Neuronal correlates of spider phobia in a combined fNIRS-EEG study

Neural correlates of recalled sadness, joy, and fear states: a source reconstruction EEG study

Introduction

The capacity to understand the others' emotional states, particularly if negative (e.g. sadness or fear), underpins the empathic and social brain. Patients who cannot express their emotional states experience social isolation and loneliness, exacerbating distress. We investigated the feasibility of detecting non-invasive scalp-recorded electrophysiological signals that correspond to recalled emotional states of sadness, fear, and joy for potential classification.

Methods

The neural activation patterns of 20 healthy and right-handed participants were studied using an electrophysiological technique. Analyses were focused on the N400 component of Event-related potentials (ERPs) recorded during silent recall of subjective emotional states; Standardized weighted Low-resolution Electro-magnetic Tomography (swLORETA) was employed for source reconstruction. The study classified individual patterns of brain activation linked to the recollection of three distinct emotional states into seven regions of interest (ROIs).

Results

Statistical analysis (ANOVA) of the individual magnitude values revealed the existence of a common emotional circuit, as well as distinct brain areas that were specifically active during recalled sad, happy and fearful states. In particular, the right temporal and left superior frontal areas were more active for sadness, the left limbic region for fear, and the right orbitofrontal cortex for happy affective states.

Discussion

In conclusion, this study successfully demonstrated the feasibility of detecting scalp-recorded electrophysiological signals corresponding to internal and subjective affective states. These findings contribute to our understanding of the emotional brain, and have potential applications for future BCI classification and identification of emotional states in LIS patients who may be unable to express their emotions, thus helping to alleviate social isolation and sense of loneliness.

Exploring the neural basis and modulating factors of implicit altercentric spatial perspective-taking with fNIRS

Humans spontaneously take the perspective of others when encoding spatial information in a scene, especially with agentive action cues present. This functional near-infrared spectroscopy (fNIRS) study explored how action observation influences implicit spatial perspective-taking (SPT) by adapting a left-right spatial judgment task to investigate whether transformation strategies underlying altercentric SPT can be predicted on the basis of cortical activation. Strategies associated with two opposing neurocognitive accounts (embodied versus disembodied) and their proposed neural correlates (human mirror neuron system; hMNS versus cognitive control network; CCN) are hypothesized. Exploratory analyses with 117 subjects uncover an interplay between perspective-taking and post-hoc factor, consistency of selection, in regions alluding to involvement of the CCN. Descriptively, inconsistent altercentric SPT elicited greater activation than consistent altercentric SPT and/or inconsistent egocentric SPT in the left inferior frontal gyrus (IFG), left dorsolateral prefrontal cortex (DLPFC) and left motor cortex (MC), but not the inferior parietal lobules (IPL). Despite the presence of grasping cues, spontaneous embodied strategies were not evident during implicit altercentric SPT. Instead, neural trends in the inconsistent subgroups (22 subjects; 13 altercentric; 9 egocentric) suggest that inconsistency in selection modulates the decision-making process and plausibly taps on deliberate and effortful disembodied strategies driven by the CCN. Implications for future research are discussed.

Toward a reliable detection of arachnophobia: subjective, behavioral, and neurophysiological measures of fear response

Introduction

The administration of questionnaires presents an easy way of obtaining important knowledge about phobic patients. However, it is not well known how these subjective measurements correspond to the patient's objective condition. Our study aimed to compare scores on questionnaires and image evaluation to the objective measurements of the behavioral approach test (BAT) and the neurophysiological effect of spiders extracted from fMRI measurements. The objective was to explore how reliably subjective statements about spiders and physiological and behavioral parameters discriminate between phobics and non-phobics, and what are the best predictors of overall brain activation.

