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Nature Communications Nov 2023Introspective agents can recognize the extent to which their internal perceptual experiences deviate from the actual states of the external world. This ability, also...
Introspective agents can recognize the extent to which their internal perceptual experiences deviate from the actual states of the external world. This ability, also known as insight, is critically required for reality testing and is impaired in psychosis, yet little is known about its cognitive underpinnings. We develop a Bayesian modeling framework and a psychophysics paradigm to quantitatively characterize this type of insight while people experience a motion after-effect illusion. People can incorporate knowledge about the illusion into their decisions when judging the actual direction of a motion stimulus, compensating for the illusion (and often overcompensating). Furthermore, confidence, reaction-time, and pupil-dilation data all show signatures consistent with inferential adjustments in the Bayesian insight model. Our results suggest that people can question the veracity of what they see by making insightful inferences that incorporate introspective knowledge about internal distortions.
Topics: Humans; Perceptual Distortion; Illusions; Bayes Theorem; Psychophysics; Psychotic Disorders; Motion Perception
PubMed: 38030601
DOI: 10.1038/s41467-023-42813-2 -
Neuropsychologia Jun 2024Facial identity recognition (FIR) is arguably the ultimate form of recognition for the adult human brain. Even if the term prosopagnosia is reserved for exceptionally... (Review)
Review
Facial identity recognition (FIR) is arguably the ultimate form of recognition for the adult human brain. Even if the term prosopagnosia is reserved for exceptionally rare brain-damaged cases with a category-specific abrupt loss of FIR at adulthood, subjective and objective impairments or difficulties of FIR are common in the neuropsychological population. Here we provide a critical overview of the evaluation of FIR both for clinicians and researchers in neuropsychology. FIR impairments occur following many causes that should be identified objectively by both general and specific, behavioral and neural examinations. We refute the commonly used dissociation between perceptual and memory deficits/tests for FIR, since even a task involving the discrimination of unfamiliar face images presented side-by-side relies on cortical memories of faces in the right-lateralized ventral occipito-temporal cortex. Another frequently encountered confusion is between specific deficits of the FIR function and a more general impairment of semantic memory (of people), the latter being most often encountered following anterior temporal lobe damage. Many computerized tests aimed at evaluating FIR have appeared over the last two decades, as reviewed here. However, despite undeniable strengths, they often suffer from ecological limitations, difficulties of instruction, as well as a lack of consideration for processing speed and qualitative information. Taking into account these issues, a recently developed behavioral test with natural images manipulating face familiarity, stimulus inversion, and correct response times as a key variable appears promising. The measurement of electroencephalographic (EEG) activity in the frequency domain from fast periodic visual stimulation also appears as a particularly promising tool to complete and enhance the neuropsychological assessment of FIR.
Topics: Humans; Facial Recognition; Neuropsychological Tests; Prosopagnosia; Recognition, Psychology; Electroencephalography
PubMed: 38522782
DOI: 10.1016/j.neuropsychologia.2024.108865 -
Cognition May 2024What is the relationship between experiencing individual body parts and the whole body as one's own? We theorised that body part ownership is driven primarily by the...
What is the relationship between experiencing individual body parts and the whole body as one's own? We theorised that body part ownership is driven primarily by the perceptual binding of visual and somatosensory signals from specific body parts, whereas full-body ownership depends on a more global binding process based on multisensory information from several body segments. To examine this hypothesis, we used a bodily illusion and asked participants to rate illusory changes in ownership over five different parts of a mannequin's body and the mannequin as a whole, while we manipulated the synchrony or asynchrony of visual and tactile stimuli delivered to three different body parts. We found that body part ownership was driven primarily by local visuotactile synchrony and could be experienced relatively independently of full-body ownership. Full-body ownership depended on the number of synchronously stimulated parts in a nonlinear manner, with the strongest full-body ownership illusion occurring when all parts received synchronous stimulation. Additionally, full-body ownership influenced body part ownership for nonstimulated body parts, and skin conductance responses provided physiological evidence supporting an interaction between body part and full-body ownership. We conclude that body part and full-body ownership correspond to different processes and propose a hierarchical probabilistic model to explain the relationship between part and whole in the context of multisensory awareness of one's own body.
