Assessing the relationship between corticospinal excitability and mechanical force generation to both arms during arm cycling: are asymmetries present?

Investigations regarding asymmetries in cortical motor control during static and locomotor movements has been conducted. From this research, interhemispheric asymmetries related to movement have been identified, where excitability of the dominant cerebral hemisphere is generally greater compared to the non-dominant. During locomotor outputs like cycling, bilateral asymmetries in measures such as crank torque, power, and/or work have been identified. However, the majority of studies examining human neural control during locomotor outputs is typically available only regarding the dominant limb. Currently, it is unknown how corticospinal excitability and mechanical force generation is modulated during a locomotor output, and whether asymmetries are present. Thus, the purpose of this study was to examine corticospinal and spinal excitability with vector force generation to the dominant and non-dominant biceps and triceps brachii during arm cycling to determine whether bilateral asymmetries were present

Recent trauma and acute infection as risk factors for childhood arterial ischemic stroke.

ObjectiveTrauma and acute infection have been associated with stroke in adults, and are prevalent exposures in children. We hypothesized that these environmental factors are independently associated with childhood arterial ischemic stroke (AIS).MethodsIn a case-control study nested within a cohort of 2.5 million children (≤19 years old) enrolled in an integrated health care plan (1993-2007), childhood AIS cases (n = 126) were identified from electronic records and confirmed through chart review. Age- and facility-matched controls (n = 378) were randomly selected from the cohort. Exposures were determined from review of medical records prior to the stroke diagnosis, or the same date for the paired controls; time windows were defined a priori.ResultsA medical encounter for head or neck trauma within the prior 12 weeks was an independent risk factor for childhood AIS (odds ratio [OR], 7.5; 95% confidence interval [CI], 2.9-19.3), present in 12% of cases (1.6% of controls). Median time from trauma to stroke was 0.5 days (interquartile range, 0-2 days); post hoc redefinition of trauma exposure (prior 1 week) was more strongly associated with AIS: OR, 39; 95% CI, 5.1-298. A medical encounter for a minor acute infection (prior 4 weeks) was also an independent risk factor (OR, 4.6; 95% CI, 2.6-8.2), present in 33% of cases (13% of controls). No single infection type predominated. Only 2 cases had exposure to trauma and infection.InterpretationTrauma and acute infection are common independent risk factors for childhood AIS, and may be targets for stroke prevention strategies

AI Without Math: Making AI and ML Comprehensible

If we want nontechnical stakeholders to respond to artificial intelligence developments in an informed way, we must help them acquire a more-than-superficial understanding of artificial intelligence (AI) and machine learning (ML). Explanations involving formal mathematical notation will not reach most people who need to make informed decisions about AI. We believe it is possible to teach many AI and ML concepts without slipping into mathematical notation

Ultrahigh-temperature granulite-facies metamorphism and exhumation of deep crust in a migmatite dome during late- to post-orogenic collapse and extension in the central Adirondack Highlands (New York, USA)

This study combines field observations, mineral and whole-rock geochemistry, phase equilibrium modeling, and U-Pb sensitive high-resolution ion microprobe (SHRIMP) zircon geochronology to investigate sillimanite-bearing felsic migmatites exposed on Ledge Mountain in the central Adirondack Highlands (New York, USA), part of an extensive belt of mid-crustal rocks comprising the hinterland of the Mesoproterozoic Grenville orogen. Phase equilibrium modeling suggests minimum peak metamorphic conditions of 960-1025 °C and 11-12.5 kbar during the Ottawan orogeny—sig-nificantly higher pressure-temperature conditions than previously determined—followed by a period of near-isothermal decompression, then isobaric cooling. Petrography reveals abundant melt-related microstructures, and pseudosection models show the presence of at least ~15%-30% melt during buoyancy-driven exhumation and decompression. New zircon data document late Ottawan (re)crys-tallization at ca. 1047 ± 5 to 1035 ± 2 Ma following ultrahigh-temperature (UHT) metamorphism and anatexis on the retrograde cooling path. Inherited zircon cores give a mean date of 1136 ± 5 Ma, which suggests derivation of these felsic granulites by partial melting of older igneous rocks. The ferroan, anhydrous character of the granulites is similar to that of the ca. 1050 Ma Lyon Mountain Granite and consistent with origin in a late- to post-Ottawan extensional environment. We present a model for development of a late Ottawan migmatitic gneiss dome in the central Adirondacks that exhumed deep crustal rocks including the Snowy Mountain and Oregon anorthosite massifs with UHT Ledge Mountain migmatites. Recognition of deep crustal meta-plutonic rocks recording UHT metamorphism in a migmatite gneiss dome has significant implications for crustal behavior in this formerly thickened orogen

