Biomedical subjects

Andreas Mühlberger

Publications and source records attributed to Andreas Mühlberger.

8 recordsLinked to original sources

PubMed2006

Additive effects of serotonin transporter and tryptophan hydroxylase-2 gene variation on emotional processing.

Prior studies reported that functional variants of both the serotonin transporter (5-HTT) and tryptophan hydroxylase-2 genes (TPH2), 2 key regulators of the serotonergic signaling pathway, modulate amygdala activation during emotional processing. We addressed the question whether these 2 gene variants modulate each other, using an emotional picture-processing task. Specifically, we measured event-related potentials (ERPs) during a passive emotional picture perception task, focusing on ERPs for the early posterior negativity (EPN) around 240 ms and for the slow wave starting at 315 ms. We found evidence for increased neural activity at 240 ms in individuals who carried 1 or 2 copies of the low-expression short variant of the 5-HTT. Carriers of T variant of the TPH2 also showed a tendency toward increased neural activity at 240 ms. Moreover, we observed an additive effect of both genotypes for EPN, with highest neural activity to emotional stimuli in individuals carrying combination of both short variant of 5-HTT and T variant of TPH2. Our results indicate that both the 5-HTT and the TPH2 genotypes modulate the sensory encoding of affective stimuli during early steps of visual processing and reveal additive effects of 2 genes in the serotonergic control of emotion regulation.

Adult↗

PubMed2006

Is emotion processing affected by advancing age? An event-related brain potential study.

The recognition of emotions is presumably affected by advancing age, which is known from subjective reports and recognition tasks. To differentiate perception from executive function more clearly, the discrimination of emotions was investigated with event-related brain potentials (ERPs) from 21 electrodes in 14 elderly (ages 59-74) and 13 younger participants (ages 30-40) triggered by a rapid (3 Hz) serial visual presentation (RSVP) of high and low arousing pictures. Additionally, affective ratings of valence and arousal of a representative sample of 54 pictures were obtained. An early posterior negativity (EPN) as an index of early emotion discrimination was analyzed in an early (168-232 ms) and a late (232-296 ms) time window. Both groups showed an EPN associated with pictures of high emotional arousal. However, the EPN was slightly delayed in elderly participants. Thus, the affective modulation of the EPN was reduced in elderly subjects in the early time window, but not in the late time window. Ratings of valence or arousal did not differ between groups. In sum, these results point towards an age-related delay of early visual emotion discrimination. However, this delay seems not to influence further evaluative processing of emotional stimuli.

Adult↗

PubMed2006

Phylo- and ontogenetic fears and the expectation of danger: differences between spider- and flight-phobic subjects in cognitive and physiological responses to disorder-specific stimuli.

To compare specific phobias with an assumed phylogenetic or ontogenetic origin in responses to fear-relevant (FR) stimuli, 17 spider- and 17 flight-phobic participants were exposed to pictures of spiders, flight accidents, or mushrooms randomly followed by either a startling noise or nothing else. While both groups showed a disorder-specific expectancy bias, only spider-phobic participants exhibited a disorder-specific covariation bias. Spider-phobic participants also showed enhanced skin conductance responses (SCRs), event-related brain potentials (ERPs), and startle responses triggered by disorder-specific FR pictures while flight-phobic participants showed only disorder-specific enhanced SCRs. In sum, our direct comparison between ontogenetic and phylogenetic phobias revealed that the former is characterized by biased and enhanced responses triggered by disorder-specific FR stimuli presumably based on a biological preparedness.

Adult↗

PubMed2006

Electromyographic responses to static and dynamic avatar emotional facial expressions.

Facial muscular reactions to avatars' static (neutral, happy, angry) and dynamic (morphs developing from neutral to happy or angry) facial expressions, presented for 1 s each, were investigated in 48 participants. Dynamic expressions led to better recognition rates and higher intensity and realism ratings. Angry expressions were rated as more intense than happy expressions. EMG recordings indicated emotion-specific reactions to happy avatars as reflected in increased M. zygomaticus major and decreased M. corrugator supercilii tension, with stronger reactions to dynamic as compared to static expressions. Although rated as more intense, angry expressions elicited no significant M. corrugator supercilii activation. We conclude that facial reactions to angry and to happy facial expressions hold different functions in social interactions. Further research should vary dynamics in different ways and also include additional emotional expressions.

Adult↗

PubMed2005

Emotion processing in Parkinson's disease: dissociation between early neuronal processing and explicit ratings.

