Brain Responses Research Articles

Brain-Inspired Image Perceptual Quality Assessment Based on EEG: A QoE Perspective.

Human-oriented image communication should take the quality of experience (QoE) as an optimization goal, which requires effective image perceptual quality metrics. However, traditional user-based assessment metrics are limited by the deviation caused by human high-level cognitive activities. To tackle this issue, in this paper, we construct a brain response-based image perceptual quality metric and develop a brain-inspired network to assess the image perceptual quality based on it. Our method aims to establish the relationship between image quality changes and underlying brain responses in image compression scenarios using the electroencephalography (EEG) approach. We first establish EEG datasets by collecting the corresponding EEG signals when subjects watch distorted images. Then, we design a measurement model to extract EEG features that reflect human perception to establish a new image perceptual quality metric: EEG perceptual score (EPS). To use this metric in practical scenarios, we embed the brain perception process into a prediction model to generate the EPS directly from the input images. Experimental results show that our proposed measurement model and prediction model can achieve better performance. The proposed brain response-based image perceptual quality metric can measure the human brain's perceptual state more accurately, thus performing a better assessment of image perceptual quality.

Functional connectivity of stimulus-evoked brain responses to natural speech in post-stroke aphasia

Objective. One out of three stroke-patients develop language processing impairment known as aphasia. The need for ecological validity of the existing diagnostic tools motivates research on biomarkers, such as stimulus-evoked brain responses. With the aim of enhancing the physiological interpretation of the latter, we used EEG to investigate how functional brain network patterns associated with the neural response to natural speech are affected in persons with post-stroke chronic aphasia.Approach. EEG was recorded from 24 healthy controls and 40 persons with aphasia while they listened to a story. Stimulus-evoked brain responses at all scalp regions were measured as neural envelope tracking in the delta (0.5-4 Hz), theta (4-8 Hz) and low-gamma bands (30-49 Hz) using mutual information. Functional connectivity between neural-tracking signals was measured, and the Network-Based Statistics toolbox was used to: (1) assess the added value of the neural tracking vs EEG time series, (2) test between-group differences and (3) investigate any association with language performance in aphasia. Graph theory was also used to investigate topological alterations in aphasia.Main results. Functional connectivity was higher when assessed from neural tracking compared to EEG time series. Persons with aphasia showed weaker low-gamma-band left-hemispheric connectivity, and graph theory-based results showed a greater network segregation and higher region-specific node strength. Aphasia also exhibited a correlation between delta-band connectivity within the left pre-frontal region and language performance.Significance.We demonstrated the added value of combining brain connectomics with neural-tracking measurement when investigating natural speech processing in post-stroke aphasia. The higher sensitivity to language-related brain circuits of this approach favors its use as informative biomarker for the assessment of aphasia.

A distributed brain response predicting the facial expression of acute nociceptive pain.

Pain is a private experience observable through various verbal and non-verbal behavioural manifestations, each of which may relate to different pain-related functions. Despite the importance of understanding the cerebral mechanisms underlying those manifestations, there is currently limited knowledge of the neural correlates of the facial expression of pain. In this functional magnetic resonance imaging (fMRI) study, noxious heat stimulation was applied in healthy volunteers and we tested if previously published brain signatures of pain were sensitive to pain expression. We then applied a multivariate pattern analysis to the fMRI data to predict the facial expression of pain. Results revealed the inability of previously developed pain neurosignatures to predict the facial expression of pain. We thus propose a facial expression of pain signature (FEPS) conveying distinctive information about the brain response to nociceptive stimulations with minimal or no overlap with other pain-relevant brain signatures associated with nociception, pain ratings, thermal pain aversiveness, or pain valuation. The FEPS may provide a distinctive functional characterization of the distributed cerebral response to nociceptive pain associated with the socio-communicative role of non-verbal pain expression. This underscores the complexity of pain phenomenology by reinforcing the view that neurosignatures conceived as biomarkers must be interpreted in relation to the specific pain manifestation(s) predicted and their underlying function(s). Future studies should explore other pain-relevant manifestations and assess the specificity of the FEPS against simulated pain expressions and other types of aversive or emotional states.

