Processing In Healthy Subjects Research Articles

Linking Affect Dynamics and Well-Being: A Novel Methodological Approach for Mental Health.

Emotions are dynamic processes; their variability relates to psychological well-being and psychopathology. Affective alterations have been linked to mental diseases like depression, although little is known about how similar patterns occur in healthy individuals. This study investigates the psychophysiological correlations of emotional processing in healthy subjects, specifically exploring the relationship between depressive traits, cognitive distortions, and facial electromyographic (f-EMG) responses during affective transitions. A cohort of 44 healthy participants underwent f-EMG recording while viewing emotional images from the International Affective Picture System (IAPS). Self-report measures included the Beck Depression Inventory (BDI) and the Cognitive Distortion Scale (CDS). Higher BDI scores were associated with increased EMG activity in the corrugator muscle during transitions between positive and negative emotional states. Cognitive distortions such as Catastrophizing, All-or-Nothing Thinking, and Minimization showed significant positive correlations with EMG activity, indicating that individuals with higher levels of these distortions experienced greater facial muscle activation during emotional transitions. This study's results indicate that there is a bidirectional correlation between depressed features and cognitive distortions and alterations in facial emotional processing, even in healthy subjects. Facial EMG in the context of dynamic affective transitions has the potential to be used as a non-invasive method for detecting abnormal emotional reactions at an early stage. This might help in identifying individuals who are at risk of developing depression and guide therapies to prevent its advancement.

Vagus nerve stimulation during training fails to improve learning in healthy rats

Learning new skills requires neuroplasticity. Vagus nerve stimulation (VNS) during sensory and motor events can increase neuroplasticity in networks related to these events and might therefore serve to facilitate learning on sensory and motor tasks. We tested if VNS could broadly improve learning on a wide variety of tasks across different skill domains in healthy, female adult rats. VNS was paired with presentation of stimuli or on successful trials during training, strategies known to facilitate plasticity and improve recovery in models of neurological disorders. VNS failed to improve either rate of learning or performance for any of the tested tasks, which included skilled forelimb motor control, speech sound discrimination, and paired-associates learning. These results contrast recent findings from multiple labs which found VNS pairing during training produced learning enhancements across motor, auditory, and cognitive domains. We speculate that these contrasting results may be explained by key differences in task designs, training timelines and animal handling approaches, and that while VNS may be able to facilitate rapid and early learning processes in healthy subjects, it does not broadly enhance learning for difficult tasks.

Transcranial Direct Current Stimulation (tDCS) Effects on Quantitative Sensory Testing (QST) and Nociceptive Processing in Healthy Subjects: A Systematic Review and Meta-Analysis.

The aim of this study is to determine the effect that different tDCS protocols have on pain processing in healthy people, assessed using quantitative sensory tests (QST) and evoked pain intensity. We systematically searched in EMBASE, CINAHL, PubMed, PEDro, PsycInfo, and Web of Science. Articles on tDCS on a healthy population and regarding QST, such as pressure pain thresholds (PPT), heat pain thresholds (HPT), cold pain threshold (CPT), or evoked pain intensity were selected. Quality was analyzed using the Cochrane Risk of Bias Tool and PEDro scale. Twenty-six RCTs were included in the qualitative analysis and sixteen in the meta-analysis. There were no significant differences in PPTs between tDCS and sham, but differences were observed when applying tDCS over S1 in PPTs compared to sham. Significant differences in CPTs were observed between tDCS and sham over DLPFC and differences in pain intensity were observed between tDCS and sham over M1. Non-significant effects were found for the effects of tDCS on HPTs. tDCS anodic over S1 stimulation increases PPTs, while a-tDCS over DLPFC affects CPTs. The HPTs with tDCS are worse. Finally, M1 a-tDCS seems to reduce evoked pain intensity in healthy subjects.

