Ilona Papousek

Trait and state positive affect and cardiovascular recovery from experimental academic stress

As compared to negative affect, only a small number of studies have examined influences of positive affect on cardiovascular stress responses, of which only a few were concerned with cardiovascular recovery. In this study, heart rate, low- and high-frequency heart rate variability, blood pressure, and levels of subjectively experienced stress were obtained in 65 students before, during and after exposure to academic stress in an ecologically valid setting. Higher trait positive affect was associated with more complete cardiovascular and subjective post-stress recovery. This effect was independent of negative affect and of affective state during anticipation of the stressor. In contrast, a more positive affective state during anticipation of the challenge was related to poor post-stress recovery. The findings suggest that a temporally stable positive affect disposition may be related to adaptive responses, whereas positive emotional states in the context of stressful events can also contribute to prolonged post-stress recovery.

Covariations of EEG asymmetries and emotional states indicate that activity at frontopolar locations is particularly affected by state factors

To test the hypothesis that activation asymmetries of the most anterior parts of the prefrontal cortex may be related to state-dependent regulation of emotion, spontaneous changes of cortical activation asymmetries from one session to a second one were related to spontaneous mood changes in two large samples (ns = 56 and 128). The interval between sessions was 2 to 4 weeks. Results show that mood changes specifically covary with changes of EEG asymmetry at the frontopolar electrode positions, but not with changes at other locations (dorsolateral frontal, temporal, and parietal). Anxiety, tension, and depression were found to decrease when frontopolar activation asymmetry shifted to the right. Taking the new findings into account may contribute to the refinement and extension of theories on EEG laterality and emotion.

Gray matter density in relation to different facets of verbal creativity.

Neuroscience studies on creativity have revealed highly variegated findings that often seem to be inconsistent. As recently argued in Fink and Benedek (Neurosci Biobehav Rev, 2012), this might be primarily due to the broad diversity in defining and measuring creativity as well as to the diversity of experimental procedures and methodologies used in this field of research. In specifically focusing on one measure of brain activation and on the well-established process of creative ideation (i.e., divergent thinking), EEG studies revealed a quite consistent and replicable pattern of right-lateralized brain activity over posterior parietal and occipital sites. In this study, we related regional gray matter density (as assessed by means of voxel-based morphometry) to different facets of psychometrically determined verbal creativity in a sample of 71 participants. Results revealed that verbal creativity was significantly and positively associated with gray matter density in clusters involving the right cuneus and the right precuneus. Enhanced gray matter density in these regions may be indicative of vivid imaginative abilities in more creative individuals. These findings complement existing functional studies on creative ideation which are, taken as a whole, among the most consistent findings in this field.

Sensitivity of EEG upper alpha activity to cognitive and affective creativity interventions

We investigated whether creative cognition can be improved by means of cognitive and affective stimulation and whether these interventions are associated with changes of EEG alpha activity. Participants were required to generate original uses of conventional objects (Alternative Uses task, AU) while the EEG was recorded. In the cognitive stimulation condition, participants worked on the AU task subsequent to the exposure to other peoples ideas. In the affective stimulation condition, they had to think creatively in positive affective states, induced via emotionally contagious sound clips. Creative cognition generally elicited alpha synchronization, most prominent in the prefrontal cortex and in the right hemisphere. The interventions were associated with stronger prefrontal alpha activity in the upper alpha band (10-12 Hz) than the control condition (no intervention), possibly indicating a state of heightened internal awareness, which might have a beneficial impact on creativity.

Quantitative assessment of five behavioural laterality measures: distributions of scores and intercorrelations among right-handers.

Five behavioural laterality measures (degree of right-handedness, ear dominance, ocular dominance, line bisection performance, and lateral preference as assessed by preferred direction of conjugate lateral eye movements) were analysed in 1171 right-handers by merging data from 15 different samples. All laterality aspects were assessed quantitatively by using well controlled performance measures instead of questionnaires. The distributions and intercorrelations of the measures as well as their test-retest reliabilities were examined. Results show moderately high reliabilities for all measures, and clearly demonstrate considerable variability among dextrals in the direction and magnitude of the obtained behavioural laterality measures. Most importantly, independence of the different measures questions some common assumptions in laterality research. It seems unlikely, for instance, that handedness and other aspects of laterality may be a product of one single underlying mechanism of brain lateralisation.

Manipulation of frontal brain asymmetry by cognitive tasks.

