The role of specific central amygdala neurons in emotionally-triggered cataplexy

Narcolepsy is a neurological disorder characterized by a person’s inability to regulate sleep-wake cycles. Excessive daytime sleepiness and cataplexy are prominent symptoms of narcolepsy. Cataplexy is partial to full body muscle atonia usually brought on by the person with narcolepsy experiencing a positive emotion. Some features of cataplexy resemble those of REM sleep, including similar brain activity and muscle atonia. The neuronal circuit that produces cataplexy has yet to be determined. The similarities between REM sleep and cataplexy support the hypothesis that cataplexy is the result of the REM atonia pathways being activated. An emotion processing region, the central amygdala (CeA), projects to known REM regulatory regions and plays a role in cataplexy. GABAergic neurons of the CeA are sufficient and necessary to trigger cataplexy in mice and project to brainstem regions that regulate muscle tone. Cataplexy is often triggered in a social setting, such as when seeing an old friend or telling a joke. Oxytocin (OT) is involved in many social behaviors, making it a viable link between social stimuli and cataplexy. We hypothesized that oxytocin receptor (OTR) neurons of the CeA, a sub-population of GABAergic neurons, promote emotionally-triggered cataplexy. To determine the social phenotype of the narcolepsy mouse model, the orexin knock-out (OXKO) mouse, we used established behavioral assays of social interaction and social memory. To determine if social reunification influenced the amount of cataplexy, group-housed OXKO mice were isolated for a short time and reunited with their littermates. To determine if OTR neurons of the CeA were sufficient and necessary to promote socially-triggered cataplexy, we used chemogenetic technology known as Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) to selectively activate or inhibit these neurons. We injected adeno-associated viral vectors coding for either the excitatory hM3 Cre-dependent DREADD or the inhibitory hM4 Cre-dependent DREADD into the CeA of orexin knock-out mice crossed with OTR-Cre mice, allowing for expression of the DREADD exclusively in the OTR neurons of the CeA. After injection with either saline or clozapine-N-oxide (CNO) we put the mice through a behavioral assay to see if emotionally-triggered cataplexy increased or decreased following the activation or inhibition of OTR neurons of the CeA. The behavioral assays showed that acute social interactions in OXKO is normal, however they do have a social memory impairment. In addition, reunification promotes cataplexy in most OXKO mice. With the chemogenetic experiments, our number of mice is too low to report if OTR neurons of the CeA are sufficient and/or necessary for cataplexy at this time.2020-07-03T00:00:00

Australian medical students’ and junior doctors' perceptions of gender discrepancies in obstetrics and gynaecology

Background: There is currently a gender imbalance 85:15 female/male in the intake into specialist training for the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG). Aims: To determine the views and perceptions of Australian medical students, and junior doctors in the first five years of practice, toward obstetrics and gynaecology (O&G) as a career, including whether there are any perceived barriers to the pursuit of such a career. Materials and Methods: A semi-structured questionnaire was developed with members of the RANZCOG Gender Equity and Diversity Working Group There were two separate studies: the first involved telephone interviews of medical students across three campuses of a medical school in North Queensland. The second study surveyed junior doctors in Queensland who are members of the Australian Medical Association. Responses were analysed and compared using quantitative and qualitative methods. Results: Both studies found that experiences with O&G as a medical student influenced the decision to pursue O&G as a career. Exclusion from clinical scenarios and difficulty establishing good relationship with midwives within busy birthing suites were some reasons deterring male students from O&G. In addition, students felt poorly informed about the specialty in their preclinical years, affecting their early decisions in choice of specialty. Post-rotation, more female than male students reported positive experiences and were considering O&G as a career. Conclusions: Both groups see medical student experience as critical in attitudes toward the specialty as a possible career. This experience plays a significant role in encouraging female students toward a career in O&G and discouraging male students. More exposure to the specialty in the preclinical years, and attention to improving clinical rotations for all students, is required

Victim evaluations of face-to-face restorative justice conferences: A quasi-experimental analysis

One major goal of face-to-face restorative justice (RJ) is to help heal the psychological harm suffered by crime victims (Braithwaite, 2002). Substantial evidence from randomized controlled trials (RCTs) has shown that this can be accomplished (Strang, 2002) and more trials are underway (Sherman & Strang, 2004). These outcomes are even more clearly, if less rigorously, demonstrated through retrospective interviews of victims about their feelings before and after RJ took place. We review the responses of victims (N = 210) who participated in trials in Canberra (Australia) and in London, Thames Valley, and Northumbria (UK). Despite substantial variations in offense types, social contexts, nation and race, before-after changes revealed by qualitative and quantitative data are all in the same beneficial direction