Effects of a single dose of amisulpride on functional brain changes during reward- and motivation-related processing using task-based fMRI in healthy subjects and patients with major depressive disorder — study protocol for a randomized clinical trial

BackgroundAnhedonia and other deficits in reward- and motivation-related processing in psychiatric patients, including patients with major depressive disorder (MDD), represent a high unmet medical need. Neurobiologically, these deficits in MDD patients are mainly associated with low dopamine function in a frontostriatal network. In this study, alterations in brain activation changes during reward processing and at rest in MDD patients compared with healthy subjects are explored and the effects of a single low dose of the dopamine D2 receptor antagonist amisulpride are investigated.MethodsThis is a randomized, controlled, double-blind, single-dose, single-center parallel-group clinical trial to assess the effects of a single dose of amisulpride (100 mg) on blood-oxygenation-level-dependent (BOLD) responses during reward- and motivation-related processing in healthy subjects (n = 60) and MDD patients (n = 60). Using functional magnetic resonance imaging (fMRI), BOLD responses are assessed during the monetary incentive delay (MID) task (primary outcome). Exploratory outcomes include BOLD responses and behavioral measures during the MID task, instrumental learning task, effort-based decision-making task, social incentive delay task, and probabilistic reward task as well as changes in resting state functional connectivity and cerebral blood flow.DiscussionThis study broadly covers all aspects of reward- and motivation-related processing as categorized by the National Institute of Mental Health Research Domain Criteria and is thereby an important step towards precision psychiatry. Results regarding the immediate effects of a dopaminergic drug on deficits in reward- and motivation-related processing not only have the potential to significantly broaden our understanding of underlying neurobiological processes but might eventually also pave the way for new treatment options.Trial registrationClinicalTrials.gov NCT05347199. April 12, 2022.

Theory of visual attention (TVA) applied to rats performing the 5-choice serial reaction time task: differential effects of dopaminergic and noradrenergic manipulations

RationaleAttention is compromised in many psychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD). While dopamine and noradrenaline systems have been implicated in ADHD, their exact role in attentional processing is yet unknown.ObjectivesWe applied the theory of visual attention (TVA) model, adapted from human research, to the rat 5-choice serial reaction time task (5CSRTT) to investigate catecholaminergic modulation of visual attentional processing in healthy subjects of high- and low-attention phenotypes.MethodsRats trained on the standard 5CSRTT and tested with variable stimulus durations were treated systemically with noradrenergic and/or dopaminergic agents (atomoxetine, methylphenidate, amphetamine, phenylephrine and atipamezole). TVA modelling was applied to estimate visual processing speed for correct and incorrect visual perceptual categorisations, independent of motor reaction times, as measures of attentional capacity.ResultsAtomoxetine and phenylephrine decreased response frequencies, including premature responses, increased omissions and slowed responding. In contrast, methylphenidate, amphetamine and atipamezole sped up responding and increased premature responses. Visual processing speed was also affected differentially. Atomoxetine and phenylephrine slowed, whereas methylphenidate and atipamezole sped up, visual processing, both for correct and incorrect categorisations. Amphetamine selectively improved visual processing for correct, though not incorrect, responses in high-attention rats only, possibly reflecting improved attention.ConclusionsThese data indicate that the application of TVA to the 5CSRTT provides an enhanced sensitivity to capturing attentional effects. Unexpectedly, we found overall slowing effects, including impaired visual processing, following drugs either increasing extracellular noradrenaline (atomoxetine) or activating the α1-adrenoceptor (phenylephrine), while also ameliorating premature responses (impulsivity). In contrast, amphetamine had potential pro-attentional effects by enhancing visual processing, probably due to central dopamine upregulation.

Gut Feelings: Vagal Stimulation Reduces Emotional Biases

The vagus nerve is a key physical constituent of the gut–brain axis. Increasing attention has recently been paid to the role that the gut, and the microorganisms inhabiting it, play in emotion and cognition. Animal studies have revealed the importance of the vagus nerve in mediating communication between the gut microbiome and the central nervous system, resulting in changes in emotional behaviour. This has renewed interest in understanding the role of vagal signalling in human emotion, particularly since human studies have also shown that alterations in gut microbiome composition can affect emotion. While stimulating the vagus nerve can help treat some cases of severe depression, here we investigate whether vagal afferent signalling can influence emotional processing in healthy subjects. We use the dot-probe task to determine the effect of transcutaneous vagus nerve stimulation on attentional biases towards emotional stimuli in 42 volunteers. Participants received both active and sham treatments using a within-subject design. We show that transcutaneous vagus nerve stimulation reduces the emotional bias towards faces expressing sadness and happiness, indicating a decrease in emotional reactivity. While our novel findings reveal the effect that vagal signalling can have on emotional biases in healthy subjects, future studies should seek to develop our understanding of the ways in which the microbiome interacts with, and stimulates, the vagus nerve. Since we find a reduction in emotional bias, most notably towards sadness, this may partly account for the effective use of vagus nerve stimulation in treatment-resistant depression. While its clinical application currently involves surgical stimulation, our results support the potential benefit of transcutaneous vagus nerve stimulation as a non-invasive, intermittent adjunctive therapy for patients with depression, given its frequent association with emotional biases.