A distributed brain response predicting the facial expression of acute nociceptive pain

Pain is a private experience observable through various verbal and non-verbal behavioural manifestations, each of which may relate to different pain-related functions. Despite the importance of understanding the cerebral mechanisms underlying those manifestations, there is currently limited knowledge of the neural correlates of the facial expression of pain. In this functional magnetic resonance imaging (fMRI) study, noxious heat stimulation was applied in healthy volunteers and we tested if previously published brain signatures of pain were sensitive to pain expression. We then applied a multivariate pattern analysis to the fMRI data to predict the facial expression of pain. Results revealed the inability of previously developed pain neurosignatures to predict the facial expression of pain. We thus propose a facial expression of pain signature (FEPS) conveying distinctive information about the brain response to nociceptive stimulations with minimal or no overlap with other pain-relevant brain signatures associated with nociception, pain ratings, thermal pain aversiveness, or pain valuation. The FEPS may provide a distinctive functional characterization of the distributed cerebral response to nociceptive pain associated with the socio-communicative role of non-verbal pain expression. This underscores the complexity of pain phenomenology by reinforcing the view that neurosignatures conceived as biomarkers must be interpreted in relation to the specific pain manifestation(s) predicted and their underlying function(s). Future studies should explore other pain-relevant manifestations and assess the specificity of the FEPS against simulated pain expressions and other types of aversive or emotional states.

Deep-learning models reveal how context and listener attention shape electrophysiological correlates of speech-to-language transformation.

To transform continuous speech into words, the human brain must resolve variability across utterances in intonation, speech rate, volume, accents and so on. A promising approach to explaining this process has been to model electroencephalogram (EEG) recordings of brain responses to speech. Contemporary models typically invoke context invariant speech categories (e.g. phonemes) as an intermediary representational stage between sounds and words. However, such models may not capture the complete picture because they do not model the brain mechanism that categorizes sounds and consequently may overlook associated neural representations. By providing end-to-end accounts of speech-to-text transformation, new deep-learning systems could enable more complete brain models. We model EEG recordings of audiobook comprehension with the deep-learning speech recognition system Whisper. We find that (1) Whisper provides a self-contained EEG model of an intermediary representational stage that reflects elements of prelexical and lexical representation and prediction; (2) EEG modeling is more accurate when informed by 5-10s of speech context, which traditional context invariant categorical models do not encode; (3) Deep Whisper layers encoding linguistic structure were more accurate EEG models of selectively attended speech in two-speaker "cocktail party" listening conditions than early layers encoding acoustics. No such layer depth advantage was observed for unattended speech, consistent with a more superficial level of linguistic processing in the brain.

Unique cortical and subcortical activation patterns for different conspecific calls in marmosets.

The common marmoset (Callithrix jacchus) is known for its highly vocal nature, displaying a diverse range of calls. Functional imaging in marmosets has shown that the processing of conspecific calls activates a brain network that includes fronto-temporal areas. It is currently unknown whether different call types activate the same or different networks. In this study, nine adult marmosets (four females) were exposed to four common vocalizations (phee, chatter, trill, and twitter), and their brain responses were recorded using event-related fMRI at 9.4T. We found robust activations in the auditory cortices, encompassing core, belt, and parabelt regions, and in subcortical areas like the inferior colliculus, medial geniculate nucleus, and amygdala in response to these calls. Although a common network was engaged, distinct activity patterns were evident for different vocalizations that could be distinguished by a 3D convolution neural network, indicating unique neural processing for each vocalization. Our findings also indicate the involvement of the cerebellum and medial prefrontal cortex (mPFC) in distinguishing particular vocalizations from others.Significance Statement This study investigates the neural processing of vocal communications in the common marmoset (Callithrix jacchus). Utilizing event-related fMRI at 9.4T, we demonstrate that different calls (phee, chatter, trill, and twitter) elicit distinct brain activation patterns, challenging the notion of a uniform neural network for all vocalizations. Each call type distinctly engages various regions within the auditory cortices and subcortical areas. These findings offer insights into the evolutionary mechanisms of primate vocal perception and provide a foundation for understanding the origins of human speech and language processing.

Empathy enhances decoding accuracy of human neurophysiological responses to emotional facial expressions of humans and dogs.

