Verena Leutgeb

An event-related potential study on exposure therapy for patients suffering from spider phobia

The present event-related potential (ERP) study investigated electrocortical changes related to cognitive behavior therapy (CBT) in spider phobic females. Forty-five patients and twenty non-phobic women were presented with phobia-relevant, generally fear-inducing, disgust-inducing and affectively neutral pictures in a first EEG session. Phobic patients were randomly assigned to either a therapy (TG) or a waiting-list (WG) group. EEG measurement was repeated after CBT or a waiting period. ERPs were extracted in the time windows 340-500ms (P300), 550-770ms (late positive potential (LPP), early LPP) and 800-1500ms (late LPP). Relative to controls, untreated phobics showed enhanced amplitudes of P300 and early LPP in response to spider pictures. This most likely reflects the emotional significance of the phobic stimulus, which automatically draws attention. The therapy effect consisted of a significant enhancement of late LPP amplitudes in response to spider pictures. Results are discussed in terms of reduced attentional avoidance.

Source localization of late electrocortical positivity during symptom provocation in spider phobia: an sLORETA study.

This symptom provocation study on spider phobia investigated sources of late event-related potentials (ERPs) using sLORETA (standardized low resolution brain electromagnetic tomography). Twenty-five phobic female patients and 20 non-phobic controls were confronted with phobia-relevant, generally fear-inducing, disgust-inducing and affectively neutral pictures while an electroencephalogram was recorded. Mean amplitudes of ERPs were extracted in the time windows 340–500 ms (P300) and 550–770 ms (late positive potential, LPP). Phobics showed enhanced P300 and LPP amplitudes in response to spider pictures relative to controls. Sources were mainly located in areas engaged in visuo-attentional processing (occipital and parietal regions, ventral visual pathway). Moreover, there were sources in areas which are crucial for emotional processing and the representations of aversive bodily states (cingulate cortex, insula). Further sources were located in premotor areas reflecting the priming of flight behaviour. Our findings are in good accordance with existing brain imaging studies and underline that source localization is a useful alternative for identifying phobia-relevant cortical regions.

Psychophysiology of spider phobia in 8- to 12-year-old girls

The present investigation focused on late event-related potentials (ERPs) and facial electromyographic (EMG) activity in response to symptom provocation in 8- to 12-year-old spider phobic girls and compared results to those in non-fearful controls. Fourteen patients and 14 controls were presented with phobia-relevant, generally fear-inducing, disgust-inducing and affectively neutral pictures in an EEG/EMG session. ERPs were extracted in the time-windows 340-500ms (P300) and 550-770ms (late positive potential, LPP). Relative to controls, phobics showed enhanced amplitudes of P300 and LPP in response to spider pictures. This result is interpreted to reflect motivated attention to emotionally salient stimuli. Moreover, phobics showed enhanced average facial EMG activity of the levator labii and the corrugator supercilii in response to spider pictures, reflecting the negative valence and disgust relevance of spiders. Additionally, spider phobic girls relative to controls showed higher overall disgust proneness and heightened average facial EMG activity in both muscle regions in response to disgust stimuli, possibly revealing a disgust-based origin of spider phobia in children. These aspects should be considered in psychotherapeutic treatment of childhood spider phobia.

Exposure therapy leads to enhanced late frontal positivity in 8- to 13-year-old spider phobic girls

Highlights ► Spider phobic girls show enhanced late positivity after psychotherapy. ► Reduced overall disgust proneness after psychotherapy. ► Spider phobia should already be treated in childhood.

Propensity and sensitivity measures of fear and disgust are differentially related to emotion-specific brain activation

Neuroimaging studies on individual differences in experiencing disgust and fear have indicated that disgust propensity and trait anxiety are able to moderate brain activity. The moderating role of disgust sensitivity and anxiety sensitivity has not been investigated thus far. Both sensitivity traits refer to the tendency of a person to perceive harmful consequences of experiencing fear and disgust. Eighteen female subjects viewed and subsequently rated pictures for the elicitation of disgust, fear and a neutral affective state. The viewing of the aversive pictures was associated with activation of visual processing areas, the amygdala, the insula and the orbitofrontal cortex (OFC). In the disgust condition, disgust propensity was positively correlated with activation of attention-related areas (parietal cortex, anterior cingulate cortex (ACC)) and brain regions involved in valence and arousal processing (OFC, insula). For the fear condition, we observed positive correlations between trait anxiety and activation of the ACC, the insula, and the OFC. Correlations between brain activity and sensitivity measures were exclusively negative and concerned areas crucial for emotion regulation, such as the medial and dorsolateral prefrontal cortex (MPFC, DLPFC). Thus, individuals high in disgust/anxiety sensitivity might have difficulties to successfully control the specific affective experience.

Disrupted response inhibition toward facial anger cues in children with attention-deficit hyperactivity disorder (ADHD): an event-related potential study.