Surface Electromyography Quantification Methods for Evaluating Muscle Activity in Dysphagia

Quantitative evaluation of stroke patients with the risk of swallowing disorder or dysphagia is required to support diagnosis and further rehabilitation planning. Fluoroscopy X-ray imaging usually is used for swallowing diagnosis, though it gives radiation exposure to patients. Therefore, quantification of muscle coordination patterns involved in swallowing based on surface electromyography (sEMG) was introduced. However, an adequate quantification of sEMG for dysphagia diagnosis still lacks standardization. In this work, potential sEMG signal features, namely the contraction duration (DUR), the time to peak of maximum contraction (TTP), and the total RMS power (TP), were further investigated to evaluate the swallowing processes in healthy subjects and post-stroke patients. The experimental scheme instructed the participant, i.e. 20 healthy subjects and 20 patients, to swallow 3 mL of water in normal swallowing mode and swallow saliva in dry swallowing mode. The proposed signal processing procedure helps to establish the feature extraction of the three features mentioned earlier. For dysphagia assessment, with the support of our proposed signal processing procedure, DUR and TTP can be used together to improve diagnosis reliability. The characteristic of both features in healthy subjects was shorter than in post-stroke patients. Also, the TP feature is useful as additional information to evaluate the role of suprahyoid (SUP) and infrahyoid (INF) muscle groups which are very important in the swallowing process. These results are promising to provide a reliable set of features in the time domain for swallowing analysis. Notably, this can also be utilized as a feature for supporting the automatic classification of dysphagia diagnosis.

The effects of psychosocial and cognitive stress on executive functions and automatic processes in healthy subjects: A pilot study

The main aim of the present study was to examine the effects of psychosocial and cognitive stress on executive functions and automatic processes in healthy subjects. To achieve these purposes, we investigated whether cognitive stress impaired the controlled processing underlying cognitive flexibility, working memory and initial letter fluency performances, and whether social stress impaired both performance of executive processes and of semantic fluency. We employed the psychosocial stress paradigm in which cognitive assessment was superimposed on cognitive and social stressors soon after their introduction and was carried out concurrently while they were present. With reference to cognitive stress, we employed the dual-task paradigm that involves a primary task (performances related to executive functions and automatic task) and a secondary task (focusing attention and memorizing items in another cognitive task). Eighty-eight healthy subjects, between 18 and 30 years, participated in this study. They were randomly divided into three groups: two groups undergoing a stress procedure, respectively a cognitive stress group and a social stress group, and a control group. Results indicated that stress impaired cognitive flexibility, working memory and verbal fluency. Cognitive flexibility was affected to a greater extent by psychosocial stress than cognitive stress. This study suggests that the negative effects of stress on cognitive flexibility may be a consequence of the interplay between controlled and automatic processes.

Modulatory Effects of Memantine on Neuronal Response Properties in Rat Barrel Cortex.

Introduction:Memantine as N-Methyl-D-Aspartic Acid (NMDA) receptor antagonist is used in some neurological disorders. Moreover, memantine presents modulatory effects on the somatosensory information processing in healthy subjects. This study investigated the effects of memantine on electrophysiological properties of barrel cortex neurons in male rats.Methods:Single unit recording was used to evaluate the electrophysiological properties of barrel cortex neurons. The neural responses to the Principal Whisker (PW), Adjacent Whisker (AW), and combined displacement of two whiskers [20 ms Inter-Stimulus Intervals (ISIs)] were recorded before and 2 hours after memantine gavage (10 mg/kg). A Condition Test Ratio (CTR) was calculated for assessing inhibitory interactions.Results:Two hours after memantine gavage, neuronal ON and OFF responses to PW deflection were decreased. Furthermore, CTR for both ON and OFF responses was decreased following memantine administration.Conclusion:The current study demonstrated that memantine modified neural response properties in the rat barrel cortex.HighlightsMemantine modulated excitatory receptive fields in the rat somatosensory cortex.Memantine decreased integrative receptive fields in rat somatosensory cortex.Plain Language SummaryAs an NMDA receptor antagonist, memantine is used to treat moderate to severe Alzheimer’s disease. Memantine has beneficial effects on cognition, mood, and perform daily activities. However, the current study results suggested that memantine may affect information processing in the somatosensory system. This should be considered for future research in the clinic.

