Fixation instruction influences gaze cueing

Studies have shown that perceiving another person's gaze shift facilitates responses in the direction of the perceived gaze shift. While it is often assumed that participants in these experiments remain fixated on the cue in the cueing interval, eye gaze is not always recorded to confirm this. The data presented here suggest that the effect of gaze cues on responses to peripheral targets depends on whether participants make eye movements prior to the onset of the target. Participants who were required to fixate showed cueing effects at short cue-target intervals, but no cueing at later intervals. Participants who could look around, often chose to do so, and showed the same positive cueing effects at the shorter interval, but negative cueing effects (suggestive of inhibition of return) at the longer interval

A Feasibility Study in Measuring Soft Tissue Artifacts on the Upper Leg Using Inertial and Magnetic Sensors

Soft-tissue artifacts cause inaccurate estimates of body segment orientations. The inertial sensor (or optical marker) is orientating (or displacing) with respect to the bone it has to measure, due to muscle and skin movement [1]. In this pilot study 11 inertial and magnetic sensors (MTw, Xsens Technologies) were placed on the rectus femoris, vastus medialis and vastus lateralis (upper leg). One sensor was positioned on the tendon plate behind the quadriceps (iliotibial tract, as used in Xsens MVN [1]) and used as reference sensor. Walking, active and passive knee extensions and muscle contractions without flexion/extension were recorded using one subject. The orientation of each sensor with respect to the reference sensor was calculated. During walking, relative orientations of up to 28.6º were measured (22.4±3.6º). During muscle contractions without flexion/extension the largest relative orientations were measured on the rectus femoris (up to 11.1º) [2]. This pilot showed that the ambulatory measurement of deformation of the upper leg is feasible; however, improving the measurement technology is required. We therefore have designed a new inertial and magnetic sensor system containing smaller sensors, based on the design of an instrumented glove for the assessment of hand kinematics [3]. This new sensor system will then be used to investigate soft-tissue artifacts more accurately; in particular we will focus on in-use estimation and elimination of these artifacts

Alcohol use in bipolar disorder: A neurobiological model to help predict susceptibility, select treatments and attenuate cortical insult.

In a series of neurophysiological and neuroimaging studies we investigated the neurobiology related to alcohol use in young people with bipolar disorder. Impairments were identified across frontal and temporal representations of event-related potential and proton magnetic resonance spectroscopy markers; mismatch negativity and in vivo glutathione, respectively. We propose these findings reflect impairments in the N-methyl-D-aspartate receptor and antioxidant capacity. This review seeks to place these findings within the broader literature in the context of two propositions: 1. Pathophysiological impairments in N-methyl-D-aspartate receptor functioning in bipolar disorder contribute to susceptibility toward developing alcohol problems. 2. Alcohol aggravates bipolar disorder neuroprogression via oxidative stress. A neurobiological model that incorporates these propositions is presented, with a focus on the potential for N-methyl-D-aspartate receptor antagonism and glutathione augmentation as potential adjunctive pharmacotherapies to treat the comorbidity. While this review highlights the importance of alcohol monitoring and reduction strategies in the treatment of bipolar disorder, the clinical impact of the proposed model remains limited by the lack of controlled trials of novel pharmacological interventions.NHMRC Australia Fellowship 46491

Gaze and arrow distractors influence saccade trajectories similarly

Perceiving someone's averted eye-gaze is thought to result in an automatic shift of attention and in the preparation of an oculomotor response in the direction of perceived gaze. Although gaze cues have been regarded as being special in this respect, recent studies have found evidence for automatic attention shifts with nonsocial stimuli, such as arrow cues. Here, we directly compared the effects of social and nonsocial cues on eye movement preparation by examining the modulation of saccade trajectories made in the presence of eye-gaze, arrows, or peripheral distractors. At a short stimulus onset asynchrony (SOA) between the distractor and the target, saccades deviated towards the direction of centrally presented arrow distractors, but away from the peripheral distractors. No significant trajectory deviations were found for gaze distractors. At the longer SOA, saccades deviated away from the direction of the distractor for all three distractor types, but deviations were smaller for the centrally presented gaze and arrow distractors. These effects were independent of whether line-drawings or photos of faces were used and could not be explained by differences in the spatial properties of the peripheral distractor. The results suggest that all three types of distractors (gaze, arrow, peripheral) can induce the automatic programming of an eye movement. Moreover, the findings suggest that gaze and arrow distractors affect oculomotor preparation similarly, whereas peripheral distractors, which are classically regarded as eliciting an automatic shift of attention and an oculomotor response, induce a stronger and faster acting influence on response preparation and the corresponding inhibition of that response

Hippocampal glutamatergic/NMDA receptor functioning in bipolar disorder: a combined MMN and 1H-MRS study

