A Dynamical Systems Approach to Characterizing Brain–Body Interactions during Movement: Challenges, Interpretations, and Recommendations

Brain–body interactions (BBIs) have been the focus of intense scrutiny since the inception of the scientific method, playing a foundational role in the earliest debates over the philosophy of science. Contemporary investigations of BBIs to elucidate the neural principles of motor control have benefited from advances in neuroimaging, device engineering, and signal processing. However, these studies generally suffer from two major limitations. First, they rely on interpretations of ‘brain’ activity that are behavioral in nature, rather than neuroanatomical or biophysical. Second, they employ methodological approaches that are inconsistent with a dynamical systems approach to neuromotor control. These limitations represent a fundamental challenge to the use of BBIs for answering basic and applied research questions in neuroimaging and neurorehabilitation. Thus, this review is written as a tutorial to address both limitations for those interested in studying BBIs through a dynamical systems lens. First, we outline current best practices for acquiring, interpreting, and cleaning scalp-measured electroencephalography (EEG) acquired during whole-body movement. Second, we discuss historical and current theories for modeling EEG and kinematic data as dynamical systems. Third, we provide worked examples from both canonical model systems and from empirical EEG and kinematic data collected from two subjects during an overground walking task

The effects of an acute exercise bout on GH and IGF-1 in prediabetic and healthy African Americans: A pilot study investigating gene expression

The incidence of pre-diabetes (PD) and Type-2 Diabetes Mellitus (T2D) is a worldwide epidemic. African American (AA) individuals are disproportionately more likely to become diabetic than other ethnic groups. Over the long-term, metabolic complications related to diabetes result in significant alterations in growth hormone (GH) and insulin-like growth factor-1 (IGF-1). Considering the limited exercise-related studies in the area of gene expression changes with disease progression, the objective of this study was to examine differences in exercise-induced gene expression related to the GH and IGF-1 pathways in peripheral blood mononuclear cells (PBMCs) of healthy (CON) and PD AA individuals. Design: Ten subjects [5 PD (age = 35±9.3 yr, BMI = 32.1±4.0, FBG = 101.8±1.3 mg/dl) and 5 CON (age = 31±9.4 yr, BMI = 29.4±5.2, FBG = 82.8±9.7 mg/dl)] had blood drawn for RNA isolation prior to exercise (Pre), immediately following acute moderate intensity exercise on a treadmill (Post-1), 6-hours post (Post-6), and 24-hours post (Post-24). Isolation of mRNA from PBMCs was performed using ficoll separation, while the profiling of mRNA expression was performed using Illumina beadchip arrays with standard protocols. Scan results were statistically analyzed for a specific list of genes related to GH and IGF-1. GH and IGF-1 protein levels were also assessed in each sample. To address issues of normality, all GH and IGF-1 data were log-transformed prior to analysis. Statistical significance was set at p<0.05. Results: Group differences for GH2 variant 2 (p = 0.070) and GH2 variant 3 (p = 0.059) were coupled with significant alterations in IGF-1 mRNA over time (p = 0.024). A significant interaction between group and time was observed for GHRH mRNA (p = 0.008). No group differences were observed in GH AUC (p = 0.649), ?GH (p = 0.331), GHrec (p = 0.294), or IGF-1 AUC (p = 0.865), representing a similar exercise-induced GH and IGF-1 response for both groups. Conclusions: Analysis of GH and IGF-1 related-gene expression indicates that mild elevations in fasting blood glucose and exercise-induced alterations in gene expression are impacted by the prediabetic state

A preliminary investigation of acute exercise intensity on memory and BDNF isoform concentrations

Little is known about the biological mechanisms underlying the beneficial effect of acute exercise on memory or the influence of single nucleotide polymorphisms (SNPs) on this effect. Brain-derived neurotrophic factor (BDNF) is a putative biological mechanism, and while findings from human studies are equivocal, they have neglected to assess how exercise affects individual BDNF isoform (proBDNF, mBDNF) concentrations in serum or the influence of the BDNF val66met SNP on BDNF isoform concentrations. Therefore, the objective of this study was to conduct an exploratory assessment of the effect of acute exercise intensity on memory performance and BDNF isoform concentrations relative to carrier status of the BDNF val66met SNP met allele and to provide guidance for future, fully-powered trials. Memory and BDNF isoform concentrations were assessed in three exercise groups (light intensity, vigorous intensity, and non-exercise) relative to BDNF met carrier status. Analyses revealed that BDNF isoform concentrations and memory were differentially affected by exercise intensity and BDNF met carrier status. Vigorous intensity exercise increased mBDNF, and BDNF met carriers had lower mBDNF concentration. Light intensity exercise improved memory, and over 24 h, memory was worse for BDNF met carriers. Implications from this work will help direct future mechanistic studies of the exercise-memory relationship