O3.2. ROBOT-INDUCED MILD HALLUCINATIONS AND PASSIVITY EXPERIENCES IN INDIVIDUALS WITH THE 22Q11.2 DELETION SYNDROME

BackgroundThe 22q11.2 deletion syndrome (22q11DS) represents one of the highest genetic risk factors for developing schizophrenia. About 30% of individuals develop symptoms like hallucinations, thought disorders, passivity symptoms or loss of agency. These symptoms could be driven by abnormal sensorimotor predictions associated with the misattribution of self-related events to external sources (Frith, 2005). We developed a robotic device altering sensorimotor processing in healthy subjects and inducing mild to moderate hallucinations (presence hallucinations - PH) and passivity experiences (Blanke et al., 2014). Using this new device and procedure, we tested the sensitivity of individuals with 22q11DS to sensorimotor conflicts provided by the robot and their proneness in experiencing robot-induced PH and related passivity experiences as compared to healthy controls.MethodsThirty-eight individuals with 22q11DS and 21 controls moved, with the hand, a robotic device placed in front of them. A second robot placed behind them reproduced their movements, thus delivering tactile feedback on their back either synchronously (0ms between the movement and the touch, sync) or asynchronously (delay of 500ms, async) (Blanke et al., 2014). Participants rated the strength of robot-induced PH, passivity experiences that they felt during robot manipulation, and control items. Occurrence and severity of clinical symptoms were assessed.ResultsSubjective ratings following robot manipulation were analysed, and age was used as covariate. In the asynch condition, participants reported significantly stronger loss of agency over their hand movements and there was a trend towards a significant interaction between group and conditions for loss of agency with control subjects experiencing more loss of agency in the asynchronous condition than 22q11DS participants. A trend for significance was also observed whereby all subjects reported stronger PH in the asynchronous condition than in the synchronous condition. No significant group effect was observed for the subjective ratings associated with the robot manipulation. For the 22q11DS group, severity scores for items of unusual thought content/delusional ideas of the Structured Interview for Prodromal Syndromes positively and significantly correlated with ratings of robot-induced PH and loss of agency in the async condition. Passivity experiences during the async condition (i.e., the subjective impression that someone else was touching their back) significantly correlated with severity scores for perceptual abnormalities/hallucinations items.DiscussionExperimental induction of sensorimotor conflicts caused mild altered mental states in individuals with 22q11DS as reported for controls. Both 22q11DS and control groups showed more sensitivity to the asynchronous condition during which they perceived loss of agency and passivity over their own actions, suggesting that the robotic stimulations disrupted self-other demarcation. In 22q11DS individuals, induced-PH, passivity experiences and loss of agency felt during the robot manipulation was associated to unusual thought content and abnormal perception. Taken together, our results suggest that 22q11DS is an interesting model to study the development of prodromal signs of psychosis at a very early stage before the onset of schizophrenia.

BOLD differences normally attributed to inhibitory control predict symptoms, not task-directed inhibitory control in ADHD

