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ELife Jun 2024Autism spectrum disorder (ASD) presents a range of challenges, including heightened sensory sensitivities. Here, we examine the idea that sensory overload in ASD may be...
Autism spectrum disorder (ASD) presents a range of challenges, including heightened sensory sensitivities. Here, we examine the idea that sensory overload in ASD may be linked to issues with efference copy mechanisms, which predict the sensory outcomes of self-generated actions, such as eye movements. Efference copies play a vital role in maintaining visual and motor stability. Disrupted efference copies hinder precise predictions, leading to increased reliance on actual feedback and potential distortions in perceptions across eye movements. In our first experiment, we tested how well healthy individuals with varying levels of autistic traits updated their mental map after making eye movements. We found that those with more autistic traits had difficulty using information from their eye movements to update the spatial representation of their mental map, resulting in significant errors in object localization. In the second experiment, we looked at how participants perceived an object displacement after making eye movements. Using a trans-saccadic spatial updating task, we found that those with higher autism scores exhibited a greater bias, indicating under-compensation of eye movements and a failure to maintain spatial stability during saccades. Overall, our study underscores efference copy's vital role in visuo-motor stability, aligning with Bayesian theories of autism, potentially informing interventions for improved action-perception integration in autism.
Topics: Humans; Male; Female; Autism Spectrum Disorder; Adult; Young Adult; Eye Movements; Psychomotor Performance; Visual Perception; Adolescent; Saccades; Autistic Disorder
PubMed: 38913073
DOI: 10.7554/eLife.94946 -
Cureus May 2024Persistent postural-perceptual dizziness (PPPD) is a chronic and disabling disorder characterized by persistent dizziness, unsteadiness, and imbalance. It often arises... (Review)
Review
Persistent postural-perceptual dizziness (PPPD) is a chronic and disabling disorder characterized by persistent dizziness, unsteadiness, and imbalance. It often arises without an identifiable cause and is exacerbated by upright posture, active or passive movement, and exposure to moving or complex visual stimuli. This complex pathophysiology and the psychological dimensions of its symptomatology pose a significant challenge to clinicians. PPPD presents diagnostic challenges and a lack of standardized treatment options, underscoring the need for multidisciplinary approaches encompassing pharmacotherapy, vestibular rehabilitation, and psychological interventions for effective management. Bridging the gaps in understanding PPPD requires collaborative efforts across disciplines, emphasizing integrated research approaches and patient support networks to enhance care and improve outcomes. This review explores the challenges, controversies, and clinical complexities of PPPD, highlighting the importance of a patient-centered approach.
PubMed: 38910644
DOI: 10.7759/cureus.60911 -
BMC Psychology Jun 2024Fear overgeneralization constitutes a susceptibility factor contributing to the development and maintenance of anxiety spectrum disorders. Extant research has...
BACKGROUND
Fear overgeneralization constitutes a susceptibility factor contributing to the development and maintenance of anxiety spectrum disorders. Extant research has demonstrated that exposure to positive and supportive social relationships attenuates fear acquisition and promotes the extinction of conditioned fear responses. However, the literature lacks investigation into the effect of secure attachment priming on inhibiting the generalization of conditioned fear.
METHODS
In this study, college students were recruited via online platforms to voluntarily engage in the experimental procedures, resulting in 57 subjects whose data were deemed suitable for analysis. The experimental protocol consisted of four consecutive phases: pre-acquisition, acquisition, priming, and generalization. The priming phase consisted of two experimental conditions: secure attachment priming (experimental group) and positive emotion priming (control group). This study adopted the perceptual discrimination fear conditioning paradigm, employing subjective expectancy of shock ratings and skin conductance responses as primary assessment indices. Individual difference variables were measured using corresponding psychological measurement scales.
RESULTS
In terms of generalization degree, a notable divergence surfaced in the skin conductance responses across various generalization materials between the secure attachment priming group and the control group. Similarly, during generalization extinction, a significant disparity emerged in the skin conductance responses across different generalization phases between the secure attachment priming group and the control group. In addition, individual differences analyses revealed that the inhibitory effect of secure attachment priming on fear generalization was not affected by intolerance of uncertainty and attachment orientations. Conversely, slope analyses confirmed that as intolerance of uncertainty increased, the inhibitory effect of positive emotion priming on fear generalization was attenuated.
