Cerebral activations related to ballistic, stepwise interrupted and gradually modulated movements in parkinson patients

Patients with Parkinson's disease (PD) experience impaired initiation and inhibition of movements such as difficulty to start/stop walking. At single-joint level this is accompanied by reduced inhibition of antagonist muscle activity. While normal basal ganglia (BG) contributions to motor control include selecting appropriate muscles by inhibiting others, it is unclear how PD-related changes in BG function cause impaired movement initiation and inhibition at single-joint level. To further elucidate these changes we studied 4 right-hand movement tasks with fMRI, by dissociating activations related to abrupt movement initiation, inhibition and gradual movement modulation. Initiation and inhibition were inferred from ballistic and stepwise interrupted movement, respectively, while smooth wrist circumduction enabled the assessment of gradually modulated movement. Task-related activations were compared between PD patients (N = 12) and healthy subjects (N = 18). In healthy subjects, movement initiation was characterized by antero-ventral striatum, substantia nigra (SN) and premotor activations while inhibition was dominated by subthalamic nucleus (STN) and pallidal activations, in line with the known role of these areas in simple movement. Gradual movement mainly involved antero-dorsal putamen and pallidum. Compared to healthy subjects, patients showed reduced striatal/SN and increased pallidal activation for initiation, whereas for inhibition STN activation was reduced and striatal-thalamo-cortical activation increased. For gradual movement patients showed reduced pallidal and increased thalamo-cortical activation. We conclude that PD-related changes during movement initiation fit the (rather static) model of alterations in direct and indirect BG pathways. Reduced STN activation and regional cortical increased activation in PD during inhibition and gradual movement modulation are better explained by a dynamic model that also takes into account enhanced responsiveness to external stimuli in this disease and the effects of hyper-fluctuating cortical inputs to the striatum and STN in particular

Acculturation and eating disorders in Asian and Caucasian Australian adolescent girls

The present study aimed to compare the attitudes and psychopathology of eating disorders between Asian and Caucasian adolescent girls; and investigate the relationship between acculturation and the attitudes and psychopathology of eating disorders in subgroups of Asian girls. Two groups of non-clinical adolescent girls in Perth, Western Australia, were compared using a survey method. There were 17 Asian and 25 Caucasian adolescent girls, aged 14-17 drawn from private high schools in Perth who were screened using the Eating Attitudes Test (EAT-26), the Eating Disorders Inventory (EDI-2), and an acculturation index. The psychopathology scores for eating disorders of the Asian group were significantly higher than that of the Caucasian group in terms of total EDI-2 score, Interpersonal Distrust, Maturity Fears, Impulse Regulation and Social Insecurity subscales. Eating attitudes measured by Dieting subscale of the EAT-26 was significantly different. Within the Asian group, the less acculturated girls had higher scores on the EAT-26 and the EDI-2 than the more acculturated. Less acculturated Asian girls appeared to have unhealthier attitudes and psychopathology toward eating

Circulating levels of inflammation and the effect on exercise-related changes in bone mass, structure and strength in middle-aged and older men

Chronic, low-grade systematic inflammation has been associated with bone loss and increased fracture risk. We previously reported that exercise improved femoral neck bone mineral density (BMD), geometry and strength and lumbar spine trabecular BMD in middle-aged and older men, but had no effect on markers of inflammation. The aim of this study was to examine the association between basal inflammatory status and the adaptive skeletal responses to exercise. Secondary analysis was completed on 91 men aged 50–79 years who participated in an 18-month program of progressive resistance training plus weight-bearing impact exercise (3 day/week) with and without additional calcium–vitamin D 3 . Markers of inflammation (serum hs-CRP, TNF-α and IL-6) and DXA and QCT-derived BMD, bone structure and strength at the lumbar spine and proximal femur were measured at baseline and 18 months. Multiple regression was used to assess associations between skeletal changes and both baseline levels of individual inflammatory markers and a composite inflammatory index derived from the number of markers categorized into the highest tertile. Baseline serum hs-CRP, TNFα and IL-6 and the composite inflammatory index score were not associated with skeletal changes at any site after adjusting for age, change in lean mass, disease(s)/medication use and adherence to the exercise intervention. In conclusion, this study indicates that basal inflammatory status does not influence the osteogenic response to exercise training in healthy middle-aged and older men. </p

Acculturation, Physical Activity, and Fast-Food Consumption Among Asian-American and Hispanic Adolescents

Previous studies have implicated acculturation to the US as a risk factor for unhealthy behaviors among Hispanic and Asian-American adolescents, including substance use, violence, and unsafe sex. This study examined the association between acculturation and obesity-related behaviors•physical activity and fast-food consumption•among 619 Asian-American and 1385 Hispanic adolescents in Southern California. Respondents completed surveys in 6th and 7th grade. The 6th grade survey assessed acculturation with the AHIMSA acculturation scale and a measure of English language usage. The 7th grade survey assessed frequency of moderate-to-intense physical activity and frequency of eating fast-food. Multiple regression analyses included acculturation and demographic covariates as predictors of physical activity and fast-food consumption. Acculturation to the US, assessed in 6th grade, was significantly associated with a lower frequency of physical activity participation and a higher frequency of fast-food consumption in 7th grade. The significant associations persisted after controlling for covariates and were consistent across gender and ethnic groups. Results suggest that acculturation to the US is a risk factor for obesity-related behaviors among Asian-American and Hispanic adolescents. Health promotion programs are needed to encourage physical activity and healthy diets among adolescents in acculturating families