BackgroundAltered brain activity that has been observed in attention deficit hyperactivity disorder (ADHD) while performing cognitive control tasks like the stop signal task (SST) has generally been interpreted as reflecting either weak (under-active) or compensatory (over-active) versions of the same functions as in healthy controls. If so, then regional activities that correlate with the efficiency of inhibitory control (i.e. stop signal reaction time, SSRT) in healthy subjects should also correlate with SSRT in ADHD. Here we test the alternate hypothesis that BOLD (blood-oxygen-level-dependent) differences might instead reflect the redirection of neural processing resources normally used for task-directed inhibitory control, towards actively managing symptomatic behaviour. If so, then activities that correlate with SSRT in TD should instead correlate with inattentive and hyperactive symptoms in ADHD.MethodsWe used fMRI (functional magnetic resonance imaging) in 14 typically developing (TD) and 14 ADHD adolescents performing the SST, and in a replication sample of 14 healthy adults. First, we identified significant group BOLD differences during all phases of activity in the SST (i.e. warning, response, reactive inhibition, error detection and post-error slowing). Next, we correlated these phases of activity with SSRT in TD and with SSRT, inattentive and hyperactive symptom scores in ADHD. We then identified whole brain significant correlations in regions of significant group difference in activity.ResultsOnly three regions of significant group difference were correlated with SSRT in TD and replication groups (left and right inferior frontal gyri (IFG) during error detection and hypothalamus during post-error slowing). Consistent with regions of altered activity managing symptomatic behaviour instead of task-directed behaviour, left IFG correlated with greater inattentive score, right IFG correlated with lower hyperactive score and hypothalamus correlated with greater inattentive score and oppositely correlated with SSRT compared to TD.ConclusionsStimuli that elicit task-directed integration of neural processing in healthy subjects instead appear to be directing integrated function towards managing symptomatic behaviour in ADHD. The ability of the current approach to determine whether altered neural activities reflect comparable functions in ADHD and control groups has broad implications for the development and monitoring of therapeutic interventions.

The opportunity of application of neurophysiological tests — schizophrenia endophenotypes for studying the role of genetic factors in cognitive processes in healthy subjects and in psychiatric diseases

The study of effects of genetic polymorphisms implicated in dopamine (COMT, DRD2) and GABA (GAD1) activities in the prefrontal cortex on antisaccades (AS) and evoked potential P300 measures was conducted with participation of 55 healthy subjects and 72 schizophrenic patients. The significant interaction of genotype and disease was found for most of the studied AS and P300 measures. The worse task performance and decreased efficacy of cortical activation were revealed for the associated with schizophrenia risk polymorphisms.

A Handwriting-Based Protocol for Assessing Neurodegenerative Dementia

Handwriting dynamics is relevant to discriminate people affected by neurodegenerative dementia from healthy subjects. This can be possible by administering simple and easy-to-perform handwriting/drawing tasks on digitizing tablets provided with electronic pens. Encouraging results have been recently obtained; however, the research community still lacks an acquisition protocol aimed at (i) collecting different traits useful for research purposes and (ii) supporting neurologists in their daily activities. This work proposes a handwriting-based protocol that integrates handwriting/drawing tasks and a digitized version of standard cognitive and functional tests already accepted, tested, and used by the neurological community. The protocol takes the form of a modular framework which facilitates the modification, deletion, and incorporation of new tasks in accordance with specific requirements. A preliminary evaluation of the protocol has been carried out to assess its usability. Successively, the protocol has been administered to more than 100 elderly MCI and match controlled subjects. The proposed protocol intends to provide a “cognitive model” for evaluating the relationship between cognitive functions and handwriting processes in healthy subjects as well as in cognitively impaired patients. The long-term goal of this research is the development of an easy-to-use and non-invasive methodology for detecting and monitoring neurodegenerative dementia during screening and follow-up.

What a pooled data study tells us about the relationships between gender and knowledge of semantic categories

ABSTRACTIntroduction: Both the neuropsychological study of patients with category-specific semantic disorders (CSSD) and the experimental research on categorical processing in healthy subjects (HSs) have shown that men are mainly impaired with fruits and vegetables and women with animals and artifacts. Since this difference is more striking in patients with CSSD than in HSs, we hypothesized that the lack of power of some investigations conducted with HSs and the different methods used in studies conducted with HSs and patients with CSSD could explain some of these inconsistencies and that a study conducted with a very large number of HSs using visual naming tasks should strongly confirm the role of gender in categorical tasks.Methods: Picture naming data gathered during the last ten years with our category-specificity paradigm from a large number (702) of HSs were reanalyzed.Results: As predicted, men named significantly more animals and artifacts, while women named more plant life items.Discussion: These data confirm that, if different domains of knowledge are studied in a very large sample of HSs using a picture naming task equivalent to the naming tasks used in most anatomo-clinical studies on CSSD, then the gender effects are highly significant.

The Y-shaped trabecular bone structure in the odontoid process of the axis: a CT scan study in 54 healthy subjects and biomechanical considerations.