Methods

Based on a clinical interview, 165 subjects were assigned to either a "phobic" or low-fear "control" group. Finally, 30 arachnophobic and 32 healthy control subjects (with low fear of spiders) participated in this study. They completed several questionnaires (SPQ, SNAQ, DS-R) and underwent a behavioral approach test (BAT) with a live tarantula. Then, they were measured in fMRI while watching blocks of pictures including spiders and snakes. Finally, the respondents rated all the visual stimuli according to perceived fear. We proposed the Spider Fear Index (SFI) as a value characterizing the level of spider fear, computed based on the fMRI measurements. We then treated this variable as the "neurophysiological effect of spiders" and examined its contribution to the respondents' fear ratings of the stimuli seen during the fMRI using the redundancy analysis (RDA).

Results

The results for fear ranks revealed that the SFI, SNAQ, DS-R, and SPQ scores had a significant effect, while BAT and SPQ scores loaded in the same direction of the first multivariate axis. The SFI was strongly correlated with both SPQ and BAT scores in the pooled sample of arachnophobic and healthy control subjects.

Discussion

Both SPQ and BAT scores have a high informative value about the subject's fear of spiders and together with subjective emotional evaluation of picture stimuli can be reliable predictors of spider phobia. These parameters provide easy and non-expensive but reliable measurement wherever more expensive devices such as magnetic resonance are not available. However, SFI still reflects individual variability within the phobic group, identifying individuals with higher brain activation, which may relate to more severe phobic reactions or other sources of fMRI signal variability.

A Neurobiological Profile Underlying Comorbidity Load and Prospective Increases in Dysphoria in a Focal Fear Sample

BACKGROUND

Knowledge of the neural mechanisms underlying increased disease burden in anxiety disorders that is unaccounted for by individual categorical diagnoses could lead to improved clinical care. Here, we tested the utility of a joint functional magnetic resonance imaging-electroencephalography neurobiological profile characterized by overvaluation of negative stimuli (amygdala) in combination with blunted elaborated processing of these same stimuli (the late positive potential [LPP], an event-related potential) in predicting increased psychopathology across a 2-year period in people with anxiety disorders.

METHODS

One hundred ten participants (64 female, 45 male, 1 other) including 78 participants with phobias who varied in the extent of their internalizing comorbidity and 32 participants who were free from psychopathology viewed negative and neutral pictures during separate functional magnetic resonance imaging blood oxygen level-dependent and electroencephalogram recordings. Dysphoria was assessed at baseline and 2 years later.

RESULTS

Participants with both heightened amygdala activation and blunted LPPs to negative pictures showed the greatest increases in dysphoria 2 years later. Cross-sectionally, participants with higher comorbidity load (≥2 additional diagnoses, n = 34) showed increased amygdala activation to negative pictures compared with participants with lower comorbidity load (≤1 additional diagnosis, n = 44) and compared with participants free from psychopathology. In addition, high comorbid participants showed reduced LPPs to negative pictures compared with low comorbid participants.

CONCLUSIONS

Heightened amygdala in response to negative stimuli in combination with blunted LPPs could indicate overvaluation of threatening stimuli in the absence of elaborated processing that might otherwise help regulate threat responding. This brain profile could underlie the worsening and maintenance of internalizing psychopathology over time.

Does context matter in misophonia? A multi-method experimental investigation

Introduction

Misophonia is a recently defined disorder in which certain aversive repetitive sounds and associated stimuli elicit distressing and impairing affective, behavioral, and physiological responses. The responses in misophonia may be stronger when the sound is produced by close friends and family, suggesting that the context in which a triggering cue occurs may have an important role in misophonia. As such, the goal of this study was to test experimentally whether the context of the sound source influences affective and psychophysiological responses to triggering stimuli in misophonia.

Methods

Sixty one adults with misophonia and 45 controls listened to audio recordings (8 s) of human eating, animals eating, and human mouth smacking sounds (without eating). After a break, the same audio recordings were presented embedded within videos of human eating (congruent stimuli), animals eating (congruent stimuli), and, in the mouth smacking condition, with visually incongruent stimuli (hands playing in mud or in a bowl with a watery dough). Psychophysiological responses-skin conductance response (SCR) and heart rate (HR), and self-reported affective responses (valence, arousal, dominance) were gathered during the experiment in a laboratory.