CONCLUSION
The findings suggest that activating participants' representations of secure attachment via imagination effectively attenuates the generalization of perceptual fear at the physiological level. The inhibitory effect of secure attachment priming appears to be distinct from positive emotional modulation and remains unaffected by individual trait attachment styles. These results offer novel insights and avenues for the prevention and clinical intervention of anxiety spectrum disorders.
Topics: Humans; Fear; Male; Female; Young Adult; Generalization, Psychological; Object Attachment; Adult; Conditioning, Classical; Galvanic Skin Response; Extinction, Psychological; Adolescent
PubMed: 38890761
DOI: 10.1186/s40359-024-01857-9 -
Scientific Reports Jun 2024Face-processing timing differences may underlie visual social attention differences between autistic and non-autistic people, and males and females. This study...
Face-processing timing differences may underlie visual social attention differences between autistic and non-autistic people, and males and females. This study investigates the timing of the effects of neurotype and sex on face-processing, and their dependence on age. We analysed EEG data during upright and inverted photographs of faces from 492 participants from the Longitudinal European Autism Project (141 neurotypical males, 76 neurotypical females, 202 autistic males, 73 autistic females; age 6-30 years). We detected timings of sex/diagnosis effects on event-related potential amplitudes at the posterior-temporal channel P8 with Bootstrapped Cluster-based Permutation Analysis and conducted Growth Curve Analysis (GCA) to investigate the timecourse and dependence on age of neural signals. The periods of influence of neurotype and sex overlapped but differed in onset (respectively, 260 and 310 ms post-stimulus), with sex effects lasting longer. GCA revealed a smaller and later amplitude peak in autistic female children compared to non-autistic female children; this difference decreased in adolescence and was not significant in adulthood. No age-dependent neurotype difference was significant in males. These findings indicate that sex and neurotype influence longer latency face processing and implicates cognitive rather than perceptual processing. Sex may have more overarching effects than neurotype on configural face processing.
Topics: Humans; Female; Male; Adolescent; Child; Adult; Autistic Disorder; Young Adult; Electroencephalography; Brain; Evoked Potentials; Facial Recognition; Sex Characteristics
PubMed: 38890406
DOI: 10.1038/s41598-024-64387-9 -
Proceedings. Biological Sciences Jun 2024Visual illusions have been studied in many non-human species, spanning a wide range of biological and methodological variables. While early reviews have proved useful in... (Meta-Analysis)
Meta-Analysis Review
Visual illusions have been studied in many non-human species, spanning a wide range of biological and methodological variables. While early reviews have proved useful in providing an overview of the field, they have not been accompanied by quantitative analysis to systematically evaluate the contribution of biological and methodological moderators on the proportion of illusory choice. In the current meta-analytical study, we confirm that geometrical visual illusion perception is a general phenomenon among non-human animals. Additionally, we found that studies testing birds report stronger illusion perception compared to other classes, as do those on animals with lateral-positioned eyes compared to animals with forward-facing eyes. In terms of methodological choices, we found a positive correlation between the number of trials during training or testing and the effect sizes, while studies with larger samples report smaller effect sizes. Despite studies that trained animals with artificial stimuli showing larger effect sizes compared with those using spontaneous testing with naturalistic stimuli, like food, we found more recent studies prefer spontaneous choice over training. We discuss the challenges and bottlenecks in this area of study, which, if addressed, could lead to more successful advances in the future.
Topics: Animals; Visual Perception; Optical Illusions; Illusions; Birds
PubMed: 38889782
DOI: 10.1098/rspb.2024.0414 -
Neuropsychiatric Disease and Treatment 2024Conventional methods like patient history, neuropsychological testing, cerebrospinal fluid examination, and magnetic resonance imaging are widely used to diagnose cases...
