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Molecular Autism Jun 2024Categorization and its influence on perceptual discrimination are essential processes to organize information efficiently. Individuals with Autism Spectrum Condition...
BACKGROUND
Categorization and its influence on perceptual discrimination are essential processes to organize information efficiently. Individuals with Autism Spectrum Condition (ASC) are suggested to display enhanced discrimination on the one hand, but also to experience difficulties with generalization and ignoring irrelevant differences on the other, which underlie categorization. Studies on categorization and discrimination in ASC have mainly focused on one process at a time, however, and typically only used either behavioral or neural measures in isolation. Here, we aim to investigate the interrelationships between these perceptual processes using novel stimuli sampled from a well-controlled artificial stimulus space. In addition, we complement standard behavioral psychophysical tasks with frequency-tagging EEG (FT-EEG) to obtain a direct, non-task related neural index of discrimination and categorization.
METHODS
The study was completed by 38 adults with ASC and 38 matched neurotypical (NT) individuals. First, we assessed baseline discrimination sensitivity by administering FT-EEG measures and a complementary behavioral task. Second, participants were trained to categorize the stimuli into two groups. Finally, participants again completed the neural and behavioral discrimination sensitivity measures.
RESULTS
Before training, NT participants immediately revealed a categorical tuning of discrimination, unlike ASC participants who showed largely similar discrimination sensitivity across the stimuli. During training, both autistic and non-autistic participants were able to categorize the stimuli into two groups. However, in the initial training phase, ASC participants were less accurate and showed more variability, as compared to their non-autistic peers. After training, ASC participants showed significantly enhanced neural and behavioral discrimination sensitivity across the category boundary. Behavioral indices of a reduced categorical processing and perception were related to the presence of more severe autistic traits. Bayesian analyses confirmed overall results.
LIMITATIONS
Data-collection occurred during the COVID-19 pandemic.
CONCLUSIONS
Our behavioral and neural findings indicate that adults with and without ASC are able to categorize highly similar stimuli. However, while categorical tuning of discrimination sensitivity was spontaneously present in the NT group, it only emerged in the autistic group after explicit categorization training. Additionally, during training, adults with autism were slower at category learning. Finally, this multi-level approach sheds light on the mechanisms underlying sensory and information processing issues in ASC.
Topics: Humans; Male; Adult; Female; Electroencephalography; Young Adult; Autistic Disorder; Discrimination, Psychological; Learning; Photic Stimulation; Visual Perception; Autism Spectrum Disorder
PubMed: 38831439
DOI: 10.1186/s13229-024-00604-6 -
ELife Jun 2024
PubMed: 38829696
DOI: 10.7554/eLife.100253 -
Frontiers in Human Neuroscience 2024Our brain constantly integrates afferent information, such as visual and tactile information, to perceive the world around us. According to the maximum-likelihood...
Our brain constantly integrates afferent information, such as visual and tactile information, to perceive the world around us. According to the maximum-likelihood estimation (MLE) model, imprecise information will be weighted less than precise, making the multisensory percept as precise as possible. Individuals with fibromyalgia (FM), a chronic pain syndrome, show alterations in the integration of tactile information. This could lead to a decrease in their weight in a multisensory percept or a general disruption of multisensory integration, making it less beneficial. To assess multisensory integration, 15 participants with FM and 18 pain-free controls performed a temporal-order judgment task in which they received pairs of sequential visual, tactile (unisensory conditions), or visuotactile (multisensory condition) stimulations on the index and the thumb of the non-dominant hand and had to determine which finger was stimulated first. The task enabled us to measure the precision and accuracy of the percept in each condition. Results indicate an increase in precision in the visuotactile condition compared to the unimodal conditions in controls only, although we found no intergroup differences. The observed visuotactile precision was correlated to the precision predicted by the MLE model in both groups, suggesting an optimal integration. Finally, the weights of the sensory information were not different between the groups; however, in the group with FM, higher pain intensity was associated with smaller tactile weight. This study shows no alterations of the visuotactile integration in individuals with FM, though pain may influence tactile weight in these participants.
PubMed: 38826615
DOI: 10.3389/fnhum.2024.1390609 -
PloS One 2024Saccadic eye movements enable us to search for the target of interest in a crowded scene or, in the case of goal-directed saccades, to simply bring the image of the...
Saccadic eye movements enable us to search for the target of interest in a crowded scene or, in the case of goal-directed saccades, to simply bring the image of the peripheral target to the very centre of the fovea. This mechanism extends the use of the superior image processing performance of the fovea over a large visual field. We know that visual information is processed quickly at the end of each saccade but estimates of the times involved remain controversial. This study aims to investigate the processing of visual information during post fixation oscillations of the eyeball. A new psychophysical test measures the combined eye movement response latencies, including fixation duration and visual processing times. When the test is used in conjunction with an eye tracker, each component that makes up the 'integrated saccade latency' time, from the onset of the peripheral stimulus to the correct interpretation of the information carried by the stimulus, can be measured and the discrete components delineated. The results show that the time required to process and encode the stimulus attribute of interest at the end of a saccade is longer than the time needed to carry out the same task in the absence of an eye movement. We propose two principal hypotheses, each of which can account for this finding. 1. The known inhibition of afferent retinal signals during fast eye movements extends beyond the end point of the saccade. 2. The extended visual processing times measured when saccades are involved are caused by the transient loss of spatial resolution due to eyeball instability during post-saccadic oscillations. The latter can best be described as retinal image smear with greater loss of spatial resolution expected for stimuli of low luminance contrast.
