Tonic and phasic effects of reward on the pupil:implications for locus coeruleus function

The locus coeruleus (LC), a nucleus in the pons of the brainstem, plays a significant role in attention and cognitive control. Here, we use an adapted auditory oddball paradigm and measured the pupil dilation response, to provide a marker of LC activity in humans. In Experiment 1, we show event-related pupil responses to rare auditory events which were further elevated by task relevant. In Experiment 2, by asking participants to silently count the number of oddballs, we demonstrated that the task-relevance elevation was not a result of the generation or execution of the manual response. In Experiment 3, we observed two separate effects of reward on the pupil response. First, we found an overall increase in pupil area in the high compared to the low-reward blocks: a sustained effect reminiscent of the tonic changes that occur in LC. Second, we found elevated event-related pupil responses to behaviourally relevant stimuli in the high-reward condition compared with the low-reward condition, consistent with phasic changes in LC in response to a stimulus. These results highlight the complexity of the relationship between the pupil response and reward, and the inferred role of LC in both top-down and bottom-up cognitive control

Visual stress and dyslexia for the practicing optometrist

Visual stress should not be confused with dyslexia. It refers to symptoms of discomfort and perceptual distortion that have a neurological origin. Pattern 2 of the Pattern Glare Test can be used to elicit symptoms of visual stress, but pattern 3 is of relatively little clinical use. The symptoms sometimes remit with tints, but studies consistently show that tinting precision well within 0.07 in the CIE 1976 UCS diagram is necessary for optimal effect (see Precision is necessary – strong evidence is now available, below).  An improvement in reading speed with filters (overlays or lenses) can be measured using the Wilkins Rate of Reading Test, and an increase in reading speed of 15% is likely to indicate an improvement that exceeds any due to random variation. Visual stress remains a controversial issue, partly because of the publicity surrounding untrialled methods and partly because of reviews that are partial

Miniaturized data loggers and computer programming improve seabird risk and damage assessments for marine oil spills in Atlantic Canada

Obtaining useful information on marine birds that can aid in oil spill (and other hydrocarbon release) risk and damage assessments in offshore environments is challenging. Technological innovations in miniaturization have allowed archival data loggers to be deployed successfully on marine birds vulnerable to hydrocarbons on water. A number of species, including murres (both Common, Uria aalge, and Thick-billed, U. lomvia) have been tracked using geolocation devices in eastern Canada, increasing our knowledge of the seasonality and colony-specific nature of their susceptibility to oil on water in offshore hydrocarbon production areas and major shipping lanes. Archival data tags are starting to resolve questions around behaviour of vulnerable seabirds at small spatial scales relevant to oil spill impact modelling, specifically to determine the duration and frequency at which birds fly at sea. Advances in data capture methods using voice activated software have eased the burden on seabird observers who are collecting increasingly more detailed information on seabirds during ship-board and aerial transects. Computer programs that integrate seabird density and bird behaviour have been constructed, all with a goal of creating more credible seabird oil spill risk and damage assessments. In this paper, we discuss how each of these technological and computing innovations can help define critical inputs into seabird risk and damage assessments, and when combined, can provide a more realistic understanding of the impacts to seabirds from any hydrocarbon release

Neurophysiological signatures of Alzheimer's disease and frontotemporal lobar degeneration : pathology versus phenotype

