Sociopolitical crises causing uncertainty have accumulated in recent years, providing fertile ground for the emergence of conspiracy ideations. Computational models constitute valuable tools for understanding the mechanisms at play in the formation and rigidification of these unshakeable beliefs. Here, the Circular Inference model was used to capture associations between changes in perceptual inference and the dynamics of conspiracy ideations in times of uncertainty.
View Article and Find Full Text PDFA body of research indicates that people are prone to overestimate the affective impact of future events. Here, we developed a novel experimental paradigm to study these affective forecasting biases under laboratory conditions using subjective (arousal and valence) and autonomic measures (skin conductance responses, SCRs, and heart rate). Thirty participants predicted their emotional responses to 15 unpleasant, 15 neutral, and 15 pleasant scenarios (affective forecasting phase) to which they were then exposed in virtual reality (emotional experience phase).
View Article and Find Full Text PDFBackground: Research on biased processing of aversive stimuli in posttraumatic stress disorder (PTSD) has produced inconsistent results between response time (RT) and eye-tracking studies. Recent RT-based results of dot-probe studies showed no attentional bias (AB) for threat while eye-tracking research suggested heightened sustained attention for this information. Here, we used both RT-based and eye-tracking measures to explore the dynamics of AB to negative stimuli in PTSD.
View Article and Find Full Text PDFRationale: Visuo-perceptive deficits in severe alcohol use disorder (SAUD) remain little understood, notably regarding the respective involvement of the two main human visual streams, i.e., magnocellular (MC) and parvocellular (PC) pathways, in these deficits.
View Article and Find Full Text PDFVisuospatial impairments have long been reported in Severe Alcohol Use Disorder but remain poorly understood, notably regarding the involvement of magnocellular (MC) and parvocellular (PC) pathways. This empirical gap hampers the understanding of the implications of these visual changes, especially since the MC and PC pathways are thought to sustain central bottom-up and top-down processes during cognitive processing. They thus influence our ability to efficiently monitor our environment and make the most effective decisions.
View Article and Find Full Text PDFBackground: One of the core features of posttraumatic stress disorder (PTSD) is re-experiencing trauma. The anterior insula (AI) has been proposed to play a crucial role in these intrusive experiences. However, the dynamic function of the AI in re-experiencing trauma and its putative modulation by effective therapy need to be specified.
View Article and Find Full Text PDFBackground: Functional magnetic resonance imaging (fMRI) capture aims at detecting auditory-verbal hallucinations (AVHs) from continuously recorded brain activity. Establishing efficient capture methods with low computational cost that easily generalize between patients remains a key objective in precision psychiatry. To address this issue, we developed a novel automatized fMRI-capture procedure for AVHs in patients with schizophrenia (SCZ).
View Article and Find Full Text PDFThis study aimed to investigate the time course of attentional bias for negative information in healthy individuals and to assess the associated influence of trait anxiety. Thirty-eight healthy volunteers performed an emotional dot-probe task with pairs of negative and neutral scenes, presented for either 1 or 2 s and followed by a target placed at the previous location of either negative or neutral stimulus. Analyses included eye movements during the presentation of the scenes and response times associated with target localization.
View Article and Find Full Text PDFWe investigated the relative contributions of central versus peripheral vision in scene-gist recognition with panoramic 180° scenes. Experiment 1 used the window/scotoma paradigm of Larson and Loschky (2009). We replicated their findings that peripheral vision was more important for rapid scene categorization, while central vision was more efficient, but those effects were greatly magnified.
View Article and Find Full Text PDFInvest Ophthalmol Vis Sci
October 2018
Purpose: To measure the distance for sex and facial expression recognition in patients with glaucoma.
Methods: Sixteen patients with open-angle glaucoma, 16 age-matched controls, and 12 young controls participated. During each trial, a face covering 0.
Aim: Object/background association is critical to understand the context of visual scenes but also in daily life tasks like object search. Patients with Alzheimer disease (AD) exhibit impairment in scene processing at different levels: perception, recognition, memory and spatial navigation. We explored whether patients with AD make use of contextual information in congruent and incongruent target/background conditions in three different saccadic choice tasks.