Topics: Humans; Saccades; Adult; Male; Female; Reaction Time; Visual Perception; Fixation, Ocular; Young Adult; Photic Stimulation; Visual Fields; Time Factors
PubMed: 38809939
DOI: 10.1371/journal.pone.0302459 -
Proceedings. Biological Sciences May 2024The ambient daylight variation is coded by melanopsin photoreceptors and their luxotonic activity increases towards midday when colour temperatures are cooler, and...
The ambient daylight variation is coded by melanopsin photoreceptors and their luxotonic activity increases towards midday when colour temperatures are cooler, and irradiances are higher. Although melanopsin and cone photoresponses can be mediated via separate pathways, the connectivity of melanopsin cells across all levels of the retina enables them to modify cone signals. The downstream effects of melanopsin-cone interactions on human vision are however, incompletely understood. Here, we determined how the change in daytime melanopsin activation affects the human cone pathway signals in the visual cortex. A 5-primary silent-substitution method was developed to evaluate the dependence of cone-mediated signals on melanopsin activation by spectrally tuning the lights and stabilizing the rhodopsin activation under a constant cone photometric luminance. The retinal (white noise electroretinogram) and cortical responses (visual evoked potential) were simultaneously recorded with the photoreceptor-directed lights in 10 observers. By increasing the melanopsin activation, a reverse response pattern was observed with cone signals being supressed in the retina by 27% ( = 0.03) and subsequently amplified by 16% ( = 0.01) as they reach the cortex. We infer that melanopsin activity can amplify cone signals at sites distal to retinal bipolar cells to cause a decrease in the psychophysical Weber fraction for cone vision.
Topics: Humans; Rod Opsins; Retinal Cone Photoreceptor Cells; Visual Cortex; Adult; Electroretinography; Evoked Potentials, Visual; Female; Male; Young Adult; Photic Stimulation
PubMed: 38808443
DOI: 10.1098/rspb.2023.2708 -
Proceedings of the National Academy of... Jun 2024Neural oscillations reflect fluctuations in excitability, which biases the percept of ambiguous sensory input. Why this bias occurs is still not fully understood. We...
Neural oscillations reflect fluctuations in excitability, which biases the percept of ambiguous sensory input. Why this bias occurs is still not fully understood. We hypothesized that neural populations representing likely events are more sensitive, and thereby become active on earlier oscillatory phases, when the ensemble itself is less excitable. Perception of ambiguous input presented during less-excitable phases should therefore be biased toward frequent or predictable stimuli that have lower activation thresholds. Here, we show such a frequency bias in spoken word recognition using psychophysics, magnetoencephalography (MEG), and computational modelling. With MEG, we found a double dissociation, where the phase of oscillations in the superior temporal gyrus and medial temporal gyrus biased word-identification behavior based on phoneme and lexical frequencies, respectively. This finding was reproduced in a computational model. These results demonstrate that oscillations provide a temporal ordering of neural activity based on the sensitivity of separable neural populations.
Topics: Humans; Magnetoencephalography; Language; Speech Perception; Male; Female; Adult; Temporal Lobe; Young Adult; Models, Neurological
PubMed: 38805278
DOI: 10.1073/pnas.2320489121 -
Medical Sciences (Basel, Switzerland) May 2024In clinical practice, the implementation of tailored treatment is crucial for assessing the patient's emotional processing profile. Here, we investigate all three levels... (Observational Study)
Observational Study
BACKGROUND
In clinical practice, the implementation of tailored treatment is crucial for assessing the patient's emotional processing profile. Here, we investigate all three levels of analysis characterizing emotion processing, i.e., recognition, representation, and regulation, in patients with peripheral neuropathic pain (PNP).
METHODS
Sixty-two patients and forty-eight healthy controls underwent quantitative sensory testing, i.e., psychophysical tests to assess somatosensory functions such as perception of cold (CDT), heat-induced pain (HPT), and vibration (VDT), as well as three standardized tasks to assess emotional processing: (1) the Ekman 60-Faces Test (EK-60F) to assess recognition of basic facial emotions, (2) the Reading the Mind in the Eyes Test (RME) to assess the ability to represent the feelings of another person by observing their eyes, and (3) the 20-item Toronto Alexithymia Scale (TAS-20) to assess emotional dysregulation, i.e., alexithymia.
RESULTS
General Linear Model analysis revealed a significant relationship between left index finger VDT z-scores in PNP patients with alexithymia. The RME correlated with VDT z-scores of the left little finger and overall score for the EK-60F.