This event-related potential study focused on neural correlates of inhibitory affective control in attention-deficit hyperactivity disorder (ADHD). Sixteen boys with ADHD and 16 healthy boys underwent an emotional Go/NoGo task with pictures of facial expressions from the categories anger, sadness, happiness, and neutral. The participants were instructed to execute or withhold a motor response to specific emotions. Patients relative to controls displayed a severe impairment in response inhibition toward anger cues, which was accompanied by a reduced P300 amplitude (positive voltage deflection about 300 ms after picture onset). The control group showed a P300 differentiation of the affective categories that was absent in the ADHD group. The pronounced anger-processing deficit in ADHD patients might be linked to their interpersonal difficulties and should be addressed in psychotherapy.

Frontal late positivity in dental phobia: A study on gender differences

Although dental phobia afflicts men and women, gender differences in neural correlates of this disorder have not been investigated thus far. We recorded event-related potential (ERPs) in 30 individuals with dental phobia (15 women, 15 men with comparable disorder severity) and 30 nonphobic controls (15 women, 15 men) while they passively viewed pictures depicting dental treatment, generally fear-eliciting, disgust-eliciting and neutral contents. Male and female individuals with dental phobia as compared with controls displayed an enlarged centro-parietal late positivity (300-1500 ms). Gender difference concerned prefrontal ERPs. Only men with dentophobia showed an enhanced positivity towards the phobic relative to the neutral pictures in the time window between 300 and 1500 ms. Such a differentiation was absent in the other groups (male controls, female phobics, female controls). This finding indicates a gender-dependent recruitment of frontal attention networks in dental phobia and might reflect that male and female sufferers of dentophobia differ with regard to controlled attention focusing and cognitive avoidance during exposure.

Sex differences in the functional and structural neuroanatomy of dental phobia

Although dental phobia is a common mental disorder, which afflicts both men and women, little is known about sex differences at the neural level. Patients suffering from dental phobia (20 men, 25 women) and healthy controls (18 men, 23 women) participated in a functional magnetic resonance imaging (fMRI) experiment. They were shown pictures depicting dental treatment, generally fear-eliciting, disgust-eliciting and neutral contents. After the fMRI experiment, the participants rated the affective value of the pictures. Additionally, grey matter volume (GMV) was compared between patients and controls, as well as between the sexes. Male and female patients responded differently to the phobogenic pictures. Women showed greater activation of the caudate nucleus, whereas men exhibited enhanced dorsolateral prefrontal cortex (DLPFC) involvement. Their DLPFC activation was negatively correlated with experienced arousal. Dentophobic females were characterized by a greater caudate volume relative to phobic males. The GMV of this structure was positively correlated with experienced arousal during exposure and symptom severity, only in female patients. This study provides first evidence of sex-specific brain activation and structure in patients suffering from dental phobia. The neural pattern during symptom provocation as well as the brain structural specificity might mirror different attention and self-control strategies of both sexes. The consideration of such differences could contribute to greater effectiveness in treating dental phobia.

Naphthoquinones and Anthraquinones from Scent Glands of a Dyspnoid Harvestman, Paranemastoma quadripunctatum

Extracts of Paranemastoma quadripunctatum (Opiliones, Dyspnoi, Nemastomatidae) contained seven components, all of which likely originated from the secretion of well-developed prosomal scent glands. The two main components (together accounting for more than 90% of the secretion) were identified as 1,4-naphthoquinone and 6-methyl-1,4-naphthoquinone. The minor components were 1,4-naphthalenediol, two methoxy-naphthoquinones (2-methoxy-1,4-naphthoquinone, and 2-methoxy-6-methyl-1,4-naphthoquinone) and two anthraquinones (2-methyl-9,10-anthraquinone and a dimethyl-9,10-anthraquinone). While some chemical data on scent gland secretions of the other suborders of Opiliones (Cyphophthalmi, palpatorean Eupnoi, and Laniatores) already exist, this is the first report on the scent gland chemistry in the Dyspnoi. Naphthoquinones are known scent gland exudates of Cyphophthalmi and certain Eupnoi, methoxy-naphthoquinones and anthraquinones are new for opilionid scent gland secretions.

Affective perception and imagery: A NIRS study.

The activation of cortical attention networks during affective picture processing has been extensively studied, whereas little is known about affective imagery. It is still unclear whether differences in emotional stimulus content are able to modulate visual cortex activation during imagery. Moreover, individual differences in emotional reactivity and imagery ability have not been investigated. The aim of this experiment was to examine these processes by means of near-infrared spectroscopy (NIRS). Thirty-five healthy adults were instructed to look at affective (disgust and happy) and neutral pictures and afterwards visualize them during multi-channel NIRS recording. Our main results indicated a differential involvement of parietal and occipital areas in the perception and imagery of affective pictures. In general, picture perception provoked increased oxygenated hemoglobin in occipital regions, whereas imagery was associated with an increase in parietal areas. Emotional content modulated activation of the left occipital cortex during both picture perception and imagery. Affective pictures (disgust and happy) provoked greater activation compared to neutral ones. Additionally, the self-rated imagery ability of the participants was positively correlated with their occipital activation during affective imagery. Thus, occipital activation might be crucial for the quality of imagery. In contrast, all correlations with emotional traits (e.g. trait disgust) and oxygenation were nonsignificant, which might be due to the fact that those personality factors predominantly modulate the activation of subcortical limbic structures which are not accessible with NIRS.