Topics: Humans; Visual Perception; Body Image; Illusions; Human Body; Ownership; Touch Perception; Hand; Proprioception
PubMed: 38364444
DOI: 10.1016/j.cognition.2023.105697 -
Medicina (Kaunas, Lithuania) Dec 2023: Amblyopia is a neurodevelopmental disorder caused by interocular suppression of visual input, affecting visual acuity, stereopsis, contrast sensitivity, and other... (Review)
Review
: Amblyopia is a neurodevelopmental disorder caused by interocular suppression of visual input, affecting visual acuity, stereopsis, contrast sensitivity, and other visual functions. Conventional treatment comprises occlusion of the sound eye. In recent years, novel therapies that deploy perceptual learning (PL) principles have been introduced. The purpose of this study is to assess the latest scientific data on this topic. : For this purpose, we conducted a literature search for relevant studies published during the previous 4 years (2020-2023). : A plethora of visual perceptual learning protocols have been recently developed. Dichoptic video games, contrast rebalanced movies, and online perceptual training platforms are the main formats. Perceptual learning activates neuroplasticity, overcomes interocular suppression, and improves the visual impairments induced by amblyopia. This novel treatment is effective in both children and adults, as well as in patients non-responding to patching.
Topics: Adult; Child; Humans; Amblyopia; Visual Acuity; Spatial Learning; Neurodevelopmental Disorders; Neuronal Plasticity
PubMed: 38256309
DOI: 10.3390/medicina60010048 -
Philosophical Transactions of the Royal... Sep 2023Almost all decisions in everyday life rely on multiple sensory inputs that can come from common or independent causes. These situations invoke perceptual uncertainty...
Almost all decisions in everyday life rely on multiple sensory inputs that can come from common or independent causes. These situations invoke perceptual uncertainty about environmental properties and the signals' causal structure. Using the audiovisual McGurk illusion, this study investigated how observers formed perceptual and causal confidence judgements in information integration tasks under causal uncertainty. Observers were presented with spoken syllables, their corresponding articulatory lip movements or their congruent and McGurk combinations (e.g. auditory B/P with visual G/K). Observers reported their perceived auditory syllable, the causal structure and confidence for each judgement. Observers were more accurate and confident on congruent than unisensory trials. Their perceptual and causal confidence were tightly related over trials as predicted by the interactive nature of perceptual and causal inference. Further, observers assigned comparable perceptual and causal confidence to veridical 'G/K' percepts on audiovisual congruent trials and their causal and perceptual metamers on McGurk trials (i.e. illusory 'G/K' percepts). Thus, observers metacognitively evaluate the integrated audiovisual percept with limited access to the conflicting unisensory stimulus components on McGurk trials. Collectively, our results suggest that observers form meaningful perceptual and causal confidence judgements about multisensory scenes that are qualitatively consistent with principles of Bayesian causal inference. This article is part of the theme issue 'Decision and control processes in multisensory perception'.
Topics: Humans; Illusions; Auditory Perception; Speech Perception; Visual Perception; Metacognition; Bayes Theorem; Photic Stimulation; Acoustic Stimulation
PubMed: 37545307
DOI: 10.1098/rstb.2022.0348 -
Current Neurology and Neuroscience... Nov 2023To investigate the neurofunctional correlates of pure auditory agnosia and its varieties (global, verbal, and nonverbal), based on 116 anatomoclinical reports published... (Review)
Review
PURPOSE OF REVIEW
To investigate the neurofunctional correlates of pure auditory agnosia and its varieties (global, verbal, and nonverbal), based on 116 anatomoclinical reports published between 1893 and 2022, with emphasis on hemispheric lateralization, intrahemispheric lesion site, underlying cognitive impairments.