Despite the growing interest in the non-human animal emotionality, we currently know little about the human brain processing of non-conspecific emotional expressions. Here, we characterized the millisecond-scale temporal dynamics of human brain responses to conspecific human and non-conspecific canine emotional facial expressions. Our results revealed generally similar cortical responses to human and dog facial expressions in the occipital cortex during the first 500 ms, temporal cortex at 100-500 ms and parietal cortex at 150-350 ms from the stimulus onset. Responses to dog faces were pronounced at the latencies in temporal cortices corresponding to the time windows of early posterior negativity (EPN) and late posterior positivity (LPP), suggesting attentional engagement to emotionally salient stimuli. We also utilized support vector machine -based classifiers to discriminate between the brain responses to different images. The subject trait-level empathy correlated with the accuracy of classifying the brain responses of aggressive from happy dog faces, and happy from neutral human faces. This result likely reflects the attentional enhancement provoked by the subjective ecological salience of the stimuli.

Synchronization-based fusion of EEG and eye blink signals for enhanced decoding accuracy

Decoding locomotor tasks is crucial in cognitive neuroscience for understanding brain responses to physical tasks. Traditional methods like EEG offer brain activity insights but may require additional modalities for enhanced interpretative precision and depth. The integration of EEG with ocular metrics, particularly eye blinks, presents a promising avenue for understanding cognitive processes by combining neural and ocular behaviors. However, synchronizing EEG and eye blink activities poses a significant challenge due to their frequently inconsistent alignment. Our study with 35 participants performing various locomotor tasks such as standing, walking, and transversing obstacles introduced a novel methodology, pcEEG+, which fuses EEG principal components (pcEEG) with aligned eye blink data (syncBlink). The results demonstrated that pcEEG+ significantly improved decoding accuracy in locomotor tasks, reaching 78% in some conditions, and surpassed standalone pcEEG and syncBlink methods by 7.6% and 22.7%, respectively. The temporal generalization matrix confirmed the consistency of pcEEG+ across tasks and times. The results were replicated using two driving simulator datasets, thereby confirming the validity of our method. This study demonstrates the efficacy of the pcEEG+ method in decoding locomotor tasks, underscoring the importance of temporal synchronization for accuracy and offering a deeper insight into brain activity during complex movements.

Brain response to sound motion-onset in human

This review comprehensively examines the features of the motion-specific brain response produced by human hearing system, the so-called motion-onset response (MOR). We discuss the interpretations of this component of auditory evoked potentials, its dependence on velocity and direction of sound motion and on various spatial characteristics of sound stimuli. We review the studies of event-related oscillations underlying the MOR which have shown that gradual sound motion causes the phase alignment of the delta-alpha range to the motion onset. We also consider the influence of audio-visual integration on motion processing. The MOR component as a correlate of the processes of spatial integration can provide new information about an early pre-conscious activation of brain structures that facilitates orientation and adaptation of a person to a changing acoustic environment.

Olfactory Development and Dysfunction - Involvement of Microglia.

Olfactory deficits are increasingly recognized in a variety of neurological, neurodevelopmental, psychiatric and viral diseases. While the pathology underlying olfactory loss is likely to differ across diseases, one shared feature may be an immune response mediated by microglia. Microglia orchestrate the brain's response to environmental insults and maintain neurodevelopmental homeostasis. Here, we explore the potential involvement of microglia in olfactory development and loss in disease. The effects of microglia-mediated immune response during development may be of special relevance to the olfactory system, which is unique in both its vulnerability to environmental insults as well as its extended period of neurogenesis and neuronal migration.

Memantine treatment in sickle cell disease: A 1-year study of its effects on cognitive functions and neural processing.