Associations of actigraphy‐assessed sleep variables with adiposity and serum cardiometabolic outcomes in emerging adults

SummaryThis study assessed associations of actigraphy‐assessed sleep with adiposity and serum cardiometabolic outcomes in emerging adults, and whether sex and race modified these associations. Data on 147 emerging adults (age = 19.4 ± 1.3 years; body mass index = 26.4 ± 7.0 kg m$^{−2}$; 59% female; 65% White) from RIGHT Track Health were used. Actigraphy‐based sleep measures included sleep duration, sleep efficiency, sleep timing midpoint, day‐to‐day sleep duration and sleep timing midpoint variability. Combined sleep duration and sleep timing behaviours were also derived (early‐bed/late‐rise, early‐bed/early‐rise, late‐bed/late‐rise, late‐bed/early‐rise). Outcomes included body mass index and BodPod‐assessed fat mass index, fasting serum leptin, C‐reactive protein, and homeostatic model assessment‐insulin resistance. Sleep duration was 5.4 h per night. We noted an inverse association between sleep duration and homeostatic model assessment‐insulin resistance. The early‐bed/early‐rise group had greater body mass index, C‐reactive protein and homeostatic model assessment‐insulin resistance compared with the early‐bed/late‐rise group (referent). Sex modified associations of sleep efficiency with C‐reactive protein; stratified results revealed positive association between sleep efficiency and C‐reactive protein in males, but not females. Race modified associations of sleep duration with body mass index and leptin, and of sleep duration variability with C‐reactive protein. Stratified analyses revealed inverse associations between sleep duration with body mass index and leptin in Black, multiracial/other race individuals only. Positive association between sleep duration variability and C‐reactive protein was noted in White individuals only. Shorter sleep duration, particularly when combined with earlier sleep timing, is associated with greater adiposity and serum cardiometabolic outcomes. Additional studies are needed to assess individual‐ and contextual‐level factors that may contribute to sex and race differences in sleep health and cardiometabolic risk in emerging adults

Physiologic synchrony: a systems approach to understanding the hierarchical regulation of physiologic function through the endocrine system following exercise