RECENT FINDINGS
Pure auditory agnosia is rare, and observations accumulate slowly. Recent patient reports and neuroimaging studies on neurotypical subjects offer insights into the putative mechanisms underlying auditory agnosia, while challenging traditional accounts. Global auditory agnosia frequently results from bilateral temporal damage. Verbal auditory agnosia strictly correlates with language-dominant hemisphere lesions. Damage involves the auditory pathways, but the critical lesion site is unclear. Both the auditory cortex and associative areas are reasonable candidates, but cases resulting from brainstem damage are on record. The hemispheric correlates of nonverbal auditory input disorders are less clear. They correlate with unilateral damage to either hemisphere, but evidence is scarce. Based on published cases, pure auditory agnosias are neurologically and functionally heterogeneous. Phenotypes are influenced by co-occurring cognitive impairments. Future studies should start from these facts and integrate patient data and studies in neurotypical individuals.
Topics: Humans; Agnosia; Auditory Perception
PubMed: 37747655
DOI: 10.1007/s11910-023-01302-1 -
PloS One 2023During the COVID-19 pandemic, personal protective equipment such as facial masks and coverings were mandated all over the globe to protect against the virus. Although...
During the COVID-19 pandemic, personal protective equipment such as facial masks and coverings were mandated all over the globe to protect against the virus. Although the primary aim of wearing face masks is to protect against viral transmission, they pose a potential burden on communication. The purpose of this scoping review was to identify the state of the evidence of the effect of facial coverings on acoustic and perceptual speech outcomes. The scoping review followed the framework created by Arksey & O'Malley (2005) and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews guidelines (PRISMA-ScR; Tricco et al., 2018). The search was completed in May 2021 across the following databases: PubMed, EMBASE, PsycINFO, Web of Science, and Google Scholar. A total of 3,846 records were retrieved from the database search. Following the removal of duplicates, 3,479 remained for the title/abstract screen and 149 were selected for the full-text review. Of these, 52 were included in the final review and relevant data were extracted. The 52 articles included in the final review consisted of; 11 studied perceptual outcomes only, 16 studied acoustic outcomes only, and 14 studied both perceptual and acoustic outcomes. 13 of these investigated acoustic features that could be used for mask classification. Although the findings varied from article to article, many trends stood out. Many articles revealed that face masks act as a low pass filter, dampening sounds at higher frequencies; however, the frequency range and the degree of attenuation varied based on face mask type. All but five articles that reported on perceptual outcomes showed a common trend that wearing a face mask was associated with poorer speech intelligibility. The findings of the scoping review provided evidence that facial coverings negatively impacted speech intelligibility, which is likely due to a combination of auditory and visual cue degradation. Due to the continued prevalence of mask use, how facial coverings affect a wider variety of speaker populations, such as those with communication impairments, and strategies for overcoming communication challenges should be explored.
Topics: Humans; Acoustics; COVID-19; Masks; Pandemics; Speech Intelligibility
PubMed: 37624795
DOI: 10.1371/journal.pone.0285009 -
CoDAS 2023To analyze the effect of auditory-perceptual training by inexperienced speech-language pathologists in the classification of hypernasality in individuals with cleft lip...
PURPOSE
To analyze the effect of auditory-perceptual training by inexperienced speech-language pathologists in the classification of hypernasality in individuals with cleft lip and palate and compare their classification of hypernasality individually, with the gold standard evaluation, before and after this training.
METHODS
Three inexperienced speech-language pathologists used a four-point scale to assess 24 high-pressure speech samples from individuals with cleft lip and palate, before and after auditory-perceptual training. The speech samples corresponded to six samples of each degree of hypernasality. The speech-language pathologists received auditory-perceptual training during the assessments. They had access to anchor samples and immediate feedback of correct answers regarding the degree of hypernasality in training.