This study evaluates the neurocognitive and electrophysiological effects of 1-year memantine treatment in 14 adolescents and young adults (mean age 24 years) with sickle cell disease (SCD, incluing sickle cell anaemia and sickle cell β-thalassemia), hypothesizing improvements in cognitive functions and neural processing. Participants underwent assessments using subtests from the Wechsler Intelligence Scale and a computerized task-switching paradigm with concurrent event-related potential (ERP) recordings, both before and after the treatment period. Assessments focused on processing speed, working memory, attention and executive function. ERP measurements targeted brain response changes during task switching. Memantine treatment enhanced cognitive test performance, especially in processing speed as shown by the Digit-Symbol Coding and Symbol-Search tests. Results indicated improved visuospatial and graphomotor speed, working memory and attention. The task-switching test revealed reduced error rates, suggesting decreased cognitive load and enhanced executive control. Electrophysiological changes in P1 and P3 amplitudes at frontal and parietal locations post-treatment pointed to more efficient neural processing in tasks requiring cognitive flexibility. These preliminary findings from a Phase II clinical study serve as a 'proof of concept', exploring the feasibility and potential effectiveness of memantine treatment in SCD-a previously uninvestigated context. They support the rationale for more extensive investigations to confirm these results and assess memantine's broader effectiveness.

The Power of Neuromarketing as a Fuel to Drive Purchases in Local Retail (Piura 2024")

Neuromarketing studies the neurological brain responses to various marketing stimuli, such as visual, sound, colour and emotional elements, in order to understand in depth the cognitive and affective processes associated with consumer decision-making. Given its relevance, the objective is to determine how the power of neuromarketing acts as a fuel to drive purchase in a local retail store - Piura 2024. Methodologically, a quantitative approach was used with a non-experimental, descriptive-correlational and transversal design. A total of 384 frequent customers, of legal age and with purchasing power, participated. The findings of this study are an irrefutable testimony to the transformative power of neuromarketing in this local setting (Piura). With a Spearman correlation coefficient of 0.823 (p < 0.01), a strong and statistically significant positive correlation between neuromarketing and purchase decision is revealed, demonstrating that this innovative discipline has the ability to profoundly influence consumer behaviour. These results are a call to action for companies in the sector to adopt neuromarketing strategies that allow them to connect with their customers in a more effective and emotional way, thus unleashing an unprecedented impact on their commercial success. Received: 4 August 2024 / Accepted: 29 October 2024 / Published: 05 November 2024

Neural empathy mechanisms are shared for physical and social pain, and increase from adolescence to older adulthood.

Empathy is a critical component of social interaction that enables individuals to understand and share the emotions of others. We report a pre-registered experiment in which 240 participants, including adolescents, young adults and older adults, viewed images depicting hands and feet in physically or socially painful situations (vs. non-painful). Empathy was measured using imagined pain ratings and EEG mu suppression. Imagined pain was greater for physical vs. social pain, with young adults showing particular sensitivity to social pain events compared to adolescents and older adults. Mu desynchronisation was greater to pain vs. no-pain situations, but the physical/social context did not modulate pain responses. Brain responses to painful situations increased linearly from adolescence to young and older adulthood. These findings highlight shared activity across the core empathy network for both physical and social pain contexts, and an empathic response that develops over the lifespan with accumulating social experience.

Tactile perception of rough surface based on skin friction and brain response

Tactile perception of rough surface based on skin friction and brain response

Border-Associated Macrophages: From Embryogenesis to Immune Regulation.

Border-associated macrophages (BAMs) play a pivotal role in maintaining brain homeostasis and responding to pathological conditions. Understanding their origins, characteristics, and roles in both healthy and diseased brains is crucial for advancing our knowledge of neuroinflammatory and neurodegenerative diseases. This review addresses the ontogeny, replenishment, microenvironmental regulation, and transcriptomic heterogeneity of BAMs, highlighting recent advancements in lineage tracing and fate-mapping studies. Furthermore, we examine the roles of BAMs in maintaining brain homeostasis, immune surveillance, and responses to injury and neurodegenerative diseases. Further research is crucial to clarify the dynamic interplay between BAMs and the brain's microenvironment in health and disease. This effort will not only resolve existing controversies but also reveal new therapeutic targets for neuroinflammatory and neurodegenerative disorders, pushing the boundaries of neuroscience.

A Functional Magnetic Resonance Imaging Study of Phrase Structure and Subject Island Violations.

