David Western

Dr. David Western

orcid

Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
9 November 2011 in Psychological Medicine
Verified
Journal Article
Closed access
PDF file
MSMartina Di Simplicio
Martina Di Simplicio
GCG. Costoloni
G. Costoloni
DWDavid Western
David Western
BHB. Hanson
B. Hanson
PTP. Taggart
P. Taggart
CHC. J. Harmer
C. J. Harmer
Background: Dysfunctions in the regulation of emotional responses are related to poor psychological well-being and increased impact of cardiovascular disease. It has been suggested that the relationship between negative affect and higher morbidity could be mediated by a dysregulation of the autonomic nervous system (ANS), for example, of heart rate variability (HRV). Neuroticism is a personality trait associated with a maladaptive emotion regulation and also with alterations in ANS function. However, it is unknown whether subjects with high neuroticism present with specific biases in emotion regulation associated with reduced HRV.Method: In total, 33 healthy subjects (n=13, highly neurotic) performed an emotion regulation task, during which they were instructed to either passively view negative pictures or attempt to down-regulate the affect elicited by the images. During the task an electrocardiogram was recorded and HRV was measured by calculation of the high frequency spectrum (HF-HRV).Results: A significant interaction between task condition and personality group was observed on HF-HRV measures (F1,31=6.569, p=0.016). This was driven by subjects with low neuroticism presenting higher HF-HRV during down-regulation compared to passive exposure to negative stimuli, while subjects with high neuroticism reported an opposite tendency.Conclusions: Our results show reduced HF-HRV during cognitive reappraisal of negative stimuli in high neuroticism and indicate a specific link between loss of flexibility in the parasympathetic cardiovascular tone and emotion regulation, consistent with previous work. Such findings support the importance of exploring the combination of ANS adaptability and emotional dysregulation in neuroticism as different facets of a common psychosomatic vulnerability factor.

3 November 2015 in Translational Psychiatry
Verified
Journal Article
Open access
PDF file
ARA Reinecke
A Reinecke
NFNicola Filippini
Nicola Filippini
CBC Berna
C Berna
DWDavid Western
David Western
BHB Hanson
B Hanson
CHC J Harmer
C J Harmer
Impairments in emotion regulation are thought to have a key role in the pathogenesis of anxiety disorders, but the neurobiological underpinnings contributing to vulnerability remain poorly understood. It has been a long-held view that exaggerated fear is linked to hyperresponsivity of limbic brain areas and impaired recruitment of prefrontal control. However, increasing evidence suggests that prefrontal–cortical networks are hyperactive during threat processing in anxiety disorders. This study directly explored limbic–prefrontal neural response, connectivity and heart-rate variability (HRV) in patients with a severe anxiety disorder during incidental versus intentional emotion regulation. During 3 Tesla functional magnetic resonance imaging, 18 participants with panic disorder and 18 healthy controls performed an emotion regulation task. They either viewed negative images naturally (Maintain), or they were instructed to intentionally downregulate negative affect using previously taught strategies of cognitive reappraisal (Reappraisal). Electrocardiograms were recorded throughout to provide a functional measure of regulation and emotional processing. Compared with controls, patients showed increased neural activation in limbic–prefrontal areas and reduced HRV during incidental emotion regulation (Maintain). During intentional regulation (Reappraisal), group differences were significantly attenuated. These findings emphasize patients’ ability to regulate negative affect if provided with adaptive strategies. They also bring prefrontal hyperactivation forward as a potential mechanism of psychopathology in anxiety disorders. Although these results challenge models proposing impaired allocation of prefrontal resources as a key characteristic of anxiety disorders, they are in line with more recent neurobiological frameworks suggesting that prefrontal hyperactivation might reflect increased utilisation of maladaptive regulation strategies quintessential for anxiety disorders.

21 June 2016
Verified
Book Chapter
Open access
PDF file
DADejanira Araiza-Illan
Dejanira Araiza-Illan
DWDavid Western
David Western
APAnthony G. Pipe
Anthony G. Pipe
KEKerstin Eder
Kerstin Eder
Industries such as flexible manufacturing and home care will be transformed by the presence of robotic assistants. Assurance of safety and functional soundness for these robotic systems will require rigorous verification and validation. We propose testing in simulation using Coverage-Driven Verification (CDV) to guide the testing process in an automatic and systematic way. We use a two-tiered test generation approach, where abstract test sequences are computed first and then concretized (e.g., data and variables are instantiated), to reduce the complexity of the test generation problem. To demonstrate the effectiveness of our approach, we developed a testbench for robotic code, running in ROS-Gazebo, that implements an object handover as part of a human-robot interaction (HRI) task. Tests are generated to stimulate the robot’s code in a realistic manner, through stimulating the human, environment, sensors, and actuators in simulation. We compare the merits of unconstrained, constrained and model-based test generation in achieving thorough exploration of the code under test, and interesting combinations of human-robot interactions. Our results show that CDV combined with systematic test generation achieves a very high degree of automation in simulation-based verification of control code for robots in HRI.

1 June 2014 in Circulation: Arrhythmia and Electrophysiology
Verified
Journal Article
Closed access
PDF file
NCNicholas Child
Nicholas Child
BHBen Hanson
Ben Hanson
MBMartin Bishop
Martin Bishop
CRChristopher A. Rinaldi
Christopher A. Rinaldi
JBJulian Bostock
Julian Bostock
PTPeter Taggart
Peter Taggart
Background—Mental stress and emotion have long been associated with ventricular arrhythmias and sudden death in animal models and humans. The effect of mental challenge on ventricular action potent...

1 January 2012 in Frontiers in Physiology
Verified
Journal Article
Open access
PDF file
BHBen Hanson
Ben Hanson
JGJaswinder Gill
Jaswinder Gill
DWDavid Western
David Western
MGMichael P. Gilbey
Michael P. Gilbey
JBJulian Bostock
Julian Bostock
PTPeter Taggart
Peter Taggart
Background: Respiratory modulation of autonomic input to the sinus node results in cyclical modulation of heart rate, known as respiratory sinus arrhythmia (RSA). We hypothesized that the respiratory cycle may also exert cyclical modulation on ventricular repolarization, which may be separately measurable using local endocardial recordings. Methods and Results: The study included 16 subjects with normal ventricles undergoing routine clinical electrophysiological procedures for supraventricular arrhythmias. Unipolar electrograms were recorded from 10 right and 10 left ventricular endocardial sites. Breathing was voluntarily regulated at 5 fixed frequencies (6, 9, 12, 15, and 30 breaths per min) and heart rate was clamped by RV pacing. Activation-recovery intervals (ARI: a surrogate for APD) exhibited significant (p < 0.025) cyclical variation at the respiratory frequency in all subjects; ARI shortened with inspiration and lengthened with expiration. Peak-to-peak ARI variation ranged from 0–26 ms; the spatial pattern varied with subject. Arterial blood pressure also oscillated at the respiratory frequency (p < 0.025) and lagged behind respiration by between 1.5 s and 0.65 s from slowest to fastest breathing rates respectively. Systolic oscillation amplitude was significantly greater than diastolic (14 ± 5 vs. 8 ± 4 mm Hg ± SD, p < 0.001). Conclusions: Observations in humans with healthy ventricles using multiple left and right ventricular endocardial recordings showed that ARI action potential duration (APD) varied cyclically with respiration.

28 November 2015
Verified
Book Chapter
Closed access
PDF file
DADejanira Araiza-Illan
Dejanira Araiza-Illan
DWDavid Western
David Western
APAnthony Pipe
Anthony Pipe
KEKerstin Eder
Kerstin Eder