INTRODUCTION
Conventional methods like patient history, neuropsychological testing, cerebrospinal fluid examination, and magnetic resonance imaging are widely used to diagnose cases in the current clinical setting but are limited in classifying Alzheimer's disease (AD) stages. Patients with AD exhibit visual perception deficits, which may be a potential target to assess the severity of the disease according to visual paradigms. However, owing to the inconsistent forms of perceived objects, the defects of current visual processing paradigms often lead to inconsistent results and a lack of sensitivity and specificity.
METHODS
We develop two paradigms based on global-first topological approach of visual perception, which avoids inconsistent results and lack of sensitivity and specificity owing to the inconsistent forms of perceived objects in traditional paradigms, delineate a unique detection strategy from perception organization (Experiment 1) and visual working memory (VWM) (Experiment 2).
RESULTS
Except for the significant differences of the reaction times (RTs) between groups, significant differences were found when AD subjects recognize small figures due to the consistency of global and local figures in similarity test. The difference of RTs between recognizing global and local figures can be recognized in AD and mild cognitive impairment (MCI) group compared to healthy elderly (HE) in similarity test (Experiment 1). The memory capacity of AD patients was significantly lower than MCI group. Topological interference effect was observed in MCI and HE group, whereas MCI patients may have a greater difference trend in non-topological and topological changes than HE (Experiment 2).
CONCLUSION
Our paradigms provide a new strategy, which can assist clinical severity staging and linking topological approach of visual perception with pathophysiological processes in AD.
PubMed: 38883415
DOI: 10.2147/NDT.S460421 -
Comprehensive Psychiatry Aug 2024The link between trauma exposure and psychotic disorders is well-established. Further, specific types of trauma may be associated with specific psychotic symptoms....
BACKGROUND
The link between trauma exposure and psychotic disorders is well-established. Further, specific types of trauma may be associated with specific psychotic symptoms. Network analysis is an approach that can advance our understanding of the associations across trauma types and psychotic symptoms.
METHODS
We conducted a network analysis with data from 16,628 adult participants (mean age [standard deviation] = 36.3 years [11.5]; 55.8% males) with psychotic disorders in East Africa recruited between 2018 and 2023. We used the Life Events Checklist and the Mini International Neuropsychiatric Interview to determine whether specific trauma types experienced over the life course and specific psychotic symptoms were connected. We used an Ising model to estimate the network connections and bridge centrality statistics to identify nodes that may influence trauma types and psychotic symptoms.
RESULTS
The trauma type "exposure to a war zone" had the highest bridge strength, betweenness, and closeness. The psychotic symptom "odd or unusual beliefs" had the second highest bridge strength. Exposure to a war zone was directly connected to visual hallucinations, odd or unusual beliefs, passivity phenomena, and disorganized speech. Odd or unusual beliefs were directly connected to transportation accidents, physical assault, war, and witnessing sudden accidental death.
CONCLUSION
Specific trauma types and psychotic symptoms may interact bidirectionally. Screening for psychotic symptoms in patients with war-related trauma and evaluating lifetime trauma in patients with odd or unusual beliefs in clinical care may be considered points of intervention to limit stimulating additional psychotic symptoms and trauma exposure. This work reaffirms the importance of trauma-informed care for patients with psychotic disorders.
Topics: Humans; Psychotic Disorders; Adult; Male; Female; Middle Aged; Africa, Eastern; Psychological Trauma; Hallucinations
PubMed: 38876004
DOI: 10.1016/j.comppsych.2024.152504 -
Magnetic Resonance in Medical Sciences... Jun 2024Diffusion-weighted MRI (dMRI) provides a unique non-invasive view of human brain tissue properties. The present review article focuses on tractometry analysis methods...
Diffusion-weighted MRI (dMRI) provides a unique non-invasive view of human brain tissue properties. The present review article focuses on tractometry analysis methods that use dMRI to assess the properties of brain tissue within the long-range connections comprising brain networks. We focus specifically on the major white matter tracts that convey visual information. These connections are particularly important because vision provides rich information from the environment that supports a large range of daily life activities. Many of the diseases of the visual system are associated with advanced aging, and tractometry of the visual system is particularly important in the modern aging society. We provide an overview of the tractometry analysis pipeline, which includes a primer on dMRI data acquisition, voxelwise model fitting, tractography, recognition of white matter tracts, and calculation of tract tissue property profiles. We then review dMRI-based methods for analyzing visual white matter tracts: the optic nerve, optic tract, optic radiation, forceps major, and vertical occipital fasciculus. For each tract, we review background anatomical knowledge together with recent findings in tractometry studies on these tracts and their properties in relation to visual function and disease. Overall, we find that measurements of the brain's visual white matter are sensitive to a range of disorders and correlate with perceptual abilities. We highlight new and promising analysis methods, as well as some of the current barriers to progress toward integration of these methods into clinical practice. These barriers, such as variability in measurements between protocols and instruments, are targets for future development.