In principle, functional neuroimaging provides uniquely informative data in addressing linguistic questions, because it can indicate distinct processes that are not apparent from behavioral data alone. This could involve adjudicating the source of unacceptability via the different patterns of elicited brain responses to different ungrammatical sentence types. However, it is difficult to interpret brain activations to syntactic violations. Such responses could reflect processes that have nothing intrinsically related to linguistic representations, such as domain-general executive function abilities. To facilitate the potential use of functional neuroimaging methods to identify the source of different syntactic violations, we conducted a functional magnetic resonance imaging experiment to identify the brain activation maps associated with two distinct syntactic violation types: phrase structure (created by inverting the order of two adjacent words within a sentence) and subject islands (created by extracting a wh-phrase out of an embedded subject). The comparison of these violations to control sentences surprisingly showed no indication of a generalized violation response, with almost completely divergent activation patterns. Phrase structure violations seemingly activated regions previously implicated in verbal working memory and structural complexity in sentence processing, whereas the subject islands appeared to activate regions previously implicated in conceptual-semantic processing, broadly defined. We review our findings in the context of previous research on syntactic and semantic violations using ERPs. Although our results suggest potentially distinct underlying mechanisms underlying phrase structure and subject island violations, our results are tentative and suggest important methodological considerations for future research in this area.

Pain-Discriminating Information Decoded From Spatiotemporal Patterns of Hemodynamic Responses Measured by fMRI in the Human Brain.

Functional magnetic resonance imaging (fMRI) has been widely used in studying the neural mechanisms of pain in the human brain, primarily focusing on where in the brain pain-elicited neural activities occur (i.e., the spatial distribution of pain-related brain activities). However, the temporal dynamics of pain-elicited hemodynamic responses (HDRs) measured by fMRI may also contain information specific to pain processing but have been largely neglected. Using high temporal resolution fMRI (TR = 0.8 s) data acquired from 62 healthy participants, in the present study we aimed to test whether pain-distinguishing information could be decoded from the spatial pattern of the temporal dynamics (i.e., the spatiotemporal pattern) of HDRs elicited by painful stimuli. Specifically, the peak latency and the response duration were used to characterize the temporal dynamics of HDRs to painful laser stimuli and non-painful electric stimuli, and then were compared between the two conditions (i.e., pain and no-pain) using a voxel-wise univariate analysis and a multivariate pattern analysis. Furthermore, we also tested whether the two temporal characteristics of pain-elicited HDRs and their spatial patterns were associated with pain-related behaviors. We found that the spatial patterns of HDR peak latency and response duration could successfully discriminate pain from no-pain. Interestingly, we also observed that the Pain Vigilance and Awareness Questionnaire (PVAQ) scores were correlated with the average response duration in bilateral insula and secondary somatosensory cortex (S2) and could also be predicted from the across-voxel spatial patterns of response durations in the middle cingulate cortex and middle frontal gyrus only during painful condition but not during non-painful condition. These findings indicate that the spatiotemporal pattern of pain-elicited HDRs may contain pain-specific information and highlight the importance of studying the neural mechanisms of pain by taking advantage of the high sensitivity of fMRI to both spatial and temporal information of brain responses.

Neonatal neural responses to novelty related to behavioral inhibition at 1 year.

Behavioral inhibition (BI), an early-life temperament characterized by vigilant responses to novelty, is a risk factor for anxiety disorders. In this study, we investigated whether differences in neonatal brain responses to infrequent auditory stimuli relate to children's BI at 1 year of age. Using functional magnetic resonance imaging (fMRI), we collected blood-oxygen-level-dependent (BOLD) data from N = 45 full-term, sleeping neonates during an adapted auditory oddball paradigm and measured BI from n = 27 of these children 1 year later using an observational assessment. Whole-brain analyses corrected for multiple comparisons identified 46 neonatal brain regions producing novelty-evoked BOLD responses associated with children's BI scores at 1 year of age. More than half of these regions (n = 24, 52%) were in prefrontal cortex, falling primarily within regions of the default mode or frontoparietal networks or in ventromedial/orbitofrontal regions without network assignments. Hierarchical clustering of the regions based on their patterns of association with BI resulted in two groups with distinct anatomical, network, and response-timing profiles. The first group, located primarily in subcortical and temporal regions, tended to produce larger early oddball responses among infants with lower subsequent BI. The second group, located primarily in prefrontal cortex, produced larger early oddball responses among infants with higher subsequent BI. These results provide preliminary insights into brain regions engaged by novelty in infants that may relate to later BI. The findings may inform understanding of anxiety disorders and guide future research. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Vaping and smoking cue reactivity in young adult non-smoking electronic cigarette users: A functional neuroimaging study.