Alterations in the temporal organization and synchronous patterns among physio-logic systems have been detected across the spectrum of biological systems. These dy-namic relations between biomarkers provide important information about physiologic function. However, these patterns are not easily observed and difficult to characterize with traditional measures. There is a need to evolve existing approaches or develop and investigate new approaches that can provide knowledge about changes in the time-de-pendent regulatory behaviors of the physiologic system. The hypothalamic-pituitary axis is often considered the regulator of the endocrine system, receiving inputs from central and peripheral signals. Growth hormone (GH) is a pulsatile hormone secreted from the anterior pituitary largely regulated by somatotrophs of the hypothalamus, but it is also re-sponsive to feedback signals from the periphery. The secretory patterns of GH not only provide information about the dynamics of the hypothalamic-pituitary axis, but the state of the entire physiologic system; information that is unobserved by single-point measures and low sampling frequencies. Similarly, there is an abundance of information imbedded within the changes in the normal RR-intervals that is not observed through heart rate (HR) alone. Measures of HR variability (HRV) assess changes in the cardiac control that are representative of acute and chronic, physical, social, and psychophysio-logic stresses. The OBJECTIVE of this study was to investigate the dynamics of hypo-thalamic-pituitary regulation and cardiac control through GH, HRV, and additional bi-omarkers that share relationships with each of the associated pathways. METHODS: Eight healthy males (25.4±2.6 yrs, 174.7±7.8 cm) completed two 24-hr profiles at least 8 weeks apart (Exercise: 71.2±10.8 kg, 9.8±3.3 BF(%), VO2max 71.2±11.2 ml/kg/min and Rest: 69.8±12.1 kg, 9.0±2.7 BF(%), VO2max 67.8±9.0 ml/kg/min), where serum was col-lected every 10-min and RR-intervals were collected continuously. The order of the high-intensity exercise and resting- profiles were randomly assigned. The variability (standard deviation of the normal RR-interval—SDNNRR; standard deviation of the average of NN-intervals in all 5-min recordings across the 24-hr period—SDANN; root mean square of successive differences—rMSSDRR; low-frequency power—LF; high-frequency power—HF; and triangular index of the normal RR-intervals—TINN) and complexity (sample en-tropy—SampEnRR) of the 24-hr RR-records were assessed. In addition, the 24-hr RR-recordings were separated into 3-min epochs taken every 10 minutes—corresponding with the timing of the serum samples—and used to create additional time-series (HRVEP). The patterned regulation of cardiac control (SDNNEP, rMSSDEP, SampEnEP) throughout the day was assessed with recurrence analysis (RQA) and SampEn. Dynam-ics of paired profiles were compared using joint-entropy and cross-RQA (cRQA). Com-parisons between exercise and resting conditions were made using multivariate analysis of variance. Prediction models, using long-short-term-memory (LSTM) networks, were used to predict nighttime GH output based on the changes in cardiac control throughout the day. RESULTS: The optimal parameters chosen to analyze the dynamics of each profile were different (p=0.09) between exercise and resting conditions. Determinism (DET) of the GH profile interacted with changes in fitness between conditions (p=0.04). The LSTM networks performed accurately to predict GH output; these models performed better on exercise profiles compared to rest (p=0.02). CONCLUSIONS: Our findings suggest a common attractor among the hypothalamic-pituitary axis and cardiac control; assessed by GH and HRVEP respectively. Assessing the relations among these profiles in parallel may provide a method of creating a scalable model that can predict GH output from changes in HRVEP profiles. Reliable models that can predict these relationships may provide vital information about the system that could have astounding impacts within science and medicine. Integrating this diverse data into a single analytic environ-ment can help to provide researchers, clinicians, athletes, and patients the opportunity for earlier detection, easier assessment, more detailed monitoring, and increasingly ben-eficial treatment options. [This abstract has been edited to remove characters that will not display in this system. Please see the PDF for the full abstract.]]]> 2018 Hypothalamic-pituitary-thyroid axis Growth hormone releasing factor Heart rate monitoring English http://libres.uncg.edu/ir/uncg/f/Berry_uncg_0154D_12620.pdf oai:libres.uncg.edu/25137 2019-02-19T14:45:02Z UNCG Role of WNT5A isoform L(A) and isoform S(B) during osteoblast differentiation Bhandari, Dristi NC DOCKS at The University of North Carolina at Greensboro <![CDATA[WNT signaling has been characterized as a critical signaling cascade in many aspects of embryogenesis, cell differentiation and tissue homeostasis. Appropriate WNT signaling requires dynamic expression of WNTs along with their receptors, ensuring a proper balance between cell differentiation and proliferation. As a result, perturbation in WNT signaling by aberrant expression underlies various congenital malfunctions, cancer and other diseases. This study is focused on one family of WNT ligands called WNT5A. WNT5A plays a central role in primary axis formation and limb bud extension in development and has regulatory functions in mesenchymal cell differentiation, including bone formation. Moreover, WNT5A exhibits tumor suppressive as well as oncogenic properties in a wide range of cancers. Notably, the WNT5A gene encodes for two protein isoforms, isoform L(A) and isoform S(B). There is evidence that the isoforms are functionally distinct in cancer. However, there is a critical gap in understanding of the functional roles of the WNT5A isoforms in normal cell function. In this study, I investigated the functional contributions of the WNT5A isoforms during the process of normal osteoblast differentiation using the human fetal osteoblast cell line, hFOB1.19. The results show an increase in transcripts of both isoforms for normal differentiating osteoblasts. A trial examined for 21 days revealed that isoform L(A) and S(B) exhibit similar pattern during differentiation where both show gradual increase with progressing days. In addition, we identified an increase in expression of the WNT5A protein in hFOB1.19 cell line. The increase in isoform expression was correlated with molecular markers of osteoblast differentiation including RUNX2, osterix and osteocalcin and alkaline phosphatase (ALP) activity. Increasing the individual isoforms L(A) and S(B) in hFOB1.19 cells did not inhibit increases in RUNX2 and osteocalcin expression. Our results suggest a slight decrease in osteocalcin levels with treatment of L(A) and S(B)- conditioned medium (CM) on day 3 compared to the control. In contrast, RUNX2 was increased at day 2 and decreased at day 3 in isoform-CM treated cells. ALP activity decreased at day 7and 10 for both L(A)-CM and S(B)-CM treated cells, but only L(A)-CM showed a significant change at day 10. Next, I attempted to knockdown the individual isoforms and total WNT5A transcripts using siRNA techniques. Knockdown was achieved total WNT5A. Results show that by knocking down WNT5A, the early differentiation marker, RUNX2 decreases significantly by day 3 whereas the later differentiation marker, osteocalcin increases significantly by day 3. Taken together, these findings suggest that WNT5A isoform L(A) and S(B) appear to be involved in osteogenesis and the onset and increases of differentiation molecular markers show correlations with increases in the isoforms. However, as both WNT5A isoforms displayed similar patterns of expression during normal differentiation and after alteration of the individual isoform levels, a functional distinction between the isoforms during osteoblast differentiation cannot be asserted

The effects of low-intensity cycling on cognitive performance following sleep deprivation