CONCLUSIONS
In patients with PNP, emotion processing is impaired, which emphasizes the importance of assessing these abilities appropriately in these patients. In this way, clinicians can tailor treatment to the needs of individual patients.
Topics: Humans; Male; Female; Middle Aged; Neuralgia; Emotions; Aged; Adult; Affective Symptoms; Case-Control Studies
PubMed: 38804383
DOI: 10.3390/medsci12020027 -
European Journal of Investigation in... May 2024This study aims to validate the Spanish version of the Measure of Happiness (MH), a questionnaire that identifies the specific areas of an individual's life that are...
This study aims to validate the Spanish version of the Measure of Happiness (MH), a questionnaire that identifies the specific areas of an individual's life that are related to experienced happiness. The sample consisted of 458 Spanish native speakers (65.7% women, 34.3% men; mean age = 24.14, = 8.45) and was divided into two groups: Sample 1 (N = 226) underwent Exploratory Factor Analysis (EFA), and Sample 2 (N = 232) underwent Confirmatory Factor Analysis (CFA). The convergent and discriminant validity of the Spanish version of the MH and its subscales was assessed by calculating Pearson correlations between the MH factors and the Subjective Happiness Scale, the State-Trait Anxiety Inventory, the Beck Depression Inventory, and the WHOQOL-BREF. The EFA and CFA confirmed the original five-factor structure of the MH questionnaire. The only difference in the Spanish version of the MH is that Item 4, which was originally assigned to Factor 2 "Financial Status", was reallocated to Factor 1 "Psychophysical Status". The reliability of the Spanish version of the MH questionnaire was also confirmed, and the factors correlated in the expected direction with the constructs of quality of life, happiness, anxiety, and depression. The MH questionnaire demonstrated excellent psychometric properties among Spanish respondents.
PubMed: 38785588
DOI: 10.3390/ejihpe14050090 -
European Journal of Investigation in... May 2024Breast cancer (BC)-related sequelae drastically impact the psychophysical functioning and quality of life of affected women. Adapted physical activity (APA) has proved...
Breast cancer (BC)-related sequelae drastically impact the psychophysical functioning and quality of life of affected women. Adapted physical activity (APA) has proved to effectively counteract these impairments in a non-medicalized framework. In particular, dragon boats are able to promote body functionality, social interaction, and quality of life in BC survivors, but the literature on specific motor gestures is scarce and practice is still based more on a re-educative perspective than a performative one. In this context, the present longitudinal study investigated the benefits of an adapted biofeedback-based sensorimotor training intervention on upper body functionality in a team of dragon ladies. The 8-week intervention was conceived as integrated dry workout sessions led by an APA kinesiologist and applied a novel sensorized proprioceptive device, such as a Libra board. Post-protocol evaluation revealed a significant improvement in bilateral upper limb mobility, core endurance, and trunk stability along with a distress decrease and quality of life enhancement through validated assessment tools. Our findings suggest that integrating biofeedback-based workout sessions can effectively promote upper body functionality in BC survivors practicing dragon boating. Furthermore, our innovative approach could help spread methodological hints able to boost exercise adherence in this target population, thus counteracting cancer recurrence while promoting overall well-being.
PubMed: 38785587
DOI: 10.3390/ejihpe14050089 -
European Journal of Investigation in... Apr 2024Long COVID refers to the persistence or development of signs and symptoms well after the acute phase of COVID-19.
BACKGROUND
Long COVID refers to the persistence or development of signs and symptoms well after the acute phase of COVID-19.
OBJECTIVE OF THE STUDY
To investigate the long-term outcomes of the SARS-CoV-2 infection in terms of psychological, social, and relational consequences within the Italian population.
MATERIALS AND METHODS
We conducted an observational, cross-sectional, and multicenter study using an online questionnaire distributed to a sample of the Italian population. By utilizing the Short Form 12 Health Survey (SF-12) and the Hikikomori scale, we assessed perceived quality of life and social isolation, respectively. The questionnaire also included an open-answer question: "What will you remember about the pandemic period?". We used generative artificial intelligence to analyze and summarize the corresponding answers.
RESULTS
A total of 1097 people participated in this study. A total of 79.3% (n = 870) of participants declared that they had been hospitalized and 62.8% (n = 689) received home care. Physical symptoms included headaches (43%, n = 472) and asthma (30.4%, n = 334). Additionally, 29.2% (n = 320) developed an addiction during the pandemic and, among these, 224 claimed internet addiction while 73 declared an emotional addiction. Furthermore, 51.8% (n = 568) experienced limitations in carrying out daily life activities. According to the Hikikomori scale, participants with positive SARS-CoV-2 infection exhibited higher levels of isolation compared to the others ( < 0.001). Participants without COVID-19 showed higher levels of emotional support ( < 0.001). Our semiautomatic analysis of the open-ended responses, obtained by a procedure based on a free large language model, allowed us to deduce and summarize the main feelings expressed by the interviewees regarding the pandemic.
CONCLUSIONS
The data collected emphasize the urgent need to investigate the consequences of long COVID in order to implement interventions to support psychological well-being.
PubMed: 38785574
DOI: 10.3390/ejihpe14050076