View Article and Find Full Text PDFSignificance: Vision is paramount for motor actions directed toward objects. Vision allows not only the identification of objects and their shape and spatial location, but also the adaptation of our movement when it arrives on the object. These findings show that vision deficits, as in age-related macular degeneration (AMD), can lead to reaching and grasping deficits.
View Article and Find Full Text PDFBackground: This study investigated whether realistic immersive conditions with dynamic indoor scenes presented on a large, hemispheric panoramic screen covering 180° of the visual field improved the visual search abilities of participants with age-related macular degeneration (AMD).
Method: Twenty-one participants with AMD, 16 age-matched controls and 16 young observers were included. Realistic indoor scenes were presented on a panoramic five metre diameter screen.
Patients with Parkinson's disease have better functional status and motor performance under on-drug conditions. However, the administration of levodopa leads to greater postural sway. The present study's primary objective was to determine whether this on-drug problem may be related to a lack of adjustment in postural control mechanisms and body segment rotations.
View Article and Find Full Text PDFIn studies of postural control, a control task is often used to understand significant effects obtained with experimental manipulations. This task should be the easiest task and (therefore) engage the lowest behavioral variability and cognitive workload. Since 1983, the stationary-gaze task is considered as the most relevant control task.
View Article and Find Full Text PDFThe pathophysiology of visual hallucinations in Parkinson's disease has yet to be characterized. Although stimulus-driven ("bottom-up") processes are known to be impaired, the role of "top-down" processes remains to be determined. Distinguishing between conscious and non-conscious detections (i.
View Article and Find Full Text PDFPrevious works usually report greater postural stability in precise visual tasks (e.g., gaze-shift tasks) than in stationary-gaze tasks.
View Article and Find Full Text PDFPurpose: We investigated the visuomotor behavior of people with reduced peripheral field due to glaucoma while they accomplished natural actions.
Methods: Twelve participants with glaucoma and 13 normally sighted controls were included. Participants were asked to accomplish a familiar sandwich-making task and a less familiar model-building task with a children's construction set while their eye movements were recorded.
We investigated explicit and implicit emotional processing in peripheral vision using saccadic choice tasks. Emotional-neutral pairs of scenes were presented peripherally either at 10, 30 or 60° away from fixation. The participants had to make a saccadic eye movement to the target scene: emotional vs neutral in the explicit task, and oval vs rectangular in the implicit task.
View Article and Find Full Text PDFNeuroimaging studies have shown that faces exhibit a central visual field bias, as compared to buildings and scenes. With a saccadic choice task, Crouzet, Kirchner, and Thorpe (2010) demonstrated a speed advantage for the detection of faces with stimuli located 8° from fixation. We used the same paradigm to examine whether the face advantage, relative to other categories (animals and vehicles), extends across the whole visual field (from 10° to 80° eccentricity) or whether it is limited to the central visual field.
View Article and Find Full Text PDFInvest Ophthalmol Vis Sci
October 2015
Purpose: To use eye movements to investigate how people with a central scotoma might be impaired in the execution of natural actions and whether task familiarity affects performance.
Methods: Sixteen participants with AMD and 16 age-matched controls performed two natural actions: (1) a familiar sandwich-making task and (2) a less familiar model-building task. In each action, task-relevant and task-irrelevant objects were placed on a table, covering 90°.
Purpose: In our modern society, many touch screen applications require hand-eye coordination to associate an icon with its specific contextual unit on phones, on computers, or in public transport. We assessed the ability of patients with age-related macular degeneration (AMD) to explore scenes and to associate a target (animal or object) with a unique congruent scene (e.g.
View Article and Find Full Text PDFWe assessed the effects of donepezil, a drug that stimulates cholinergic transmission, and scopolamine, an antagonist of cholinergic transmission, on contrast sensitivity. 30 young male participants were tested under three treatment conditions: placebo, donepezil, and scopolamine in a random order. Pairs of photographs varying in contrast were displayed left and right of fixation for 50 ms.
View Article and Find Full Text PDFDement Geriatr Cogn Dis Extra
March 2015
Aims: We investigated the performance in scene categorization of patients with Alzheimer's disease (AD) using a saccadic choice task.
Method: 24 patients with mild AD, 28 age-matched controls and 26 young people participated in the study. The participants were presented pairs of coloured photographs and were asked to make a saccadic eye movement to the picture corresponding to the target scene (natural vs.