Basal ganglia outputs map instantaneous position coordinates during behavior.

The basal ganglia (BG) are implicated in many movement disorders, yet how they contribute to movement remains unclear. Using wireless in vivo recording, we measured BG output from the substantia nigra pars reticulata (SNr) in mice while monitoring their movements with video tracking. The firing rate of most nigral neurons reflected Cartesian coordinates (either x- or y-coordinates) of the animal's head position during movement. The firing rates of SNr neurons are either positively or negatively correlated with the coordinates. Using an egocentric reference frame, four types of neurons can be classified: each type increases firing during movement in a particular direction (left, right, up, down), and decreases firing during movement in the opposite direction. Given the high correlation between the firing rate and the x and y components of the position vector, the movement trajectory can be reconstructed from neural activity. Our results therefore demonstrate a quantitative and continuous relationship between BG output and behavior. Thus, a steady BG output signal from the SNr (i.e., constant firing rate) is associated with the lack of overt movement, when a stable posture is maintained by structures downstream of the BG. Any change in SNr firing rate is associated with a change in position (i.e., movement). We hypothesize that the SNr output quantitatively determines the direction, velocity, and amplitude of voluntary movements. By changing the reference signals to downstream position control systems, the BG can produce transitions in body configurations and initiate actions.

Should Contact Precautions Be Used for Patients with MRSA Infection and Colonization in Acute Care Settings?

Are Contact Precautions for Patients with MRSA Useful?MRSA infections lead to substantial morbidity and mortality. Hospitals commonly implement "contact precautions" to reduce MRSA transmission; however, recent studies have challenged the effectiveness of this strategy, and the use of contact precautions has been associated with certain adverse events. This article reviews the existing evidence and proposes a randomized trial to assess the efficacy of contact precautions in preventing MRSA transmission.

How Treatment Effect Heterogeneity Works.

How Treatment Effect Heterogeneity WorksThis Stats, STAT! animated video explores the concept of treatment effect heterogeneity. Differences in the effectiveness of treatments across participants in a clinical trial is important to understand when deciding how to apply clinical trial results to clinical practice.

How Statistical Power Works.

How Statistical Power WorksThis Stats, STAT! animated video explores the concept of statistical power and explains how clinical investigators determine how many participants to enroll in a randomized trial.

How Censoring Works.

How Censoring WorksA common challenge in clinical research is determining the time to occurrence of a given event. This animated video explores the concept of censoring in survival analysis and how investigators deal with ambiguity in the time of an event's occurrence.

Heterotopic ossification after local steroid injection.

Pachydermodactyly (PDD) is a rare, benign disease associated with progressive swelling of the periarticular soft tissue of phalangeal hand joints typically treated with local steroid injections. We present a case of a 37-year-old man with PDD treated with local steroid injections. He later developed heterotopic ossification and para-articular calcifications in the injection sites. Heterotopic ossification is not associated with PDD nor is it a recognised complication of local steroid injections. This is the first case in literature of heterotopic ossification occurring after local steroid injection and brings to attention a new potential complication of a widely performed procedure.

Traditional medicine usage among adult women in Ibadan, Nigeria: a cross-sectional study.

BACKGROUND: Previous research has revealed high rates of traditional medicine usage in Nigeria. Reports of widespread contamination of herbal medicine products and higher rates of noncompliance with Western medications among traditional medicine users have raised concerns about the safety of traditional medicine use. Few studies have explored how demographic factors predict rates of traditional medicine use in the general population. METHODS: We conducted interviews of 748 adult women recruited from the communities in the city of Ibadan, Nigeria from 2013 to 2015. A structured questionnaire was created to collect data on rates of traditional medicine use and demographic factors such as age, education, ethnicity, and occupation. Multivariate logistic regressions were run to examine factors related to traditional medicine use, and the effects were measured with odds ratios (OR) along with 95% confidence interval (95%CI). RESULTS: The overall proportion of traditional medicine use was 81.6%. Women from the Ibo and Hausa ethnic groups were significantly less likely to use traditional medicine than the majority Yoruba group (OR 0.25, 95%CI 0.10-0.63;, OR 0.43, 95%CI 0.24-0.76) respectively). In addition, educated women were less likely than their non-educated counterparts to have used traditional medicine, with the biggest effect seen in women with a secondary education (OR 0.42, 95%CI 0.21-0.85). CONCLUSIONS: We found a high rate of traditional medicine usage, consistent with that found in prior research. A novel finding was the significance of ethnicity as a predictor for usage rates.

Use of Noninvasive Imaging in Giant Cell Arteritis.

Giant cell arteritis (GCA) requires a prompt diagnosis to avoid significant morbidity among the elderly. An accurate diagnosis is also paramount given the side effect profile of long-term corticosteroid treatment. Temporal artery biopsy (TAB) has long remained the gold standard for the diagnosis of GCA but requires an invasive procedure that is not without risk. This article discusses the argument for and against the use of noninvasive imaging including ultrasound, magnetic resonance imaging, and positron emission tomography scanning for the diagnosis of GCA. It also provides a suggested diagnostic algorithm for when to consider noninvasive imaging versus TAB.

Beyond reward prediction errors: the role of dopamine in movement kinematics.

We recorded activity of dopamine (DA) neurons in the substantia nigra pars compacta in unrestrained mice while monitoring their movements with video tracking. Our approach allows an unbiased examination of the continuous relationship between single unit activity and behavior. Although DA neurons show characteristic burst firing following cue or reward presentation, as previously reported, their activity can be explained by the representation of actual movement kinematics. Unlike neighboring pars reticulata GABAergic output neurons, which can represent vector components of position, DA neurons represent vector components of velocity or acceleration. We found neurons related to movements in four directions-up, down, left, right. For horizontal movements, there is significant lateralization of neurons: the left nigra contains more rightward neurons, whereas the right nigra contains more leftward neurons. The relationship between DA activity and movement kinematics was found on both appetitive trials using sucrose and aversive trials using air puff, showing that these neurons belong to a velocity control circuit that can be used for any number of purposes, whether to seek reward or to avoid harm. In support of this conclusion, mimicry of the phasic activation of DA neurons with selective optogenetic stimulation could also generate movements. Contrary to the popular hypothesis that DA neurons encode reward prediction errors, our results suggest that nigrostriatal DA plays an essential role in controlling the kinematics of voluntary movements. We hypothesize that DA signaling implements gain adjustment for adaptive transition control, and describe a new model of the basal ganglia (BG) in which DA functions to adjust the gain of the transition controller. This model has significant implications for our understanding of movement disorders implicating DA and the BG.