Faculty Bibliography

BACKGROUND:The obesity epidemic in the United States affects not only adults, but children and adolescents. SOURCES OF MATERIAL/UNASSIGNED:An extensive review of the literature including 85 articles has been completed with the aim of providing the most current definitions and recommendations for this chronic condition. ABSTACT OF FINDINGS/UNASSIGNED:This article reviews the definition of pediatric obesity, the increasing prevalence of obesity in children and adolescents, genetic and environmental risk factors, as well as the unique aspects and implications of this condition and its associated comorbidities for this population in comparison to adults. Current management recommendations are also discussed which include Intensive Health Behavioral and Lifestyle Treatment (IHBLT), metabolic surgery, and pharmacologic therapy including glucago-like peptide-1 receptor agonists (GLP-1RAs). CONCLUSION/CONCLUSIONS:Childhood obesity is a unique condition in its progression and management requirements, and should be approached with a focus on prevention as well as on the high-risk individual.

Precision-targeted ultrasonic neuromodulation offers immense potential for studying brain function and treating neurological diseases. Yet, its application has been limited by challenges in achieving precise spatio-temporal control and monitoring of ultrasound effects on brain circuits. Here we show that transcranial ultrasound elicits direct and highly focal responses, which can be dynamically steered at spatio-temporal scales relevant for neural function. Furthermore, holographic transcranial ultrasound stimulation allows direct control of the stimulated volume and actively modulates local and mid-range network projections, effectively lowering the activation threshold by an order of magnitude. To better understand this previously unexplored excitability regime not fully explained by the conventional pressure-frequency dyad, we developed a dual modelling framework, where both an empirical and a mechanistic model were constructed to capture the intricacies of holographic transcranial ultrasound stimulation. These models achieve qualitative agreement with our experimental results, suggesting that these findings are predominantly driven by putative network interactions. Our results bring insight on the complex interaction mechanisms of ultrasound with neural tissue and highlight its potential for the noninvasive interfacing of distributed brain networks.

INTRODUCTION/BACKGROUND:Affiliate stigma may cause depressive symptoms among Asian American dementia caregivers, yet few studies have examined the underlying mechanisms or cross-ethnic differences. METHODS:We analyzed data from 338 older dementia caregivers (176 Chinese Americans, 162 Korean Americans; mean age 68.8 years) who completed measures of affiliate stigma, social isolation, loneliness, and depressive symptoms. RESULTS:for interaction < 0.01). DISCUSSION/CONCLUSIONS:These findings identify affiliate stigma as an important risk factor for dementia caregivers' depressive symptoms, operating through both objective and emotional forms of social disconnection. Culturally sensitive efforts to reduce caregivers' stigma and social disconnection may improve mental health outcomes in Asian American communities.

Transcranial AC stimulation (tACS) of the cerebellum can entrain spiking activity in the Purkinje cells (PCs) of the cerebellar cortex and, through their projections, the cells in the cerebellar nuclei (CN). In this paper, we investigated if the cells in the motor thalamus (Mthal) can also be modulated (i.e. spikes entrained) via the CN-Mthal projections in rodents. A total of 82 thalamic cells were found, presumably in the Mthal by their stereotaxic coordinates, that were modulated by tACS of the cerebellum. Out of the 346 cells isolated, the thalamic cells with shorter action potentials and regular firing patterns had a higher probability of modulation by cerebellar stimulation than the cells with wider action potentials. The modulation level had a tuning curve with a maximum around 100-200 Hz. Spike histograms over the stimulation cycle transitioned between unimodal and bimodal distributions depending on the frequency. Most cells had a unimodal distribution at low frequencies, a bimodal distribution for frequencies between 80-125 Hz, and then a unimodal one for frequencies above 150 Hz. In addition, tACS of the motor cortex (MC) was also tested in a subset of thalamic cells. Unlike cerebellar stimulation, modulation levels peaked at two distinct frequencies, presumably due to entrainment through multiple MC-Mthal pathways with different preferred frequencies. The results demonstrate the feasibility of modulating a deep brain structure such as the thalamus through multi-synaptic pathways by stimulation of the cerebellar cortex (and the motor cortex) using a non-invasive neuromodulation method.

The autonomic nervous system (ANS) plays a vital role in health care for both acute care and chronic diseases. The traditional view of the ANS is to divide it into individual organ systems and study the separate components with a reductionist approach, which has been proven insufficient. Here, we argue that a holistic network-level view of the ANS is critical for generating new insights and deepening our understanding of its complex and dynamic functions. In this review, we treat the ANS as such a coordinated and dynamic network. We advocate for studying its interactions with major organ systems and the central nervous system using continuous and longitudinal monitoring in ambulatory and at-home settings rather than clinic-based snapshots. We first briefly review ANS physiology, then outline our network perspective, and finally highlight cutting-edge research directions and emerging engineering innovations in ANS monitoring, modeling, and modulation that benefit from this network-level view.