Localized Heating Near a Rigid Spherical Inclusion in a Viscoelastic Binder Material Under Compressional Plane Wave Excitation

High-frequency mechanical excitation has been shown to generate heat within composite energetic materials and even induce reactions in single energetic crystals embedded within an elastic binder. To further the understanding of how wave scattering effects attributable to the presence of an energetic crystal can result in concentrated heating near the inclusion, an analytical model is developed. The stress and displacement solutions associated with the scattering of compressional plane waves by a spherical obstacle (Pao and Mow, 1963, “Scattering of Plane Compressional Waves by a Spherical Obstacle,” J. Appl. Phys., 34(3), pp. 493–499) are modified to account for the viscoelastic effects of the lossy media surrounding the inclusion (Gaunaurd and Uberall, 1978, “Theory of Resonant Scattering From Spherical Cavities in Elastic and Viscoelastic Media,” J. Acoust. Soc. Am., 63(6), pp. 1699–1712). The results from this solution are then utilized to estimate the spatial heat generation due to the harmonic straining of the material, and the temperature field of the system is predicted for a given duration of time. It is shown that for certain excitation and sample configurations, the elicited thermal response near the inclusion may approach, or even exceed, the decomposition temperatures of various energetic materials. Although this prediction indicates that viscoelastic heating of the binder may initiate decomposition of the crystal even in the absence of defects such as initial voids or debonding between the crystal and binder, the thermal response resulting from this bulk heating phenomenon may be a precursor to dynamic events associated with such crystal-scale effects

Decoupling of monsoon activity across the northern and southern Indo-Pacific during the Late Glacial

© The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Quaternary Science Reviews 176 (2017): 101-105, doi:10.1016/j.quascirev.2017.09.014.Recent studies of stalagmites from the Southern Hemisphere tropics of Indonesia revealed two shifts in monsoon activity not apparent in records from the Northern Hemisphere sectors of the Austral-Asian monsoon system: an interval of enhanced rainfall at ~19 ka, immediately prior to Heinrich Stadial 1, and a sharp increase in precipitation at ~9 ka. Determining whether these events are site-specific or regional is important for understanding the full range of sensitivities of the Austral-Asian monsoon. We present a discontinuous 40 kyr carbon isotope record of stalagmites from two caves in the Kimberley region of the north-central Australian tropics. Heinrich stadials are represented by pronounced negative carbon isotopic anomalies, indicative of enhanced rainfall associated with a southward shift of the intertropical convergence zone and consistent with hydroclimatic changes observed across Asia and the Indo- Pacific. Between 20-8 ka, however, the Kimberley stalagmites, like the Indonesian record, reveal decoupling of monsoon behavior from Southeast Asia, including the early deglacial wet period (which we term the Late Glacial Pluvial) and the abrupt strengthening of early Holocene monsoon rainfall.Funded by grants from the U.S. National Science Foundation Paleo Perspectives on Climate Change program (AGS-1103413 and AGS-1502917 to RFD) and AGS-1602455 (to CCU and RFD), the Center for Global and Regional Environmental Research, and Cornell College (to RFD). CCU acknowledges support from The Investment in Science Fund given primarily by WHOI Trustee and Corporation Members. Support also received from the Kimberley Foundation Australia

CHANGES IN BALANCE AND JOINT POSITION SENSE DURING A 12-DAY HIGH ALTITUDE TREK

The purpose of this study was to investigate changes in postural control and knee joint position sense (KJPS) during a trek to high altitude. Postural control during standing balance and KJPS were measured in 12 participants at sea-level, 3619m, 4600m and 5140m. Total (p = 0.003, d=1.9) and anterior-posterior sway velocity (p= 0.001, d=1.9) during standing balance with eyes open velocity was significantly greater at altitudes of 3619m and 5140m when compared with sea level. Despite a gradual ascent profile, exposure to 3619 m was associated with impairments in postural control. Importantly, these impairments did not worsen at higher altitudes. The present findings should be considered during future trekking expeditions when considering specific strategies to manage impairments in postural control that occur with increasing altitude