The disruption of brain networks is characteristic of neurodegenerative dementias. However, it is controversial whether changes in connectivity reflect only the functional anatomy of disease, with selective vulnerability of brain networks, or the specific neurophysiological consequences of different neuropathologies within brain networks. We proposed that the oscillatory dynamics of cortical circuits reflect the tuning of local neural interactions, such that different pathologies are selective in their impact on the frequency spectrum of oscillations, whereas clinical syndromes reflect the anatomical distribution of pathology and physiological change. To test this hypothesis, we used magnetoencephalography from five patient groups, representing dissociated pathological subtypes and distributions across frontal, parietal and temporal lobes: amnestic Alzheimer's disease, posterior cortical atrophy, and three syndromes associated with frontotemporal lobar degeneration. We measured effective connectivity with graph theory-based measures of local efficiency, using partial directed coherence between sensors. As expected, each disease caused large-scale changes of neurophysiological brain networks, with reductions in local efficiency compared to controls. Critically however, the frequency range of altered connectivity was consistent across clinical syndromes that shared a likely underlying pathology, whilst the localization of changes differed between clinical syndromes. Multivariate pattern analysis of the frequency-specific topographies of local efficiency separated the disorders from each other and from controls (accuracy 62% to 100%, according to the groups' differences in likely pathology and clinical syndrome). The data indicate that magnetoencephalography has the potential to reveal specific changes in neurophysiology resulting from neurodegenerative disease. Our findings confirm that while clinical syndromes have characteristic anatomical patterns of abnormal connectivity that may be identified with other methods like structural brain imaging, the different mechanisms of neurodegeneration also cause characteristic spectral signatures of physiological coupling that are not accessible with structural imaging nor confounded by the neurovascular signalling of functional MRI. We suggest that these spectral characteristics of altered connectivity are the result of differential disruption of neuronal microstructure and synaptic physiology by Alzheimer's disease versus frontotemporal lobar degeneration.Peer reviewe

Raleigh youth well-being, Wake County : an action-oriented community diagnosis : findings and next steps of action

The Wake County Mental Health Association (MHA) is a the local affiliate of the National Mental Health Association (NMHA), an organization that works to improve the mental health of all Americans, especially the 54 million individuals with mental disorders, through advocacy, education, research and service. The Wake County MHA invited a team of six students from the UNC School of Public Health in Chapel Hill, NC to conduct an Action-Oriented Community Diagnosis (AOCD) to investigate the underlying factors that contribute to the well-being of middle school students in Raleigh. This approach was chosen to meet the needs of a broad range of stakeholders with an interest in the well-being of middle school youth in Raleigh—for example, while the MHA was interested in gaining insight into mental wellness services and programs desired by students and parents, our team also investigated the broader challenges related to general youth well being (i.e., parent-teen communication and peer pressure), in order to inform the efforts of a more diverse range of community organizations in Raleigh. The goal of an AOCD project is to investigate the strengths and challenges of a particular community by immersing oneself in the community and by speaking with key informants both inside the community (i.e., parents and students) and outside, yet linked to the community (i.e., service providers). The AOCD process culminates with a community forum in which community members and service providers discuss the project findings in order to develop action steps which address challenges. The forum also provides the team a formal venue in which to turn ownership of the project over to the community. Accordingly, with support and guidance from two MHA-affiliated community preceptors and a teaching team comprised of UNC faculty, our team entered the middle school community in October 2004, and held a community forum at Carnage Middle School in April 2005. Our team identified the strengths and challenges of middle school students by conducting interviews and focus groups with three sets of key informants—service providers, parents, and middle school students. Overall the team conducted a total of 18 interviews and 9 focus groups, making contact with a total of 60 individuals. Following a thorough review and comprehensive analysis of all interview transcripts, our team identified 13 key strengths and challenges of middle school students in Raleigh. Community members and service providers on a planning committee narrowed those themes down to the six issues they viewed as most important and most changeable. These included (1) mentoring and positive role models, (2) engaging in after school programs, (3) positive and negative peer pressure, (4) communication between teens and adults, (5) access to information about sex, and (6) parental involvement. Guided by a community-based planning committee, our team organized a community forum entitled “Celebrating the Middle School Community,” held on April 26th from 5:30 – 8:00 pm at Carnage Middle School in southeast Raleigh. Sixty-eight community members and service providers attended the forum. Following the introduction of the AOCD process and findings, attendees joined small group discussions surrounding each theme, which generated action steps for future initiatives. The main body of this document identifies all action steps and related discussion in great detail. This AOCD document is intended to serve as a resource to stakeholders in Raleigh’s middle school community, including students, parents, and service providers. It is our team’s hope that the resources presented within will contribute to the existing knowledge that impacts the well being of middle school youth, through both formal and informal structures in the community. It has been the team’s privilege to interact with so many impressive youth, parents, and service providers in Raleigh, and to observe first hand their commitment and passion for promoting environments in which youth can thrive through the middle school years. We hope that those who are interested in addressing some of the challenges that impede youth well being will find this document a useful starting point and a catalyst for new action.Master of Public Healt