Odontoid process fractures are very common in both young and geriatric patients. The axial trabecular architecture of the dens appears to be crucial for physiological and biomechanical function of the C1-2 joint. The aim of this study is to demonstrate the presence of a Y-shaped trabecular structure of the dens on axial CT and to describe its anatomical and biomechanical implications. Fifty-four C2 odontoid processes in healthy subjects were prospectively examined for the presence of a Y-shaped trabecular structure at the odontocentral synchondrosis level with a dental cone beam CT scan. Length, width, and axial area of the odontoid process were measured in all subjects. In addition, measurements of the one-third right anterior area of the Y-shaped structure were taken. The Y-shaped trabecular structure was found in 79.6% of cases. Length and width of the odontoid process were 13.5 ± 0.6 mm and 11.2 ± 0.9 mm, respectively. The mean area of the odontoid process at the odontocentral synchondrosis was 93.5 ± 4.3 mm2, whereas the mean one-third right anterior area of the odontoid process at the same level was 29.3 ± 2.5 mm2. The mean area of the odontoid process and its length and width were similar in men and women (p > 0.05). No significant difference was found in the mean area of the odontoid process in people older than 65 years (94 ± 4.2 mm2) compared to people younger than 65 years (93.3 ± 4.4 mm2; p > 0.05). The authors identified a new anatomical entity, named the Y-shaped trabecular structure of the odontoid process, on axial CT scans. This structure appears to be the result of bone transformation induced by the elevated dynamic loading at the C1-2 level. The presence of the Y-shaped structure provides new insights into biomechanical responses of C2 under physiological loading and traumatic conditions.

Measurements of Temporal Summation of Heat Pain: a Pilot Investigation in Healthy Humans

Temporal summation of pain (TSP) is a promising tool for measuring the pain modulation processes in healthy subjects and patients with chronic pain. We tried to find optimal stimulation parameters in order to elicit a robust reproducible TSP phenomenon. Twenty healthy volunteers (15 women and 5 men) completed four sessions/conditions of pulsating heat pain stimulation, applied to the left forearm with a frequency of 0.33–0.4 sec–1 using a contact heat-evoked potential stimulator. The stimulation temperature (step +0.5°C or +1.0°C up to the pain threshold, pain tolerance), pulse duration (500, 800, or 1000 msec), and number of stimuli (60 or 90) were varied. The participants rated the pain intensity at the first and every 10th heat pulse, using a numeric rating scale (NRS) 0–100. The TSP was calculated as the difference between the lowest rating and the rating of the last stimulus and was compared between conditions. The optimal condition (19 out of 20 participants responded with TSP) showed temperature at pain tolerance, pulse duration of 800 msec, and 90 stimuli. In addition, this condition showed weaker side effects (painful discomfort) than those with less (60) but longer (1000 msec) stimuli presented 1.0 degree above the pain threshold. The protocol with a relatively high stimulus repetition and a moderate pulse duration seems to be the optimal protocol to reproduce TSP. Heat stimulation with longer pulse durations and higher stimulation temperatures was less feasible.

Quantification of the Central Cardiovascular Network Applying the Normalized Short-time Partial Directed Coherence Approach in Healthy Subjects.

The central control of the autonomic nervous system (ANS) and the complex interplay of its components can be described by a functional integrated mode - the central autonomic network (CAN). CAN represents the integrated functioning and interaction between the central nervous system (CNS) and ANS (parasympathetic and sympathetic activity). This study investigates the central cardiovascular network (CCVN) as a part of the CAN, during which heart rate (HR), systolic blood pressure (SYS) and frontal EEG activity in 21 healthy subjects (CON) will be analysed. The objective of this study is to determine how these couplings (central-cardiovascular) are composed by the different regulatory aspects of the CNS-ANS interaction. To quantify the short-term instantaneous causal couplings within the CCVN, the normalized short time partial directed coherence (NSTPDC) approach was applied. It is based on an m-dimensional MAR process to determine Granger causality in the frequency domain. We found that CCVN were of bidirectional character, and that the causal influences of central activity towards HR were stronger than those towards systolic blood pressure. This suggests that the central-cardiac closed-loop regulation process in CON focuses mainly on adapting the heart rate via the sinoatrial node rather than focusing on SYS. The CNS-ANS coupling directions with respect to central spectral power bands were characterized as mostly bidirectional, where HR and SYS acted as drivers in nearly every frequency band (unidirectional for α, α1 and α2). This study provides a more indepth understanding of the interplay of neuronal and autonomic cardiovascular regulatory processes in healthy subjects, as well as a greater insight into the complex CAN.

