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Neurons coordinate their activity to produce an astonishing variety of motor behaviors. Our present understanding of motor control has grown rapidly thanks to new methods for recording and analyzing populations of many individual neurons over time. In contrast, current methods for recording the nervous system’s actual motor output – the activation of muscle fibers by motor neurons – typically cannot detect the individual electrical events produced by muscle fibers during natural behaviors and scale poorly across species and muscle groups. Here we present a novel class of electrode devices (‘Myomatrix arrays’) that record muscle activity at unprecedented resolution across muscles and behaviors. High-density, flexible electrode arrays allow for stable recordings from the muscle fibers activated by a single motor neuron, called a ‘motor unit,’ during natural behaviors in many species, including mice, rats, primates, songbirds, frogs, and insects. This technology therefore allows the nervous system’s motor output to be monitored in unprecedented detail during complex behaviors across species and muscle morphologies. We anticipate that this technology will allow rapid advances in understanding the neural control of behavior and identifying pathologies of the motor system.

Abstract Humans exhibit changes in postural control when confronted with threats to stability. This study used a prolonged threat exposure protocol to manipulate emotional state within a threatening context to determine if any threat-induced standing behaviours are employed independent of emotional state. Retention of balance adaptations was also explored. Thirty-seven adults completed a series of 90-s standing trials at two surface heights (LOW: 0.8 m above ground, away from edge; HIGH: 3.2 m above ground, at edge) on two visits 2–4 weeks apart. Psychological and autonomic state was assessed using self-report and electrodermal measures. Balance control was assessed using centre of pressure (COP) and lower limb electromyographic recordings. Upon initial threat exposure, individuals leaned backward, reduced low-frequency centre of pressure (COP) power, and increased high-frequency COP power and plantar/dorsiflexor coactivation. Following repeated exposure, the psychological and autonomic response to threat was substantially reduced, yet only high-frequency COP power and plantar/dorsiflexor coactivation habituated. Upon re-exposure after 2–4 weeks, there was partial recovery of the emotional response to threat and few standing balance adaptations were retained. This study suggests that some threat-induced standing behaviours are coupled with the psychological and autonomic state changes induced by threat, while others may reflect context-appropriate adaptations resistant to habituation.

American Indian and Alaska Native (AI/AN) youth are strong in culture and rich in heritage and experience unique strengths and challenges throughout adolescence. Documenting conditions that protect against risk factors associated with poor health outcomes are needed. We explored scales that measure self-esteem, culture, social support, and community from a sample of 1,456 youth involved in Native STAND, a culturally-relevant evidence-based sexual health intervention. We established content validity by reviewing existing literature and community feedback. Construct validity was examined using factor analysis. The final self-esteem model included seven items, factor loadings ranged from 0.47 to 0.63 for positive self-esteem and 0.77 to 0.81 for negative self-esteem. The final culture model included three items, factor loadings 0.73 to 0.89. The social support scale included four items, factor loadings ranged from 0.86 to 0.87 for family social support and 0.75 to 0.77 for friends social support. The community and community safety scale included three items; factor loadings ranged from 0.52 to 0.82. Coefficient alphas for scales ranged from α = 0.63 to α = 0.86. This study validated scales in a national sample of AI/AN youth-psychometric scales provide an essential tool for documenting the needs and strengths of AI/AN youth.

Abstract Height-induced postural threat influences standing balance control. However, it is unknown if minimizing individuals’ emotional response to threat moderates this relationship. This study repeatedly exposed individuals to height-induced postural threat to determine if reducing the emotional response to threat influences standing balance control. Sixty-eight young adults completed a series of standing trials at LOW (0.8 m above ground, away from edge) and HIGH (3.2 m above ground, at edge) postural threat conditions. Emotional state was assessed using self-report and electrodermal measures. Standing balance was assessed through analysis of centre of pressure (COP) movement and lower leg electromyographic activity. Individuals’ emotional response to threat was attenuated following repeated threat exposure. However, threat-induced changes in standing balance were largely preserved. When initially threatened, individuals leaned backward and demonstrated smaller amplitude and higher frequency of COP adjustments; these balance outcomes did not change following repeated threat exposure. Only high frequency COP oscillations (>1.8 Hz) and ankle muscle co-contraction showed any adaptation; regression analyses showed that these behavioural adaptations were accounted for by a combination of emotional and cognitive state changes. This suggests that some threat-induced standing balance changes are more closely linked with the emotional response to threat than others, and are therefore amendable to intervention.

In the United States, there is no reliable data to describe the prevalence of eye diseases leading to visual impairment and little active surveillance to address this knowledge gap. Data that is readily available from many state blind registries may provide helpful information on trends and causes of blindness. We analyzed new registrations with the Oregon Commission for the Blind (OCB) and Oregon State Department of Administrative Services (DAS) from 1961 to 2016 for causes of and trends in blindness. Persons with blindness self-refer into the OCB registry and the Oregon State Department of Administrative Services (DAS) includes those receiving social security disability financial support and other state services. Data for 9,273 blind persons registered were analyzed. The most frequent causes of blindness were age related macular degeneration (AMD) 3,308 (38%), followed by diabetic retinopathy (DR) 729 (8%), congenital conditions 697 (8%), optic nerve atrophy 611 (7%), glaucoma 549 (6%), retinitis pigmentosa 546 (6%), retinopathy of prematurity192 (2%), cataract 180 (2%), and trauma 174 (2%). The mean age of onset of blindness was younger for Blacks (31 years) and Hispanics (33 years) than for Whites (44 years). Analysis of state-based registries can provide useful and locally relevant vision and eye health data where little information is otherwise available.

Purpose: Barriers to health care present complex challenges to improving eye health in the U.S., yet few studies have quantitatively measured the impact of these barriers. This study investigated the time elapsed since a person’s most recent eye examination (TLEE) as a measure of barriers to eye care. Methods: Participants (N = 1699) from mobile clinic vision health screenings completed demographic and subjective visual function questionnaires, and then underwent comprehensive eye exams. Associations between demographics, subjective visual function, and visual acuity were analyzed with respect to TLEE. Results: Many Hispanic (34.9%) and uninsured (28.6%) participants had no previous eye exam. Although most Caucasians had a previous eye exam, 40.2% did not have an exam in the previous four years. The majority of participants with diabetes were non-compliant with recommendations of annual eye examinations. Conclusion: These results describe barriers that are specific to subpopulations, providing useful information for efforts to improve eye care access.

In the U.S., the prevalence of blindness is expected to double by 2050 and as many half of those with blinding eye disease are unaware of their diagnosis. Screening for vision health in the community setting may offer a key strategy to address the rising trend avoidable vision loss. However, problems with excessive referrals and low compliance with these referrals (often