Publications by authors named "Nicholas Hedger"

Although exposure-based therapy has been found to be effective at alleviating symptoms of social anxiety disorder, it often does not lead to full remission, and relapse after treatment is common. Exposure therapy is based on theoretical principles of extinction of conditioned fear responses. However, there are inconsistencies in findings across experiments that have investigated the effect of social anxiety on threat conditioning and extinction processes.

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Quality control is a critical step in the processing and analysis of functional magnetic resonance imaging data. Its purpose is to remove problematic data that could otherwise lead to downstream errors in the analysis and reporting of results. The manual inspection of data can be a laborious and error-prone process that is susceptible to human error.

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One behaviour often observed in individuals with autism is that they tend to look less towards social stimuli relative to neurotypical individuals. For instance, many eye-tracking studies have shown that individuals with autism will look less towards people and more towards objects in scenes. However, we currently know very little about how these behaviours change over time.

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Social motivation accounts of autism spectrum disorder (ASD) posit that individuals with ASD find social stimuli less rewarding than neurotypical (NT) individuals. Behaviorally, this is proposed to manifest in reduced social orienting (individuals with ASD direct less attention towards social stimuli) and reduced social seeking (individuals with ASD invest less effort to receive social stimuli). In two meta-analyses, involving data from over 6000 participants, we review the available behavioral studies that assess social orienting and social seeking behaviors in ASD.

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Behavioral studies indicate that autistic traits predict reduced gaze toward social stimuli. Moreover, experiments that require participants to make an explicit choice between stimuli indicate reduced preferences for social stimuli in individuals with high autistic traits. These observations, in combination, fit with the idea that gaze is actively involved in the formation of choices-gaze toward a stimulus increases the likelihood of its subsequent selection.

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The visual probe (VP) paradigm provides evidence that emotional stimuli attract attention. Such effects have been reported even when stimuli are presented outside of awareness. These findings have shaped the idea that humans possess a processing pathway that detects evolutionarily significant signals independently of awareness.

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Individuals with low empathy often show reduced attention towards social stimuli. A limitation of this literature is the lack of empirical work that has explicitly characterized how this relationship manifests itself over time. We investigate this issue by analysing data from two large eye-tracking datasets (total n = 176).

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The motion aftereffect (MAE) provides a behavioural probe into the mechanisms underlying motion perception, and has been used to study the effects of attention on motion processing. Visual attention can enhance detection and discrimination of selected visual signals. However, the relationship between attention and motion processing remains contentious: not all studies find that attention increases MAEs.

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Given capacity limits, only a subset of stimuli give rise to a conscious percept. Neurocognitive models suggest that humans have evolved mechanisms that operate without awareness and prioritize threatening stimuli over neutral stimuli in subsequent perception. In this meta-analysis, we review evidence for this 'standard hypothesis' emanating from 3 widely used, but rather different experimental paradigms that have been used to manipulate awareness.

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Only a subset of visual signals give rise to a conscious percept. Threat signals, such as fearful faces, are particularly salient to human vision. Research suggests that fearful faces are evaluated without awareness and preferentially promoted to conscious perception.

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Background: Transcranial direct current stimulation (tDCS) is a potential alternative treatment option for major depressive episodes (MDE).

Objectives: We address the efficacy and safety of tDCS in MDE.

Methods: The outcome measures were Hedges' g for continuous depression ratings, and categorical response and remission rates.

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The rapid detection and evaluation of threat is of fundamental importance for survival. Theories suggest that this evolutionary pressure has driven functional adaptations in a specialized visual pathway that evaluates threat independently of conscious awareness. This is supported by evidence that threat-relevant stimuli rendered invisible by backward masking can induce physiological fear responses and modulate spatial attention.

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Threat-relevant stimuli such as fear faces are prioritized by the human visual system. Recent research suggests that this prioritization begins during unconscious processing: A specialized (possibly subcortical) pathway evaluates the threat relevance of visual input, resulting in preferential access to awareness for threat stimuli. Our data challenge this claim.

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