Results

Participants with misophonia assessed all the stimuli as more negative and arousing than the controls, and reported feeling less dominant with respect to the sounds. Animal and mouth smacking sounds were assessed by all the participants as less negative and arousing than human eating sounds, but only in the audio-video conditions. SCR data partially confirmed increased psychophysiological arousal in misophonia participants during an exposure to mouth sounds, but did not reflect the self-report changes in response to different contexts. Misophonia participants had deeper deceleration of HR than controls during human eating sound with congruent video stimuli, while there was no group difference during human mouth smacking with incongruent video stimuli.

Conclusion

Results suggest that the context of mouth sounds influences affective experiences in adults with misophonia, but also in participants without misophonia. Presentation of animal eating sounds with congruent visual stimuli, or human mouth smacking sounds with incongruent stimuli, decreased self-report reaction to common misophonic triggers.

Behavioral and electrophysiological analyses of self-referential neural processing in major depressive disorder

Cognitive theories suggest that patients with major depressive disorder (MDD) constantly negatively evaluate their self-referential information. Unlike Westerners with an independent self, self-representation is strongly influenced by cultural differences; the Chinese self may include others (interdependent self). This study uses a self-referential effect task combined with event-related potentials (ERP), and 34 patients with MDD and 54 healthy controls (HC) were asked to judge whether an adjective was suitable for describing the self, mother, or a public person, followed by an unexpected recognition task. They were required to judge whether a word was presented during the encoding phase. The results reveal that during the encoding phase, for both self- and mother-referential adjectives, patients with MDD endorsed fewer positive adjectives and more negative adjectives than the HCs. During the recognition phase, both groups showed a typical task effect (self = mother > other), while patients recognized more self-referential adjectives than the HCs. ERP data reveal that patients with MDD show larger P2 amplitudes during the encoding stage than healthy individuals. During the recognition phase, negative adjectives evoked larger P2 amplitudes in patients than in HCs under the self-referential condition. These findings shed important light on the information processes that may contribute to our understanding of depression and may offer implications for clinical interventions.

Neural correlates of mindful emotion regulation in high and low ruminators

Depressive rumination is considered a prominent risk factor for the occurrence, severity, and duration of depressive episodes. A variety of treatment options have been developed to treat depressive rumination of which mindfulness based programs are especially promising. In the current study, we investigated the neural underpinnings of a short mindfulness intervention and mindful emotion regulation in high and low trait ruminators in an ecologically valid environment using functional near-infrared spectroscopy (fNIRS). Participants were randomly assigned to a mindfulness instruction (MT) group or an instructed thinking (IT) group. Participants in the MT group were trained to either focus their attention mindfully on their breath or their emotions, while the IT group focused their attention on the past or future. Afterwards, all participants underwent an emotion regulation paradigm in which they either watched negative or neutral movie clips. During both paradigms cortical hemodynamic changes were assessed by means of fNIRS. Participants in the MT group showed lower activity in the cognitive control network (CCN) during the focus on breath condition in comparison to the focus on emotion condition. Additionally, oxygenated hemoglobin in the MT group tended to be lower than in the IT group. Further, self-reports of emotional distress during the instruction paradigm were reduced in the MT group. During the emotion regulation paradigm, we observed reduced emotional reactivity in terms of emotional distress and avoidance in the MT group in comparison to the IT group. Furthermore, on a neural level, we observed higher CCN activity in the MT group in comparison to the IT group. We did not find any effect of rumination, neither on the intervention nor on the emotion regulation task. The results of this pilot study are discussed in light of the present literature on the neural correlates of mindfulness based interventions in rumination and emphasize the use of fNIRS to track neural changes in situ over the course of therapy.