OBJECTIVE: Patients suffering from Parkinson's disease (PD) have a diminished ability to discriminate facial expressions of emotion. We investigated early emotion discrimination deficits in PD by means of event-related potentials (ERPs). METHODS: Emotional pictures were presented to 14 PD patients and 14 healthy controls in a rapid serial visual presentation paradigm (three frames per second) while EEG was recorded. In addition, valence and arousal ratings were obtained for a representative subsample of 54 pictures. RESULTS: PD patients rated pictures of highly arousing content as less exciting than did healthy controls. Pictures of high compared to low emotional arousal were associated with a pronounced relative negative shift in the ERP waveform over parietal and occipital sites developing about 220 ms after picture onset. This early posterior negativity (EPN) did not differ between PD and control group. CONCLUSIONS: This dissociation of affective ratings and early ERP components supports the view that PD is associated with blunted emotional responses, but there is no evidence for a deteriorated early visual processing of emotional stimuli. SIGNIFICANCE: Frequently reported deficits in emotion discrimination are likely not due to deficits in early emotion processing.

Aged↗

PubMed2005

Electrocortical evidence for an early abnormal processing of panic-related words in panic disorder patients.

Panic patients are hypothesized to have particularly elaborated cortical networks for panic-related stimuli, and this characteristic should be associated with an abnormal automatic processing of these stimuli. Panic-related and neutral words were presented to 25 panic patients and 25 matched healthy controls either at individually determined perception thresholds (threshold condition) or for 1000 ms (above threshold condition). Word recognition for words presented at perception threshold (threshold words), and event-related brain potentials (ERPs) triggered by threshold and above threshold words were analyzed. In the threshold condition, both panic patients and control participants correctly recognized more panic-related than neutral words. An additional analysis restricted to participants who used an intuitive strategy for word identification revealed an enhanced frequency of correctly identified panic-related words in panic patients. In the ERPs, only panic patients exhibited enhanced positive potentials during early time windows (200-400 ms after stimulus presentation) triggered by panic-related compared to neutral threshold words. In late (400-600 ms) and very late (600-1000 ms) time windows, both groups showed a greater ERP positivity for panic-related than for neutral words. These data suggest that panic patients are characterized by an early automatic and elaborated processing of disorder-relevant stimuli.

Adult↗

PubMed2005

Binocular rivalry between emotional and neutral stimuli: a validation using fear conditioning and EEG.

When two incompatible pictures are projected to the two eyes, they compete for perceptual dominance. Previous research has claimed that meaningful and emotionally valenced pictures predominate over neutral pictures in this rivalry. This may be interpreted as evidence for preferential processing of emotionally significant stimuli in the visual system but it is difficult to dismiss that the physical characteristics of the different pictures or response biases influenced the results of these studies. Thus, we set out to examine the influence of emotion using methods eliminating the influence of physical characteristics and minimizing response biases. We used simple visual patterns and induced emotional valence by fear conditioning. In Experiment 1 the aversive CS+ predominated over the CS-. In Experiment 2 we extended previous findings by showing that participants' self-reported perception is validated by corresponding steady-state visually evoked potentials in the EEG in the context of such a conditioning experiment. This was accomplished by frequency coding the rivalling stimuli with a stimulus specific pattern reversal and extracting the corresponding frequency from the occipital lobe EEG. Taken together, these studies provide further evidence that picture valence can influence perception in binocular rivalry. This is discussed in terms of subcortical mechanisms supporting the efficient processing of threatening information.

Adult↗

PubMed2004

Modulation of event-related brain potentials during affective picture processing: a complement to startle reflex and skin conductance response?

The present study compared startle response, skin conductance response (SCR) and subjective variables (valence and arousal ratings, viewing time) assessed in an affective picture paradigm with simultaneously registered event-related brain potentials (ERPs) parameters such as P300 and positive slow waves (PSW). Pleasant, neutral and unpleasant pictures from the International Affective Picture System [Lang, P.J., Bradley, M.M., Cuthbert, B.N., 1999. International Affective Picture System (IAPS): Instruction manual and affective ratings. Technical Report A-4, Center for Research in Psychophysiology. University of Florida, Gainesville, Florida] were presented for 8 s, and startle probes were delivered during picture presentation. Startle response was modulated by picture valence, and SCR by picture arousal. ERP positivity was greater for pleasant and unpleasant than for neutral pictures for the P300 amplitude and the positive slow wave (PSW). ERPs showed characteristic differences and a distinct time course for pictures of different valence categories and may deliver useful information not contained in startle response or SCR measures. The simultaneous registration of startle responses and ERPs in the affective picture paradigm seems valuable.

Adult↗