Disturbances in the hippocampal glutamate (Glu)/N-methyl-d-aspartate (NMDA) system have been implicated in the pathophysiology of bipolar disorder (BD). Here we aim to provide a targeted integration of two measures of glutamatergic functioning in BD; the association between mismatch negativity (MMN) and in vivo hippocampal-Glu measured via proton magnetic resonance spectroscopy ((1)H MRS). Participants comprised of 33 patients with BD and 23 matched controls who underwent a two-tone passive, duration deviant MMN paradigm and (1)H MRS. Levels of Glu/creatine (Cr) in the hippocampus were determined. Pearson's correlations were used to determine associations between MMN and Glu/Cr. In controls, MMN amplitude was positively associated with Glu/Cr at the left temporal site. We did not find any significant associations with Glu/Cr and frontocentral MMN nor did we find any significant associations in BD patients. The results provide further insight into the neurophysiology of MMN, with evidence supporting the role of hippocampal-Glu signalling through the NMDA receptor in temporal MMN. Our data also demonstrate that Glu/Cr regulation of MMN is dampened in BD, which may indicate a lack of tightly regulated hippocampal NMDA functioning. These findings provide insight into the underlying basis of glutamatergic transmission disturbances implicated in the disorder.NHMRC Australia Fellowship 46491

A longitudinal proton magnetic resonance spectroscopy study investigating oxidative stress as a result of alcohol and tobacco use in youth with bipolar disorder

Alcohol and tobacco have been suggested to be "aggravating factors" for neuroprogression in bipolar disorder (BD), however the impact of these substances on the underlying neurobiology is limited. Oxidative stress is a key target for research into neuroprogression in BD and in accordance with this model, our previous cross-sectional studies have found that risky alcohol and tobacco use in BD is associated with increased oxidative stress, investigated via in vivo glutathione (GSH) measured by proton magnetic resonance spectroscopy ((1)H-MRS) in the anterior cingulate cortex (ACC). What remains unknown is whether the negative impact on GSH levels can be modified as a result of limiting alcohol and tobacco use. Thirty BD patients were included in the study. (1)H-MRS and tobacco and alcohol measures were conducted at baseline and follow-up assessments (15.5±4.6 months apart). Pearson׳s correlations were performed between percentage change in GSH concentration and changes in alcohol/tobacco use. Regression analyses were then conducted to further explore the significant correlations. An increase in GSH was associated with a decrease in alcohol consumption (r=-0.381, p<0.05) and frequency of tobacco use (-0.367, p=0.05). Change in alcohol consumption, tobacco use and age were significant predictors of change in GSH concentration (F (3, 26)=3.69, p<0.05). Due to the high comorbidity of alcohol and tobacco use in the sample, the individual effects of these substances on GSH levels could not be determined. This study offers longitudinal evidence that changing risky drinking patterns and tobacco use early in the course of BD is associated with improvements in antioxidant capacity, and therefore may be specific targets for early intervention and prevention of neuroprogression in BD.NHMRC Australia Fellowship 46491

Video Assisted Thoracoscopic Treatment of Pleuropericardial Cysts

Question of the Study In this study, safety and feasibility of thoracoscopic fenestration of pleuropericardial cysts under local and general anaesthesia is evaluated. Besides, a rare case of a pleural cyst, causing a superior vena cava syndrome, is described

Insomnia symptoms and short sleep duration predict trajectory of mental health symptoms

Objectives: We evaluated whether insomnia symptoms and short or long sleep duration, alone or in combination, are robustly associated with subsequent trajectory of mental health symptoms. Methods: Participants were 2598 individuals (15 to 94 years of age) with elevated mental health symptoms at baseline (2013-14). Associations of baseline insomnia symptoms and sleep duration with two-year trajectory of mental health were estimated and adjusted for multiple potential confounders. Outcomes included recovery (well at both follow-up timepoints), intermittent symptoms (unwell at one follow-up timepoint), and chronic symptoms (unwell at each follow-up timepoint). Results: Adjusted for age and sex, baseline insomnia symptoms predicted intermittent (OR 1.43, 95% CI 1.15-1.80) and chronic (OR 2.16, 95% CI 1.77-2.68) trajectories of mental health symptoms. Short sleep duration (= 6 to Conclusion: A focus on just sleep duration or insomnia symptoms in those with elevated mental health symptoms will not be adequate to address chronicity. Both components of sleep disturbance, and in particular their co-occurrence, should be addressed. (c) 2018 Elsevier B.V. All rights reserved.Peer reviewe

What is the prevalence, and what are the clinical correlates, of insulin resistance in young people presenting for mental health care? A cross-sectional study

Objectives: To report the distribution and predictors of insulin resistance (IR) in young people presenting to primary care-based mental health services. Design: Cross-sectional. Setting: Headspace-linked clinics operated by the Brain and Mind Centre of the University of Sydney. Participants: 768 young people (66% female, mean age 19.7±3.5, range 12–30 years). Main outcome measures: IR was estimated using the updated homeostatic model assessment (HOMA2-IR). Height and weight were collected from direct measurement or self-report for body mass index (BMI). Results: For BMI, 20.6% of the cohort were overweight and 10.2% were obese. However,6.9 mmol/L). By contrast, 9.9% had a HOMA2-IR score \u3e2.0 (suggesting development of IR) and 11.7% (n=90) had a score between 1.5 and 2. Further, there was a positive correlation between BMI and HOMA2-IR (r=0.44, p Conclusions: Emerging IR is evident in a significant subgroup of young people presenting to primary care based mental health services. While the major modifiable risk factor is BMI, a large proportion of the variance is not accounted for by other demographic, clinical or treatment factors. Given the early emergence of IR, secondary prevention interventions may need to commence prior to the development of full-threshold or major mood or psychotic disorders