Vowel-speech versus pure-tone processing in healthy subjects

To investigate the characteristics of speech perception, we evaluated the differences in mismatch negativity (MMN) between vowel change and frequency change. Additionally, we examined the effects of gender, age, and educational length on MMN. Forty healthy adults (21 females), who were native Japanese speakers, participated in the study. A Japanese vowel-speech pair (standard/a/vs. deviant/o/) and a pure-tone pair (standard 1000 Hz vs. deviant 1050 Hz) were constructed. MMN elicited by vowel-speech sounds was larger and earlier compared with pure-tone sounds. Larger and earlier MMNs for vowel-speech sounds than for pure-tone sounds suggest different processing of linguistically relevant information at the early stage in the auditory cortex. In conclusion, the factors influencing on MMN are different between vowel-speech sounds and pure-tone sounds.

Neural substrates of the emotion-word and emotional counting Stroop tasks in healthy and clinical populations: A meta-analysis of functional brain imaging studies

The emotional Stroop task (EST) is among the most influential paradigms used to probe attention-related or cognitive control-related emotional processing in healthy subjects and clinical populations. The neuropsychological mechanism underlying the emotional Stroop effect has attracted extensive and long-lasting attention in both cognitive and clinical psychology and neuroscience; however, a precise characterization of the neural substrates underlying the EST in healthy and clinical populations remains elusive. Here, we implemented a coordinate-based meta-analysis covering functional imaging studies that employed the emotion-word or emotional counting Stroop paradigms to determine the underlying neural networks in healthy subjects and the trans-diagnostic alterations across clinical populations. Forty-six publications were identified that reported relevant contrasts (negative > neutral; positive > neutral) for healthy or clinical populations as well as for hyper- or hypo-activation of patients compared to controls. We demonstrate consistent involvement of the vlPFC and dmPFC in healthy subjects and consistent involvement of the vlPFC in patients. We further identify a trans-diagnostic pattern of hyper-activation in the prefrontal and parietal regions. These findings underscore the critical roles of cognitive control processes in the EST and implicate trans-diagnostic cognitive control deficits. Unlike the current models that emphasize the roles of the amygdala and rACC, our findings implicate novel mechanisms underlying the EST for both healthy and clinical populations.

Food-related salience processing in healthy subjects during word recognition: Fronto-parietal network activation as revealed by independent component analysis.

BackgroundThe study aimed to isolate and localize mutually independent cognitive processes evoked during a word recognition task involving food‐related and food‐neutral words using independent component analysis (ICA) for continuously recorded EEG data. Recognition memory (old/new effect) involves cognitive subcomponents—familiarity and recollection—which may be temporally and spatially dissociated in the brain. Food words may evoke additional attentional salience which may interact with the old/new effect.MethodsSixteen satiated female participants undertook a word recognition task consisting of an encoding phase (learning of presented words, 40 food‐related and 40 food neutral) and a test phase (recognition of previously learned words and new words). Simultaneously recorded 64‐channel EEG data were decomposed into mutually independent components using the Infomax algorithm in EEGLAB. The components were localized using single dipole fitting using a four‐shell BESA head model. The resulting (nonartefactual) components with <15% residual variance were clustered across subjects using the kmeans algorithm resulting in five meaningful clusters localized to fronto‐parietal regions. Repeated‐measures anova was employed to test main effects (old/new and food relevance) and their interaction on cluster time courses.ResultsEarly task‐relevant old/new effects were localized to the medial frontal gyrus (MFG) and later old/new effects to the right parietal regions (precuneus). Food‐related (nontask‐relevant) salience effects were localized to bilateral parietal regions (left precuneus and right postcentral gyrus). Food‐related salience interacted with task relevance, the old/new effect in MFG being significant only for food‐neutral words highlighting central the role of MFG as the converging site of endogenous and exogenous salience inputs.ConclusionOur results indicate ICA to be a valid technique to decompose complex neurophysiological signals involving multiple cognitive processes and implicate the fronto‐parietal network as an important attentional network for processing salience and task demands.