► The mirror neuron system sub-serves both motor imagery and action observation. ► Both motor imagery and action observation play a role in motor learning. ► In this study we compared these ...strategies in learning a novel complex motor task. ► Action observation revealed better than motor imagery as a motor learning strategy. ► This is relevant in educational activities, sport training and neurorehabilitation.
Both motor imagery and action observation have been shown to play a role in learning or re-learning complex motor tasks. According to a well accepted view they share a common neurophysiological basis in the mirror neuron system. Neurons within this system discharge when individuals perform a specific action and when they look at another individual performing the same or a motorically related action. In the present paper, after a short review of literature on the role of action observation and motor imagery in motor learning, we report the results of a kinematics study where we directly compared motor imagery and action observation in learning a novel complex motor task. This involved movement of the right hand and foot in the same angular direction (in-phase movement), while at the same time moving the left hand and foot in an opposite angular direction (anti-phase movement), all at a frequency of 1Hz. Motor learning was assessed through kinematics recording of wrists and ankles. The results showed that action observation is better than motor imagery as a strategy for learning a novel complex motor task, at least in the fast early phase of motor learning. We forward that these results may have important implications in educational activities, sport training and neurorehabilitation.
Whereas 16S rRNA gene amplicon sequencing quantifies relative abundances of bacterial taxa, variation in total bacterial load between samples restricts its ability to reflect absolute concentrations ...of individual bacterial species. Quantitative PCR (qPCR) can quantify individual species, but it is not practical to develop a suite of qPCR assays for every bacterium present in a diverse sample. We sought to determine the accuracy of an inferred measure of bacterial concentration using total bacterial load and relative abundance. We analyzed 1,320 samples from 20 women with a history of frequent bacterial vaginosis who self-collected vaginal swabs daily over 60 days. We inferred bacterial concentrations by taking the product of species relative abundance (assessed by 16S rRNA gene amplicon sequencing) and bacterial load (measured by broad-range 16S rRNA gene qPCR). Log
-converted inferred concentrations correlated with targeted qPCR (
= 0. 935,
< 2.2e-16) for seven key bacterial species. The mean inferred concentration error varied across bacteria, with rarer bacteria associated with larger errors. A total of 92% of the >0.5-log
errors occurred when the relative abundance was <10%. Many errors occurred during early bacterial expansion from or late contraction to low abundance. When the relative abundance of a species is >10%, inferred concentrations are reliable proxies for targeted qPCR in the vaginal microbiome. However, targeted qPCR is required to capture bacteria at low relative abundance and is preferable for characterizing growth and decay kinetics of single species.
Microbiome studies primarily use 16S rRNA gene amplicon sequencing to assess the relative abundance of bacterial taxa in a community. However, these measurements do not accurately reflect absolute taxon concentrations. We sought to determine whether the product of species' relative abundance and total bacterial load measured by broad-range qPCR is an accurate proxy for individual species' concentrations, as measured by taxon-specific qPCR assays. Overall, the inferred bacterial concentrations were a reasonable proxy of species-specific qPCR values, particularly when bacteria are present at a higher relative abundance. This approach offers an opportunity to assess the concentrations of bacterial species and how they change in a community over time without developing individual qPCR assays for each taxon.
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The HIV reservoir is a population of 1–10 million anatomically dispersed, latently infected memory CD4+ T cells in which HIV DNA is quiescently integrated into human chromosomal DNA. When ...antiretroviral therapy (ART) is stopped and HIV replication initiates in one of these cells, systemic viral spread resumes, rekindling progression to AIDS. Therefore, HIV latency prevents cure. The detection of many populations of identical HIV sequences at unique integration sites implicates CD4+ T cell proliferation as the critical driver of reservoir sustainment after a prolonged period of effective ART. Initial reservoir formation occurs during the first week of primary infection usually before ART is started. While empirical data indicates that both de novo infection and cellular proliferation generate latently infected cells during early untreated infection, it is not known which of these mechanisms is predominant. We developed a mathematical model that recapitulates the profound depletion and brisk recovery of CD4+ T cells, reservoir creation, and viral load trajectory during primary HIV infection. We extended the model to stochastically simulate individual HIV reservoir clones. This model predicts the first detection of HIV infected clones approximately 5 weeks after infection as has recently been shown in vivo and suggests that substantial, uneven proliferation among clones during the recovery from CD4+ lymphopenia is the most plausible explanation for the observed clonal reservoir distribution during the first year of infection.
•Transgender (TG) adults reported more psychological distress than cisgender adults.•TG adults were more likely to report suicidality and self-injury.•Alcohol and drug use outcomes were similar for ...TG and cisgender adults.•TG nonbinary people had the highest odds of substance and mental health problems.
Transgender individuals experience numerous health disparities relative to cisgender individuals. However, most transgender-health studies have focused on convenience samples with limited generalizability. This study utilized data from the 2016–2018 TransPop Study, the first national probability sample of transgender adults (n=274) with a cisgender comparison sample (n=1162). Using multivariable logistic regression, adjusted for demographics, we compared the prevalence of hazardous drinking, problematic drug use, serious psychological distress, suicidality, and non-suicidal self-injury between transgender and cisgender individuals and among transgender men (n=78), transgender women (n=120), and transgender nonbinary individuals (n=76). Among transgender individuals, 28.2% (95%CI 21.2–35.2) and 31.2% (95%CI 23.8–38.7) reported hazardous drinking and problematic drug use, respectively; 44.4% (95% CI 35.8–53.0) reported recent suicidal ideation, 6.9% (95% CI 2.3–11.5) reported a recent suicide attempt, and 21.4% (95% CI 14.5%-28.4%) reported recent non-suicidal self-injury. In their lifetime, 81.3% (95%CI 75.1–87.5) of transgender respondents had suicidal ideation, 42.0% (95%CI 34.2–49.8) had attempted suicide, and 56.0% (95% CI 48.2–63.8) reported non-suicidal self-injury. Most (81.5%; 95%CI 75.5–87.5) had utilized formal mental health care and 25.5% (95%CI 18.5–32.4) had sought informal mental health support. There were no differences in alcohol or drug-use outcomes between transgender and cisgender adults. Compared to cisgender adults, transgender adults had higher odds of serious psychological distress (aOR=3.1; 95%CI 1.7–5.7), suicidal ideation (recent: aOR=5.1, 95%CI 2.7–9.6); lifetime: aOR=6.7, 95%CI 3.8–11.7), lifetime suicide attempts (aOR=4.4, 95%CI 2.4–8.0), and non-suicidal self-injury (recent: aOR=13.0, 95%CI 4.8–35.1); lifetime: aOR=7.6, 95%CI 4.1–14.3). Transgender nonbinary adults had the highest odds for all outcomes, including substance use outcomes. Findings from these national probability samples support those of earlier convenience-sample studies showing mental health disparities among transgender adults relative to cisgender adults, with nonbinary individuals at highest risk. These findings also highlight variations in risk across sub-groups of transgender individuals.
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