BACKGROUND:Familial dysautonomia (FD) is a hereditary neurodevelopmental disorder caused by aberrant splicing of the ELP1 gene, leading to a tissue-specific reduction in ELP1 protein expression. Preclinical models indicate that increasing ELP1 levels can mitigate disease manifestations. A blood-based ELP-1 protein assay may provide a reliable way to monitor gene target engagement. DESIGN AND METHODS/METHODS:Using a newly developed radioimmunoassay, we quantified ELP1 protein levels in peripheral blood samples collected from 59 homozygous FD patients carrying the IVS20 + 6T>C mutation and 66 heterozygous carriers. To assess the reproducibility of the measurement, replicate samples were collected in 43 participants. Longitudinal variability was evaluated in 22 participants who underwent repeat sampling 1 year later. RESULTS: = 0.827, p < 0.001). An ELP1 threshold of 492 pg/mL yielded a sensitivity of 80.2% (CI of 70.6 to 87.2%) and a specificity of 98.2% (95% CI of 90%-99%) with a positive likelihood ratio of 46.5, indicating that individuals with FD were over 46 times more likely to have ELP1 levels below this threshold compared to non-affected carriers. CONCLUSION/CONCLUSIONS:Blood ELP1 levels are robust and reproducible, with concentrations below 492 pg/mL strongly indicative of disease. Moreover, given their longitudinal stability, ELP1 can serve as a marker of target engagement to evaluate the efficacy of gene-targeted therapies aimed at correcting ELP1 gene splicing and protein production.

Aging is often accompanied by a decline in mobility across species, which can be improved by aerobic exercise, even in individuals with Parkinson's disease. We showed previously that 30 days of voluntary wheel-running exercise in young male mice leads to enhanced release of the motor-system transmitter, dopamine (DA), in ex vivo corticostriatal slices. Here we tested whether voluntary exercise also increases DA release in aging (12 months old) mice of both sexes, and whether this is associated with improved motor performance. Mice were allowed unlimited access to a rotating (runners) or a locked (controls) wheel for 30 days. Motor behavior was then assessed, and electrically evoked DA release was quantified in slices from these animals using fast-scan cyclic voltammetry. Although daily running distance for females was nearly twice that of males, runners of both sexes showed comparable increases in evoked DA release in dorsolateral striatum and in nucleus accumbens core and shell compared to age- and sex-matched controls. Runners of both sexes showed an increase in locomotion velocity and improved motor coordination. Thus, voluntary exercise boosts striatal DA release and improves motor performance in aging mice, providing new insights into the benefits of exercise in aging humans.

Seventy % of mammals copulate using repeated pelvic thrusting, while the transfer of sperm requires just a single intromission. Why did thrusting evolve to be the dominant form of sexual intercourse? In this study, we investigate how the rate of sexual pelvic thrusting changes with body size. By analyzing films of copulating mammals, from mice Mus musculus to elephants Elephantidae, we find that bigger animals thrust slower. The rate of pelvic thrusting decreases from 6 Hz for the pocket mouse Pergonathus to 1.3-1.8 Hz for humans to an absence of thrusting for the rhino Rhinocerotidae and elephant Elephantidae families. To understand this dependence on body size, we consider the spring-like behavior of the legs, which is associated with the elasticity of the body's muscles, tendons, and ligaments. For both running and thrusting, a maximum amplitude and great energy savings can be achieved if the system is oscillated at its resonant or natural frequency. Resonant frequencies, as measured through previous studies of running in dogs Canis familiaris and horses Equus ferus caballus, show good agreement with sexual thrusting frequencies. Running and sexual thrusting have nothing in common from a behavioral perspective, but from a physical perspective, they are both constrained by the same musculoskeletal systems, and both take advantage of resonance. Our findings may provide improved treatments for human sexual dysfunction as well as improving breeding strategies for domestic mammals.

Individuals with Alzheimer's disease (AD) have an increased incidence of seizures, which worsen cognitive decline. Using a transgenic mouse model of AD neuropathology that exhibits spontaneous seizures, we previously found that seizure activity stimulates and accelerates depletion of the hippocampal neural stem cell (NSC) pool, which was associated with deficits in neurogenesis-dependent spatial discrimination. However, the precise molecular mechanisms that drive seizure-induced activation and depletion of NSCs are unclear. Here, using mice of both sexes, we performed RNA-sequencing on the hippocampal dentate gyrus and identified differentially-expressed regulators of neurogenesis in the Wnt signaling pathway that regulates many aspects of cell proliferation. We found that the expression of sFRP3, a Wnt signaling inhibitor, is altered in a seizure-dependent manner and might be regulated by ΔFosB, a seizure-induced transcription factor. Increasing sFRP3 expression prevented NSC depletion and improved spatial discrimination, suggesting that the loss of sFRP3 might mediate seizure-driven impairment in cognition in AD model mice, and perhaps also in AD.Significance statement There is increased incidence of seizures in individuals with Alzheimer's disease (AD), but it is unclear how seizures contribute to cognitive decline. Here, we uncover a molecular mechanism by which seizures in AD induce expression of a long-lasting transcription factor in the hippocampal dentate gyrus that suppresses expression of sFRP3, an inhibitor of neural stem cell division, accelerating the depletion of a finite pool of neural stem cells and dysregulating adult hippocampal neurogenesis. We found that restoring sFRP3 expression prevents accelerated use and depletion of neural stem cells and improves performance in an adult neurogenesis-dependent cognitive task. Our findings have implications for AD, epilepsy, and other neurological disorders that are accompanied by seizures.