PubMed: 38866532
DOI: 10.2463/mrms.rev.2024-0007 -
PLoS Biology Jun 2024Despite the diverse genetic origins of autism spectrum disorders (ASDs), affected individuals share strikingly similar and correlated behavioural traits that include...
Shared behavioural impairments in visual perception and place avoidance across different autism models are driven by periaqueductal grey hypoexcitability in Setd5 haploinsufficient mice.
Despite the diverse genetic origins of autism spectrum disorders (ASDs), affected individuals share strikingly similar and correlated behavioural traits that include perceptual and sensory processing challenges. Notably, the severity of these sensory symptoms is often predictive of the expression of other autistic traits. However, the origin of these perceptual deficits remains largely elusive. Here, we show a recurrent impairment in visual threat perception that is similarly impaired in 3 independent mouse models of ASD with different molecular aetiologies. Interestingly, this deficit is associated with reduced avoidance of threatening environments-a nonperceptual trait. Focusing on a common cause of ASDs, the Setd5 gene mutation, we define the molecular mechanism. We show that the perceptual impairment is caused by a potassium channel (Kv1)-mediated hypoexcitability in a subcortical node essential for the initiation of escape responses, the dorsal periaqueductal grey (dPAG). Targeted pharmacological Kv1 blockade rescued both perceptual and place avoidance deficits, causally linking seemingly unrelated trait deficits to the dPAG. Furthermore, we show that different molecular mechanisms converge on similar behavioural phenotypes by demonstrating that the autism models Cul3 and Ptchd1, despite having similar behavioural phenotypes, differ in their functional and molecular alteration. Our findings reveal a link between rapid perception controlled by subcortical pathways and appropriate learned interactions with the environment and define a nondevelopmental source of such deficits in ASD.
PubMed: 38857283
DOI: 10.1371/journal.pbio.3002668 -
BioRxiv : the Preprint Server For... May 2024Albinism is an inherited disorder characterized by disrupted melanin production in the eye, and often in the skin and hair. This retinal hypopigmentation is accompanied...
Albinism is an inherited disorder characterized by disrupted melanin production in the eye, and often in the skin and hair. This retinal hypopigmentation is accompanied by pathological decussation of many temporal retinal afferents at the optic chiasm during development, ultimately resulting in partially superimposed representations of opposite visual hemifields in each cortical hemisphere. Within these aberrant regions of hemifield overlap, individual voxels have been shown to have bilateral, dual population receptive fields (pRFs) responding to roughly mirror-image locations across the vertical meridian. Nonetheless, how these two conflicting inputs combine to determine a voxel's response to image contrast is still unknown. To address this, we stimulated the right and left hemifields with separately controlled sinusoidal gratings, each having a variety of contrasts (0, 8, 20, 45, 100%), and extracted voxel-wise BOLD response amplitudes to each contrast combination in visual areas V1-V3. We then compared voxels' responses to each hemifield stimulated individually with conditions when both hemifields were stimulated simultaneously. We hypothesized that simultaneous stimulation of the two pRF components will result in either a suppressive or facilitative interaction. However, we found that BOLD responses to simultaneous stimulation appeared to reflect simple summation of the neural activity from the individual hemifield conditions. This suggests that the superimposed opposite hemifield representations do not interact. Thus, dual pRFs in albinism likely reflect two co-localized, but functionally independent populations of neurons each of which respond to a single hemifield. This finding is commensurate with psychophysical studies which have shown no clear perceptual interaction between opposite visual hemifields in human albinism.
PubMed: 38853944
DOI: 10.1101/2024.05.26.595603