The purpose of the present study was to evaluate whether verbal fluency tasks may specifically induce relatively greater left than right hemispheric activation in the dorsolateral prefrontal cortex. The effectiveness of the manipulation was evaluated by EEG, which was recorded during performance of the verbal fluency task and during two control conditions, i.e., a baseline condition without cognitive demands, and a mental arithmetic task, respectively. The results demonstrate that the desired effect can only be achieved in individuals with good performance on the verbal fluency task. Good and poor performers do not only differ in lateral asymmetry, but also in the most affected region within the prefrontal cortex. Whereas good performers show relatively increased activation in the cortical region and hemisphere putatively most specialized for this kind of task (i.e., the left dorsolateral frontal cortex), poor performers show a marked shift of frontopolar asymmetry to the right.

Dissociated autonomic regulation during stress and physical complaints

OBJECTIVE In order to evaluate the relevance of individual differences in the regulation of autonomic subsystems to psychosomatic processes, reactivity of the autonomic nervous system to an emotional stressor was related to the occurrence of physical complaints. In contrast to most other studies, the measures were related to the degree of actually experienced stress. METHODS In a large sample (n=111), electrodermal activity (EDA) and heart rate variability (HRV) were obtained at rest and during emotional stress. Physical complaints were assessed by a standardized symptom checklist providing subscales for different physiological systems. RESULTS Subjects who were actually stressed by the stress induction procedure but showed only weak reactivity of EDA, and subjects who were only slightly stressed but showed a marked EDA response reported a high amount of gastrointestinal complaints. A greater decrease of high-frequency HRV from the rest to the stress condition was associated with reports of relatively more cardiovascular complaints. CONCLUSION Findings indicate that the link between regulation of EDA and gastrointestinal functions has to be localized in higher brain structures and support the hypothesis that minor autonomic dysregulation may represent one pathway linking negative affect and the development of physical disorders.

Associations between EEG asymmetries and electrodermal lability in low vs. high depressive and anxious normal individuals.

In order to investigate one aspect of cortical-autonomic control, cortical activation asymmetries, measured by EEG, were related to activity of the sympathetic nervous system, measured by EDA (electrodermal lability, number of spontaneous fluctuations), in two large samples. Since it may help to explain the participation of psychological factors in the development of various somatic complaints and disorders, we examined whether inter-individual differences in autonomic nervous system regulation may exist that are related to stress/anxiety and depression within the normal range. Results demonstrate substantial modifications of functional hemisphere asymmetries in the modulation of EDA by these emotional factors and suggest that activation asymmetries in orbital and dorsolateral frontal regions reflect two different cortical sub-systems regulating electrodermal activity. The findings may, to some extent, provide an explanation for contradictory results in previous studies and may encourage research in psychosomatics and other clinical fields (e.g. schizophrenia).

Frontal brain asymmetry and affective flexibility in an emotional contagion paradigm

This study was aimed at examining the relation of an individuals EEG asymmetry in the lateral frontal cortex, assessed in resting conditions, to affective flexibility. An auditory paradigm was used to induce negative (sad) and positive (cheerful) affective states, and state-dependent shifts of dorsolateral EEG asymmetry in response to and after the emotional provocations were observed. A Left>Right activation pattern at rest was associated with a shift to the right during negative and a shift to the left during positive stimulation, and efficient recovery after negative stimulation. Right>Left participants appeared unresponsive to both sounds. Distinct and differentiated responses to provocation with negative and positive affect and efficient recovery suggest that Left>Right prefrontal activity at rest is related to a flexible pattern of affective responding, which has been linked to adaptive emotional processing in the relevant literature.

The time-course of EEG alpha power changes in creative ideation.

Increases in EEG alpha power during creative ideation are among the most consistent findings in the neuroscientific study of creativity, but existing studies did not focus on time-related changes of EEG alpha activity patterns during the process of creative ideation so far. Since several cognitive processes are involved in the generation of creative ideas, different EEG correlates may result as a function of time. In this study we addressed this crucial point. Forty-five participants worked on the “Alternative Uses Task” while the EEG was recorded and changes in task-related power (relative to rest) in the upper-frequency band (10–12 Hz) for three isochronous time intervals of the idea generation period were determined. Alpha power changes during idea generation followed a characteristic time course: we found a general increase of alpha power at the beginning of idea generation that was followed by a decrease and finally by a re-increase of alpha prior to responding that was most pronounced at parietal and temporal sites of the right hemisphere. Additionally, the production of more original ideas was accompanied by increasing hemispheric asymmetry (more alpha in the right than left hemisphere) with increasing duration of the idea generation period. The observed time course of brain activity may reflect the progression of different but well-known stages in the idea generation process: that is the initial retrieval of common and old ideas followed by the actual generation of novel and more creative ideas by overcoming typical responses through processes of mental simulation and imagination.