The Effects of Equine-Assisted Therapy on Gait in Adults with Parkinson’s Disease: A Preliminary Analysis

Parkinson’s disease (PD) is a chronic, progressive, neurological disorder caused by the destruction of dopamine-producing neurons in the substantia nigra of the brain. To treat motor symptoms of PD, individuals may choose alternative modes of exercise, such as equine-assisted therapy (EAT), to improve physiological health. PURPOSE: To determine changes in gait following 8 weeks of Equine Assisted Therapy (EAT) in older men with PD. METHODS: Six older adults (age = 68.0 ± 8.6 yrs; height = 178.6 ± 8.3 cm; weight = 93.4 ± 16.3 kg; Hoehn and Yahr classification = 2.8 ± 0.4; time since diagnosis = 7.3 ± 5.0 yrs) performed two, 60-minute riding sessions weekly for 8 weeks. Before, midway, immediately after, and at two points following the EAT program (at 8 weeks and 16 weeks), spatiotemporal parameters of gait were measured using motion capture with infrared markers strategically placed on lower-body anatomical landmarks. Participants walked at a self-selected speed without the use of an assistive device in the capture space for 15 consecutive strides, turned around, and walked back across the space. Gait velocity, step length, time spent in stance phase, time spent in swing phase, toe clearance were collected. Data were analyzed using a repeated-measures analysis-of-variance and a Bonferroni correction with a significance level of 0.05. RESULTS: Gait velocity (101.8 ± 29.1 vs. 109.2 ± 34.9 vs. 116.3 ± 32.8 vs. 105.7 ± 26.2 vs. 108.0 ± 25.4 cm/s for pre-EAT, midway through EAT, immediately post-EAT, 8 weeks after EAT concluded, and 16 weeks after EAT concluded, respectively) was significant across all time points (p = 0.03). All other variables were statistically similar (p \u3e 0.05) across all time points. CONCLUSION: There is an observable trend towards significance in each gait variable immediately after 8 weeks of EAT. The study is ongoing and will further explore these differences

From Spinning Silk to Spreading Saliva: Mouthpart Remodeling in Manduca sexta (Lepidoptera: Sphingidae)

As a model organism, the tobacco hornworm Manduca sexta (Linnaeus 1763) has contributed much to our knowledge of developmental processes in insects, and major developmental changes between different larval instars are generally well understood. Second and later instars of M. sexta do not produce silk, and their spinneret and accessory labial glands (=Lyonet’s glands), structures thought to be key players in silk production in other lepidopterans, are highly reduced. To our knowledge, mouthparts and labial gland morphology of the silk-producing first instar have never been described. In this study, we compared the mouthpart morphology and transcriptome profile of first and later instars of M. sexta to determine whether the loss of silk production correlates with changes in the structure of the spinneret and the labial glands, and with changes in expression of silk-related genes. We found that the first instar, unlike later instars, has a typical, silk-producing spinneret with a tube-like spigot and well developed Lyonet’s glands. Moreover, three known silk protein genes are highly expressed in the first instar but exhibit little to no expression in the embryo or later instars. Thus, the changes in morphology and gene expression presented here, coinciding with changes in larval behavior from silk production to saliva spreading, further our understanding of the developmental processes underlying this transition in this model organism

A developmental framework linking neurogenesis and circuit formation in the Drosophila CNS.

The mechanisms specifying neuronal diversity are well characterized, yet it remains unclear how or if these mechanisms regulate neural circuit assembly. To address this, we mapped the developmental origin of 160 interneurons from seven bilateral neural progenitors (neuroblasts) and identify them in a synapse-scale TEM reconstruction of the Drosophila larval central nervous system. We find that lineages concurrently build the sensory and motor neuropils by generating sensory and motor hemilineages in a Notch-dependent manner. Neurons in a hemilineage share common synaptic targeting within the neuropil, which is further refined based on neuronal temporal identity. Connectome analysis shows that hemilineage-temporal cohorts share common connectivity. Finally, we show that proximity alone cannot explain the observed connectivity structure, suggesting hemilineage/temporal identity confers an added layer of specificity. Thus, we demonstrate that the mechanisms specifying neuronal diversity also govern circuit formation and function, and that these principles are broadly applicable throughout the nervous system