RESULTS
There was no significant difference in the overall percentage of correct answers when comparing before and after the auditory-perceptual training. There was a significant association and agreement of the three evaluators with a gold standard evaluation after training, with an increase in agreement for a single evaluator for absent and mild degrees of hypernasality. The dichotomous analysis of the data showed an increase in the Kappa Index of Agreement of this evaluator. Although there was an increase in the Index of Agreement between evaluators for absent, mild, and severe hypernasality, this increase did not reach statistical significance.
CONCLUSION
The auditory-perceptual training provided did not result in a significant improvement in the hypernasality classification for the inexperienced speech-language pathologists, even though the individual data analysis showed that the training favored one of the evaluators. Further studies involving gradual and more extensive auditory-perceptual training may favor the classification of hypernasality by inexperienced SLPs.
Topics: Humans; Cleft Lip; Cleft Palate; Speech; Voice Disorders
PubMed: 37729318
DOI: 10.1590/2317-1782/20232022069pt -
Scientific Reports Apr 2024Hallucinations and delusions can be symptoms of psychiatric illness, but more often—though less commonly known—are actually part of a healthy range of experiences...
Hallucinations and delusions can be symptoms of psychiatric illness, but more often—though less commonly known—are actually part of a healthy range of experiences found throughout the general population. The studies in this Special Collection paint a picture of the wide range of hallucinatory and delusional experiences across diverse populations, as well as comparative perspectives between clinical and non-clinical samples. In this editorial, I make three related points that are exemplified in the articles published here. First, that hallucinations and delusions are part of a normal distribution of human diversity; their mere presence does not indicate psychosis or psychiatric illness. Second, that the ubiquity of hallucinatory and delusional experiences across clinical and non-clinical populations suggests common cognitive and neural mechanisms. Finally, despite these commonalities, it is important to understand the difference between psychiatric symptoms and healthy experience. In summary, I conclude that it is important to investigate both common mechanisms and distinguishing factors to comprehensively elucidate these oft-misunderstood experiences. This Special Collection provides a showcase of the cutting-edge research that encompasses these objectives.
Topics: Humans; Delusions; Hallucinations; Psychotic Disorders; Forecasting
PubMed: 38600126
DOI: 10.1038/s41598-024-57472-6 -
Journal of Clinical Medicine Jul 2023The assessment of voice quality can be evaluated perceptually with standard clinical practice, also including acoustic evaluation of digital voice recordings to validate...
BACKGROUND
The assessment of voice quality can be evaluated perceptually with standard clinical practice, also including acoustic evaluation of digital voice recordings to validate and further interpret perceptual judgments. The goal of the present study was to determine the strongest acoustic voice quality parameters for perceived hoarseness and breathiness when analyzing the sustained vowel [a:] using a new clinical acoustic tool, the VOXplot software.
METHODS
A total of 218 voice samples of individuals with and without voice disorders were applied to perceptual and acoustic analyses. Overall, 13 single acoustic parameters were included to determine validity aspects in relation to perceptions of hoarseness and breathiness.
RESULTS
Four single acoustic measures could be clearly associated with perceptions of hoarseness or breathiness. For hoarseness, the harmonics-to-noise ratio (HNR) and pitch perturbation quotient with a smoothing factor of five periods (PPQ5), and, for breathiness, the smoothed cepstral peak prominence (CPPS) and the glottal-to-noise excitation ratio (GNE) were shown to be highly valid, with a significant difference being demonstrated for each of the other perceptual voice quality aspects.
CONCLUSIONS
Two acoustic measures, the HNR and the PPQ5, were both strongly associated with perceptions of hoarseness and were able to discriminate hoarseness from breathiness with good confidence. Two other acoustic measures, the CPPS and the GNE, were both strongly associated with perceptions of breathiness and were able to discriminate breathiness from hoarseness with good confidence.
PubMed: 37510759
DOI: 10.3390/jcm12144644