The Association of Dexmedetomidine with Firing Properties in Pallidal Neurons.

BACKGROUND: Microelectrode recordings (MERs) are used during deep brain stimulation surgery (DBS) to optimize patient outcomes and provide a unique method of collecting data regarding neurological conditions. However, MERs can be affected by anesthetics such as dexmedetomidine. Little is known about the effects of dexmedetomidine (DEX) on the globus pallidus interna (GPi), a common target for DBS. The primary aim of this study is to investigate the hypothesis that DEX is associated with alterations in GPi MERs. METHODS: We conducted a retrospective analysis comparing MERs from patients with Parkinson's disease (PD) and dystonia who underwent insertion of DBS of the GPi under DEX sedation with those who went through the same procedure without DEX (No DEX). RESULTS: Firing rates for GPi neurons in the DEX group were lower (57.44 ± 2.04; mean ± SEM, n = 163 cells) than the No DEX group (69.53 ± 2.06, n = 112 cells, P < 0.0001). Overall, DEX was associated with a greater proportion of GPi cells classified as firing in bursty pattern compared to our No DEX group. (29.41%, n = 153 vs 14.81%, n = 108, P = 0.008). This effect was present for both PD and dystonia patients who underwent the procedure. High doses of DEX were associated with lower firing rates than low doses. CONCLUSIONS: Our results suggest that DEX is associated with a decrease in GPi firing rates and are associated with an increase in burstiness. Furthermore, these effects are similar between dystonia and PD patients. Lastly, the effects of DEX may differ between high doses and low doses.

Higher rates of sex evolve during adaptation to more complex environments.

A leading hypothesis for the evolutionary maintenance of sexual reproduction proposes that sex is advantageous because it facilitates adaptation. Changes in the environment stimulate adaptation but not all changes are equivalent; a change may occur along one or multiple environmental dimensions. In two evolution experiments with the facultatively sexual rotifer Brachionus calyciflorus, we test how environmental complexity affects the evolution of sex by adapting replicate populations to various environments that differ from the original along one, two, or three environmental dimensions. Three different estimates of fitness (growth, lifetime reproduction, and population density) confirmed that populations adapted to their new environment. Growth measures revealed an intriguing cost of complex adaptations: populations that adapted to more complex environments lost greater amounts of fitness in the original environment. Furthermore, both experiments showed that B. calyciflorus became more sexual when adapting to a greater number of environmental dimensions. Common garden experiments confirmed that observed changes in sex were heritable. As environments in nature are inherently complex these findings help explain why sex is maintained in natural populations.

Examining the Effect of Virtual Learning on Canadian Pre-Clerkship Medical Student Well-Being During the COVID-19 Pandemic.

Introduction: The restrictions of the COVID-19 pandemic resulted in the broad and abrupt incorporation of virtual/online learning into medical school curricula. While current literature explores the effectiveness and economic advantages of virtual curricula, robust literature surrounding the effect of virtual learning on medical student well-being is needed. This study aims to explore the effects of a predominantly virtual curriculum on pre-clerkship medical student well-being. Methods: This study followed a constructivist grounded theory approach. During the 2020-2021 and 2021-2022 academic years, students in pre-clerkship medical studies at Western University in Canada were interviewed by medical student researchers over Zoom. Data was analyzed iteratively using constant comparison. Results: We found that students experiencing virtual learning faced two key challenges: 1) virtual learning may be associated with an increased sense of social isolation, negatively affecting wellbeing, 2) virtual learning may impede or delay the development of trainees' professional identity. With time, however, we found that many students were able to adapt by using protective coping strategies that enabled them to appreciate positive elements of online learning, such as its flexibility. Discussion: When incorporating virtual learning into medical education, curriculum developers should prioritize optimizing existing and creating new ways for students to interact with both peers and faculty to strengthen medical student identity and combat feelings of social isolation.

Medical Students as Educators: Addressing Teaching Skills Through a Pre-clerkship Development Group.

In medicine, effective teaching is requisite for both successful patient care and trainee development. However, opportunities for medical students to gain exposure to pedagogical principles and hone teaching skills are currently limited. Our initiative provides avenues for medical students to intentionally develop their teaching skill set from an early stage.

Adverse psychiatric effects of disease-modifying therapies in multiple Sclerosis: A systematic review.

BACKGROUND: Psychiatric comorbidity is prevalent in persons with multiple sclerosis (MS). Few studies have assessed whether second-generation disease-modifying therapies (DMT) are associated with adverse psychiatric effects. OBJECTIVE: We aimed to systematically review the literature regarding the APEs associated with natalizumab, fingolimod, dimethyl fumarate, teriflunomide and alemtuzumab in MS. As a secondary objective, we evaluated changes in anxiety or depression scores following treatment with the aforementioned DMTs. METHODS: We searched MEDLINE, EMBASE, International Pharmaceutical Abstracts, PsychINFO, Central Register of Controlled Trials & Cochrane database of systematic reviews for published studies, and clinicaltrials.gov and regulatory documents from the US and Canada for unpublished studies. Data sources were searched from inception to September 2017. Studies reporting adverse psychiatric effects involving any DMT of interest were included. We report the incidence proportions of the adverse psychiatric effects and, where applicable, risk differences between DMT-exposed and unexposed individuals along with the corresponding 95% confidence intervals. We calculated the standardized mean differences (SMD) of changes in anxiety and depression scores if reported as study outcomes, and pooled the data using random effects meta-analysis. RESULTS: Of 4389 abstracts screened, 78 met the inclusion criteria, including 48 clinical trials, 28 observational studies and 2 case reports. Depression was the most commonly reported adverse psychiatric effect. Incidence proportions for all adverse psychiatric effects ranged from 0 to 24.7%. None of the DMT studied were associated with a statistically significant increased risk of any adverse psychiatric effect (range of risk difference: -7.69% [95%CI: -16.06%, 5.56%] to 6.67 [-8.56, 15.59]). Eighteen studies examined changes in depression or anxiety following fingolimod, natalizumab or dimethyl fumarate treatment; depression symptoms improved in fingolimod-treated groups (SMD [95%CI]: 1.18 [0.17, 2.19]). We did not identify studies examining changes in these outcomes following treatment with any of the other DMTs. CONCLUSION: The DMTs reviewed were not associated with an increased risk of adverse psychiatric effect in MS, and some may reduce the incidence of depressive symptoms. This may reflect either a positive direct effect (e.g. immune modulation) or an indirect effect arising due to a positive impact on disease activity or course.