The feasibility of delivering the ADVANCE digital intervention to reduce intimate partner abuse by men receiving substance use treatment:protocol for a non-randomised multi-centre feasibility study and embedded process evaluation

BACKGROUND: Compared to men in the general population, men in substance use treatment are more likely to perpetrate intimate partner abuse (IPA). The ADVANCE group intervention for men in substance use treatment is tailored to address substance use and IPA in an integrated way. In a feasibility trial pre-COVID, men who received the ADVANCE intervention via face-to-face group delivery showed reductions in IPA perpetration. Due to COVID-19, ADVANCE was adapted for remote digital delivery. METHODS/DESIGN: This mixed-methods non-randomised feasibility study, with a nested process evaluation, will explore the feasibility and acceptability of delivering the ADVANCE digital intervention to men in substance use treatment who have perpetrated IPA towards a female partner in the past year. Sixty men will be recruited from seven substance use treatment services in Great Britain. The ADVANCE digital intervention comprises a preparatory one-to-one session with a facilitator to set goals, develop a personal safety plan, and increase motivation and a preparatory online group to prepare men for taking part in the intervention. The core intervention comprises six fortnightly online group sessions and 12 weekly self-directed website sessions to recap and practise skills learned in the online group sessions. Each website session is followed by a one-to-one video/phone coaching session with a facilitator. Men will also receive their usual substance use treatment. Men’s female (ex) partners will be invited to provide outcome data and offered support from integrated safety services (ISS). Outcome measures for men and women will be sought post intervention (approximately 4 months post male baseline interview). Feasibility parameters to be estimated include eligibility, suitability, consent, recruitment, attendance, retention and follow-up rates. In-depth interviews or focus groups will explore the intervention’s acceptability to participants, facilitators and ISS workers. A secondary focus of the study will estimate pre-post-differences in outcome measures covering substance use, IPA, mental health, self-management, health and social care service use, criminal justice contacts and quality of life. DISCUSSION: Findings will inform the design of a multicentre randomised controlled trial evaluating the efficacy and cost-effectiveness of the ADVANCE digital intervention for reducing IPA. TRIAL REGISTRATION: The feasibility study was prospectively registered: ISRCTN66619273

Patients’ Experiences of a Sarcoma Diagnosis: A Process Mapping Exercise of Diagnostic Pathways

Patients with sarcoma often report prolonged time to diagnosis, which is attributed to the rarity of sarcoma and the low awareness of pre-diagnostic signs and symptoms. Aims: To describe patients’ experiences of pre-diagnostic signs/symptoms and pathways to diagnosis, including where help was sought, and the processes involved. Methods: Mixed methods involving quantitative, qualitative and inductive thematic analyses using novel process mapping of patient journey data, as reported by the patients. We examined the time from symptom onset to first professional presentation (patient interval, PI), first consultation to diagnostic biopsy, first consultation to diagnosis (diagnostic interval) and first presentation to diagnosis (total interval). Results: A total of 87 interviews were conducted over 5 months in 2017. Of these, 78 (40 males/38 females) were included. The sarcoma subtypes were bone (n = 21), soft tissue (n = 41), head and neck (n = 9) and gastro-intestinal (GIST; n = 7). Age at diagnosis was 13–24 (n = 7), 25–39 (n = 23), 40–64 (n = 34) and 65+ (n = 14) years. The median PI was 13 days (1–4971) and similar between sarcoma subtypes, with the exception of GIST (mPI = 2 days, (1–60). The longest mPI (31 days, range 4–762) was for those aged 13–24 years. The median diagnostic interval was 87.5 (range 0–5474 days). A total of 21 patients were misdiagnosed prior to diagnosis and symptoms were commonly attributed to lifestyle factors. Conclusions: Prolonged times to diagnosis were experienced by the majority of patients in our sample. Further research into the evolution of pre-diagnostic sarcoma symptoms is required to inform awareness interventions

Quaternary structure of a G-protein coupled receptor heterotetramer in complex with Gi and Gs