This study examined the effect of 24 h of sleep deprivation on cognitive performance and assessed the effect of acute exercise on cognitive performance following sleep deprivation. Young, active, healthy adults (n = 24, 14 males) were randomized to control (age = 24.7 ± 3.7 years, BMI = 27.2 ± 7.0) or exercise (age = 25.3 ± 3.3 years, BMI = 25.6 ± 5.1) groups. Cognitive testing included a 5-min psychomotor vigilance task (PVT), three memory tasks with increasing cognitive load, and performance of the PVT a second time. On morning one, cognitive testing followed a typical night's sleep. Following 24-h of sustained wakefulness, cognitive testing was conducted again prior to and after the acute intervention. Participants in the exercise condition performed low-intensity cycling (~ 40%HRR) for 15-min and those in the control condition sat quietly on the bike for 15-min. t-Tests revealed sleep deprivation negatively affected performance on the PVT, but did not affect memory performance. Following the acute intervention, there were no cognitive performance differences between the exercise and rested conditions. We provide support for previous literature suggesting that during simple tasks, sleep deprivation has negative effects on cognitive performance. Importantly, in contrast to previous literature which has shown multiple bouts of exercise adding to cognitive detriment when combined with sleep deprivation, our results did not reveal any further detriments to cognitive performance from a single-bout of exercise following sleep deprivation

An external focus of attention is effective for balance control when sleep-deprived

The purpose of our study was to examine if the beneficial effects of an external focus are effective for balance control when sleep-deprived. Sleep-deprived participants (27 hours awake) completed three blocks of five separate 30 second trials on a dynamic balance board. All participants were given internal, external, and control instruction. For the internal focus trials, participants focused on their feet; whereas, for the external focus trials, participants focused on the balance board. Participants’ time in balance was significantly greater during the external focus compared to the internal focus and control. These findings suggest that external focus instructions are effective when participants are sleep-deprived

A molten salt test loop for component and instrumentation testing

Molten salt is an effective coolant for a wide range of applications, including nuclear reactors, concentrated solar power, and other high temperature industrial heat transfer processes. The technical readiness level of components and instrumentation for high-temperature molten salt applications needs improvement for molten salt to be more widely adopted. A molten salt test loop was designed, built, and commissioned as a test bed to address these issues. The molten salt test loop at Abilene Christian University was built out of 316 stainless steel with a forced flow centrifugal-type pump, and was instrumented for remote operation. A low-temperature molten nitrate salt was used in this system, which was designed to operate at temperatures up to 300 ◦C and flow rates up to 90 liters per minute. This paper describes the loop design, computational fluid dynamics modeling, construction, and commissioning details. An outline of the data acquisition and control systems is presented. Salt samples were taken before and after introduction into the loop, and melting points were measured both before and after salt circulation. Performance of the system is discussed as well as improvements required for higher temperature loops envisioned for the future

Mechanical Properties of Plant Underground Storage Organs and Implications for Dietary Models of Early Hominins

The diet of early human ancestors has received renewed theoretical interest since the discovery of elevated d13C values in the enamel of Australopithecus africanus and Paranthropus robustus. As a result, the hominin diet is hypothesized to have included C4 grass or the tissues of animals which themselves consumed C4 grass. On mechanical grounds, such a diet is incompatible with the dental morphology and dental microwear of early hominins. Most inferences, particularly for Paranthropus, favor a diet of hard or mechanically resistant foods. This discrepancy has invigorated the longstanding hypothesis that hominins consumed plant underground storage organs (USOs). Plant USOs are attractive candidate foods because many bulbous grasses and cormous sedges use C4 photosynthesis. Yet mechanical data for USOs—or any putative hominin food—are scarcely known. To fill this empirical void we measured the mechanical properties of USOs from 98 plant species from across sub-Saharan Africa. We found that rhizomes were the most resistant to deformation and fracture, followed by tubers, corms, and bulbs. An important result of this study is that corms exhibited low toughness values (mean = 265.0 J m-2) and relatively high Young’s modulus values (mean = 4.9 MPa). This combination of properties fits many descriptions of the hominin diet as consisting of hard-brittle objects. When compared to corms, bulbs are tougher (mean = 325.0 J m-2) and less stiff (mean = 2.5 MPa). Again, this combination of traits resembles dietary inferences, especially for Australopithecus, which is predicted to have consumed soft-tough foods. Lastly, we observed the roasting behavior of Hadza hunter-gatherers and measured the effects of roasting on the toughness on undomesticated tubers. Our results support assumptions that roasting lessens the work of mastication, and, by inference, the cost of digestion. Together these findings provide the first mechanical basis for discussing the adaptive advantages of roasting tubers and the plausibility of USOs in the diet of early hominins

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta