundant during their pre-clerkship medical education. The aim of this article is to propose an innovative system for matriculation into medical school through the AdvancedMed (AMed) Track, a three-year accelerated medical curriculum in which graduate curricula adopt an advanced placement course called AMed courses. This system would mirror the structure of the high school Advanced Placement (AP) system; therefore, students would take AMed courses similar in rigor to medical school basic science courses. These courses include Anatomy, Histology, Physiology, Cellular Biology, Biochemistry, Genetics, Microbiology, Immunology, Biostatistics, and Epidemiology. All courses would require a scored national standardized test to receive medical school credit toward a three-year accelerated track curriculum. Nontraditional students could choose to study independently and take the AMed standardized examination for credit to enter the AMed Track. Medical schools have the incentive to start an AMed Track because its implementation could lessen the financial burden, reduce time spent in medical school, and increase the participation of nontraditional medical students.

Effectiveness of PitchSafe on Knowledge and Attitude of Baseball-Related Concussion.

Background Traumatic brain injuries (TBIs), specifically concussions, affect many athletes and have dangerous immediate and long-term sequelae. Lack of awareness surrounding concussion impedes prevention, identification, and treatment. This study aims to assess parental knowledge and attitudes regarding concussions in youth baseball before and after administering an educational intervention called PitchSafe. PitchSafe is a short video that contains examples of baseball-related head injuries such as collisions, falls, and direct hits by baseballs; the signs and symptoms of a concussion; testimony from a former baseball player who sustained a TBI playing baseball; and a brochure detailing the potential signs, symptoms, and treatment plans associated with concussions. Methodology The Rosenbaum Concussion Knowledge and Attitudes Survey (RoCKAS) was used to assess three indices of parental understanding of concussion: Concussion Knowledge Index (CKI), Concussion Attitudes Index (CAI), and signs and symptoms of concussions (SS). The RoCKAS was administered at baseline and after the PitchSafe tool was administered. Parents were re-assessed one year following the initial distribution of survey materials utilizing the long-term follow-up (LTFU) RoCKAS. A paired sample t-test was conducted to compare the baseline, post-intervention (PI), and LTFU CKI, CAI, and SS among participants. Results The mean scores for CKI were 68% ± 12%, 76% ± 4%, and 76% ± 5% for baseline, PI, and LTFU, respectively. The mean scores for SS were 46% ± 20%, 62% ± 14%, and 64% ± 16% for baseline, PI, and LTFU, respectively. The mean scores for CAI were 87% ± 6%, 91% ± 5%, and 92% ± 4% for baseline, PI, and LTFU, respectively. Conclusions PitchSafe increased youth baseball parents' long-term knowledge of concussions, ability to identify signs and symptoms of concussions, and may promote safer attitudes toward concussions. These findings support more widespread use of educational tools through social media and in clinical settings.

Testicular hormones mediate robust sex differences in impulsive choice in rats.

Impairments in choosing optimally between immediate and delayed rewards are associated with numerous psychiatric disorders. Such 'intertemporal' choice is influenced by genetic and experiential factors; however, the contributions of biological sex are understudied and data to date are largely inconclusive. Rats were used to determine how sex and gonadal hormones influence choices between small, immediate and large, delayed rewards. Females showed markedly greater preference than males for small, immediate over large, delayed rewards (greater impulsive choice). This difference was neither due to differences in food motivation or reward magnitude perception, nor was it affected by estrous cycle. Ovariectomies did not affect choice in females, whereas orchiectomies increased impulsive choice in males. These data show that male rats exhibit less impulsive choice than females and that this difference is at least partly maintained by testicular hormones. These differences in impulsive choice could be linked to gender differences across multiple neuropsychiatric conditions.

Optogenetic dissection of basolateral amygdala contributions to intertemporal choice in young and aged rats.

Across species, aging is associated with an increased ability to choose delayed over immediate gratification. These experiments used young and aged rats to test the role of the basolateral amygdala (BLA) in intertemporal decision making. An optogenetic approach was used to inactivate the BLA in young and aged rats at discrete time points during choices between levers that yielded a small, immediate vs. a large, delayed food reward. BLA inactivation just prior to decisions attenuated impulsive choice in both young and aged rats. In contrast, inactivation during receipt of the small, immediate reward increased impulsive choice in young rats but had no effect in aged rats. BLA inactivation during the delay or intertrial interval had no effect at either age. These data demonstrate that the BLA plays multiple, temporally distinct roles during intertemporal choice, and show that the contribution of BLA to choice behavior changes across the lifespan.