Background: G-protein-coupled receptors (GPCRs), in the form of monomers or homodimers that bind heterotrimeric G proteins, are fundamental in the transfer of extracellular stimuli to intracellular signaling pathways. Different GPCRs may also interact to form heteromers that are novel signaling units. Despite the exponential growth in the number of solved GPCR crystal structures, the structural properties of heteromers remain unknown. Results: We used single-particle tracking experiments in cells expressing functional adenosine A1-A2A receptors fused to fluorescent proteins to show the loss of Brownian movement of the A1 receptor in the presence of the A2A receptor, and a preponderance of cell surface 2:2 receptor heteromers (dimer of dimers). Using computer modeling, aided by bioluminescence resonance energy transfer assays to monitor receptor homomerization and heteromerization and G-protein coupling, we predict the interacting interfaces and propose a quaternary structure of the GPCR tetramer in complex with two G proteins. Conclusions: The combination of results points to a molecular architecture formed by a rhombus-shaped heterotetramer, which is bound to two different interacting heterotrimeric G proteins (Gi and Gs). These novel results constitute an important advance in understanding the molecular intricacies involved in GPCR function

Different decision deficits impair response inhibition in progressive supranuclear palsy and Parkinson's disease

Progressive supranuclear palsy and Parkinson’s disease have distinct underlying neuropathology, but both diseases affect cognitive function in addition to causing a movement disorder. They impair response inhibition and may lead to impulsivity, which can occur even in the presence of profound akinesia and rigidity. The current study examined the mechanisms of cognitive impairments underlying disinhibition, using horizontal saccadic latencies that obviate the impact of limb slowness on executing response decisions. Nineteen patients with clinically diagnosed progressive supranuclear palsy (Richardson’s syndrome), 24 patients with clinically diagnosed Parkinson’s disease and 26 healthy control subjects completed a saccadic Go/No-Go task with a head-mounted infrared saccadometer. Participants were cued on each trial to make a pro-saccade to a horizontal target or withhold their responses. Both patient groups had impaired behavioural performance, with more commission errors than controls. Mean saccadic latencies were similar between all three groups. We analysed behavioural responses as a binary decision between Go and No-Go choices. By using Bayesian parameter estimation, we fitted a hierarchical drift–diffusion model to individual participants’ single trial data. The model decomposes saccadic latencies into parameters for the decision process: decision boundary, drift rate of accumulation, decision bias, and non-decision time. In a leave-one-out three-way classification analysis, the model parameters provided better discrimination between patients and controls than raw behavioural measures. Furthermore, the model revealed disease-specific deficits in the Go/No-Go decision process. Both patient groups had slower drift rate of accumulation, and shorter non-decision time than controls. But patients with progressive supranuclear palsy were strongly biased towards a pro-saccade decision boundary compared to Parkinson’s patients and controls. This indicates a prepotency of responding in combination with a reduction in further accumulation of evidence, which provides a parsimonious explanation for the apparently paradoxical combination of disinhibition and severe akinesia. The combination of the well-tolerated oculomotor paradigm and the sensitivity of the model-based analysis provides a valuable approach for interrogating decision-making processes in neurodegenerative disorders. The mechanistic differences underlying participants’ poor performance were not observable from classical analysis of behavioural data, but were clearly revealed by modelling. These differences provide a rational basis on which to develop and assess new therapeutic strategies for cognition and behaviour in these disorders

Correlative multi-scale cryo-imaging unveils SARS-CoV-2 assembly and egress.

Funder: Medical Research CouncilSince the outbreak of the SARS-CoV-2 pandemic, there have been intense structural studies on purified viral components and inactivated viruses. However, structural and ultrastructural evidence on how the SARS-CoV-2 infection progresses in the native cellular context is scarce, and there is a lack of comprehensive knowledge on the SARS-CoV-2 replicative cycle. To correlate cytopathic events induced by SARS-CoV-2 with virus replication processes in frozen-hydrated cells, we established a unique multi-modal, multi-scale cryo-correlative platform to image SARS-CoV-2 infection in Vero cells. This platform combines serial cryoFIB/SEM volume imaging and soft X-ray cryo-tomography with cell lamellae-based cryo-electron tomography (cryoET) and subtomogram averaging. Here we report critical SARS-CoV-2 structural events - e.g. viral RNA transport portals, virus assembly intermediates, virus egress pathway, and native virus spike structures, in the context of whole-cell volumes revealing drastic cytppathic changes. This integrated approach allows a holistic view of SARS-CoV-2 infection, from the whole cell to individual molecules