The rapid growth in the use of electronic cigarettes (e-cigarettes) among non-smoking young adults is concerning, as it raises the potential for chronic vaping and nicotine addiction. A key characteristic of drug addiction is the elevated neural response to conditioned drug-related cues (i.e., cue reactivity). Generalized reactivity to both vaping and smoking cues may signify an increased risk for smoking initiation in non-smoking vapers. In this study, we used functional magnetic resonance imaging (fMRI) to evaluate brain responses to vaping and smoking cues in young adult non-smoking vapers. Sixty-six young adult non-smoking vapers underwent functional MRI while viewing visual cues pertaining to vaping, smoking, and nicotine-unrelated unconditioned reward (i.e., food). A priori region-of-interest analysis combined with exploratory whole-brain analysis was performed to characterize neural reactivity to vaping and smoking cues in comparison to food cues. The medial prefrontal cortex and the posterior cingulate cortex, regions that play a key role in drug cue reactivity, showed significantly increased neural response to vaping cues compared to food cues. The posterior cingulate cortex additionally showed increased neural responses to smoking cues compared to food cues. Despite not currently smoking combustible cigarettes, young adult vapers exhibited heightened neural susceptibility to both vaping and smoking cues within brain systems associated with cue reactivity. The findings shed light on the mechanisms underlying nicotine addiction and smoking initiation risk in this critical population and may contribute to the development of science-based interventions and regulatory measures in the future. The escalating vaping prevalence among US non-smoking young adults is alarming, due to its potential ramifications for nicotine addiction development. Nicotine addiction is characterized by elevated neural response to conditioned nicotine-related cues. Using functional neuroimaging, we showed that young adult non-smoking vapers exhibited heightened neural susceptibility to both vaping and smoking cues within brain systems previously associated with cue reactivity. Such cross-reactivity to both types of nicotine cues may serve as the mechanism underlying nicotine addiction and smoking initiation risk in this population. Our findings may contribute to the development of science-based interventions and regulatory measures addressing the vaping epidemic.

The Utility of Electroencephalograhy in Guiding General Anesthesia in Children.

Traditional pediatric anesthetic dosing using pharmacokinetic estimates based on age and weight is often imprecise, frequently leading to oversedation. Intraoperative electroencephalography (EEG) allows visualization of the brain's response to anesthetic agents in real time, facilitating precise titration of anesthetic drug doses optimized for the individual child. The goal of EEG-guided anesthesia management is to maintain an optimal state of hypnosis during various stages of the procedure while minimizing hemodynamic instability and other adverse effects of anesthesia. This is especially important in children with less predictable anesthetic requirements, such as children with atypical neurodevelopment, altered levels of consciousness before anesthesia, or those receiving total intravenous anesthesia, neuromuscular blockers, or a combination of anesthetic agents with different mechanisms of actions. Children with limited cardiorespiratory reserves and those undergoing high-risk procedures such as cardiopulmonary bypass also benefit from EEG guidance as they have a narrower therapeutic window for optimal anesthetic dosing. Various processed EEG (pEEG) monitors are available for intraoperative monitoring in children. These monitors display a pEEG index based on the manufacturer's algorithm, purportedly indicating the patient's hypnotic state. Due to differences in developmental neurophysiology and EEG dynamics in children, pEEG indices may not always reliably indicate the hypnotic state, especially in neonates and infants. Learning to interpret nonproprietary EEG parameters including the raw EEG, spectral-edge frequency 95% (SEF95), and density spectral array can prevent overreliance on pEEG indices. This review provides an overview of the advantages of EEG guidance during clinical anesthesia, including potential reduction in anesthetic dosage, prevention of EEG suppression, and reduction in peri-operative adverse events. We describe the use of nonproprietary EEG parameters in guiding anesthesia in children for various clinical end points including laryngoscopy, surgical incision, and maintenance of anesthesia, as well as sedation. We illustrate these principles with various case examples commonly encountered during pediatric anesthesia. Lastly, we discuss strategies to expand intraoperative EEG monitoring in children through education and training programs, as well as advocate for further research to assess clinical outcomes associated with EEG guidance to support its routine use in clinical care.