Motor neuron output in the crustacean cardiac ganglion is organized and maintained by homeostatic conductance relationships

Generating appropriate and functional neuronal output is a matter of fundamental importance to nervous systems across species and phyla. Potential perturbations to a neurons intrinsic excitability alone include Hebbian style plasticity, ion channel turnover and neuromodulation. With these dynamic processes in place, it is remarkable that neurons are able to maintain stable and functional output throughout the life of an organism. Yet little is known about the cellular mechanisms in neurons and networks which act to stabilize functional output. Here we utilize large cell motor neurons of the Cancer borealis cardiac ganglion to investigate how these cell's important burst output is generated, maintained and synchronized across cells in a rhythmic motor network. We find that large cell motor neurons utilize multiple intrinsic currents to mediate burst potentials, and these currents are in part localized to the LC somata, distal from action potential generating currents. Next we examine the functional organization of these intrinsic currents and show that LC motor neurons, which have synchronous burst activity during normal network behavior, have differential intrinsic tuning even across LCs in a single network. This differential tuning results in conserved voltage output across LCS in part due to compensatory conductance relationships.Includes bibliographical references (pages 139-148)

A Pilot Study Examining Exercise Self-Efficacy as a Mediator for Walking Behavior in College-Age Women

Since mechanisms of behavior change are not always evaluated in physical activity interventions, current interventions are limited until these mechanisms are better understood (Bauman, Sallis, Dzewaltowski, & Owen, 2002). Therefore, studies are needed that examine mediating variables, derived from theory, in the design, implementation, and evaluation of interventions. A mediator is a variable that must be included in an intervention in order for a specific change in a dependent variable or outcome to occur (MacKinnon, 2008). MacKinnon (2008) describes several methods of identifying mediators using statistical procedures, including the causal inference approach, difference in coefficients, product of coefficients, structural equation modeling and bootstrap estimates of the mediated effect

Environmental protection requirements for scout/shuttle auxiliary stages

The requirements for enabling the Scout upper stages to endure the expected temperature, mechanical shock, acoustical and mechanical vibration environments during a specified shuttle mission were determined. The study consisted of: determining a shuttle mission trajectory for a 545 kilogram (1200 pound) Scout payload; compilation of shuttle environmental conditions; determining of Scout upper stages environments in shuttle missions; compilation of Scout upper stages environmental qualification criteria and comparison to shuttle mission expected environments; and recommendations for enabling Scout upper stages to endure the exptected shuttle mission environments

Correlated Levels of mRNA and Soma Size in Single Identified Neurons: Evidence for Compartment-specific Regulation of Gene Expression

In addition to the overall complexity of transcriptional regulation, cells also must take into account the subcellular distribution of these gene products. This is particularly challenging for morphologically complex cells such as neurons. Yet the interaction between cellular morphology and gene expression is poorly understood. Here we provide some of the first evidence for a relationship between neuronal compartment size and maintenance of mRNA levels in neurons. We find that single-cell transcript levels of 18S rRNA, GAPDH, and EF1-alpha, all gene products with primary functions in the cell soma, are strongly correlated to soma size in multiple distinct neuronal types. Levels of mRNA for the K+ channel shal, which is localized exclusively to the soma, are negatively correlated with soma size, suggesting that gene expression does not simply track positively with compartment size. Conversely, levels of beta-actin and beta-tubulin mRNA, which are major cytoskeletal proteins of neuronal processes, do not correlate with soma size, but are strongly correlated with one another. Additionally, actin/tubulin expression levels correlate with voltage-gated ion channels that are uniquely localized to axons. These results suggest that steady-state transcript levels are differentially regulated based on the subcellular compartment within which a given gene product primarily acts

Women Bound to Be Active: One Year Follow-Up to an Innovative Pilot Intervention to Increase Physical Activity and Self-Worth in Women

The purpose of this investigation was to assess the effectiveness of a lifestyle intervention (a women’s book club; Women Bound to be Active) in promoting long-term physical activity (PA). Thirty-five women (26-70 years; mean age 50.6 years) completed the 8-month intervention and participated in the one-year follow-up. At follow-up, PA returned to baseline levels; however, self-worth and body mass index significantly improved. Women were more knowledgeable about PA at follow-up; however, they failed to maintain PA after the intervention. Components of the intervention were effective in improving self-worth and lowering BMI at one-year follow-up. To enhance long-term PA adherence continued research and intervention modifications are needed

An Examination of the Effectiveness of an 8-Week Bikram Yoga Program on Mindfulness, Perceived Stress, and Physical Fitness

Previous research reports positive effects of yoga on health. The physical and psychological outcomes of participation in Bikram yoga are under-researched despite its increasing popularity, and this type of yoga may be significant with regards to stress management due to its unique method of practice. This study was designed to assess changes in levels of mindfulness, perceived stress, and physical fitness after participation in an 8-week Bikram yoga program. Fifty-one participants aged 20–54 years (mean, 31.57 years) were recruited by word of mouth from a large university located in the Northwestern United States. Participants attended a minimum of 20 Bikram sessions over 8 weeks. Changes in mindfulness (Five-Facet Mindfulness Questionnaire), perceived stress (Perceived Stress Scale), and physical fitness (resting heart rate, 1-mile walk, sit-and-reach, total-body rotation, and single-leg balance) were measured. Eight weeks of Bikram yoga improved mindfulness, perceived stress, cardiorespiratory endurance, flexibility and balance (p \u3c 0.01). Mindfulness was negatively correlated with perceived stress (r=−0.43, p \u3c 0.01) and resting heart rate (r=−0.30, p \u3c 0.05). The results show that Bikram yoga positively affected psychological and physical health in the sample population. This information can be used to further the understanding of mind-body based programs, and how Bikram yoga may give people the tools to decrease perceived stress, potentially having an effect on chronic stress-related illnesses

\u3cem\u3eWomen Bound to Be Active\u3c/em\u3e (Year 3 & 4): Can a Book Club Help Women Overcome Barriers to Physical Activity and Improve Self-Worth?

Little progress has been made toward increasing physical activity (PA) in women. This study aimed to determine if an 8-month theory-based book club intervention (Women Bound to Be Active) was effective in increasing: (a) self-worth, (b) benefits relative to barriers to PA, and (c) PA in women (n=51). Findings suggested a book-club was effective for improving: self-worth, the benefits relative to barriers to PA, and possibly participation in PA. This is an innovative model to help women become more active and learn skills that may enable them to be active on their own long after a PA program has ended

Intrinsic mechanisms in the gating of resurgent Na+ currents

The resurgent component of the voltage-gated sodium current (

Intracellular FGF14 (iFGF14) is required for spontaneous and evoked firing in cerebellar Purkinje neurons and for motor coordination and balance

Mutations in FGF14, which encodes intracellular fibroblast growth factor 14 (iFGF14), have been linked to spinocerebellar ataxia (SCA27). In addition, mice lacking Fgf14 (Fgf14(−/−)) exhibit an ataxia phenotype resembling SCA27, accompanied by marked changes in the excitability of cerebellar granule and Purkinje neurons. It is not known, however, whether these phenotypes result from defects in neuronal development or if they reflect a physiological requirement for iFGF14 in the adult cerebellum. Here, we demonstrate that the acute and selective Fgf14-targeted short hairpin RNA (shRNA)-mediated in vivo “knock-down” of iFGF14 in adult Purkinje neurons attenuates spontaneous and evoked action potential firing without measurably affecting the expression or localization of voltage-gated Na(+) (Nav) channels at Purkinje neuron axon initial segments. The selective shRNA-mediated in vivo “knock-down” of iFGF14 in adult Purkinje neurons also impairs motor coordination and balance. Repetitive firing can be restored in Fgf14-targeted shRNA-expressing Purkinje neurons, as well as in Fgf14(−/−) Purkinje neurons, by prior membrane hyperpolarization, suggesting that the iFGF14-mediated regulation of the excitability of mature Purkinje neurons depends on membrane potential. Further experiments revealed that the loss of iFGF14 results in a marked hyperpolarizing shift in the voltage dependence of steady-state inactivation of the Nav currents in adult Purkinje neurons. We also show here that expressing iFGF14 selectively in adult Fgf14(−/−) Purkinje neurons rescues spontaneous firing and improves motor performance. Together, these results demonstrate that iFGF14 is required for spontaneous and evoked action potential firing in adult Purkinje neurons, thereby controlling the output of these cells and the regulation of motor coordination and balance

Do physical education teachers and general teachers differ in their implicit anti-fat bias?

The purpose of this study was to examine implicit attitudes of physical education (PE) and non-PE teachers towards overweight children stratified by gender, age, and body mass index. Two hundred school teachers (50% PE and 50% non-PE), aged 23-60 (mean=33.5 years) from Hong Kong, China, completed the validated implicit association test to measure attitudes towards overweight children. On the good-bad scale, there were no significant differences between scores for type of teacher. Younger teachers showed more weight discrimination against overweight students compared to their older counterparts. The interaction between type of teacher and gender was significant for the motivated-lazy score. Compared to PE teachers, non-PE teachers demonstrated less discrimination toward the overweight students on motivated-lazy score. Teachers demonstrated implicit weight discrimination toward overweight students. PE teachers are more prone to negative stereotypes related to motivation and laziness. The order of greatest overweight discrimination against overweight students was (1) male PE teachers, (2) female PE teachers, (3) non-PE female teachers and (4) non-PE male teachers