Attention and personality in augmenting/reducing of visual evoked potentials

Earlier research has shown that extraverts tend to increase their visual evoked potential amplitudes with increasing light intensity (augmenting), while introverts reach their maximum amplitude at lower intensities (reducing). The evoked response has normally been measured from association areas of the brain (at the vertex). The present study measured VEP amplitudes over visual cortex and at the vertex, using four light intensities in two conditions, where attention was either directed towards the light stimuli, or away from them by a concurrent auditory task. Forty subjects were classified as extraverts or introverts based on the Eysenck Personality Inventory. The results show that attention interacted significantly with extraversion. Introverts exhibited a narrower focus of attention, while higher amplitudes and amplitude-intensity functions when attending to the light flashes and lower when distracted. Extraverts showed smaller differences between conditions, indicating a more evenly distributed attention. Higher arousal in introverts is the probable cause of their narrower focus of attention. There were marked differences in the distribution of activity between vertex and occipital cortex. Introverts showed relatively stronger occipital responses and extraverts stronger vertex responses across all intensities and in both conditions. The predisposition for mainly perceptual responses to aversive stimuli in introverts, and for general alerting and motor preparatory responses in extraverts, are interpreted as supportive of Brebner and Cooper's hypothesis that introverts are ‘geared to inspect’ and extraverts are ‘geared to respond’.     

Misalignment Between Research Hypotheses and Statistical Hypotheses: A Threat to Evidence-Based Medicine?

Topoi - Evidence-based medicine frequently uses statistical hypothesis testing. In this paradigm, data can only disconfirm a research hypothesis’ competitors: One tests the negation...     

Cortical midline structures and the self

For a long time philosophers and psychologists have been intrigued by the question of the self. More recently, this has become a topic of discussion in neuroscience. In this article, we suggest that the processing of self-referential stimuli in cortical midline structures (CMS) is a fundamental component in generating a model of the self. Drawing from neuroimaging studies, we distinguish between representation, monitoring, evaluation and integration of self-referential stimuli. All of these subfunctions are related to distinct regions within the CMS. This relationship between self-referential processing and CMS might provide novel insight into the neural correlates underlying the constitution of the self.     

Three turtles in danger: spontaneous construction of causally relevant spatial situation models

In 4 experiments, the author explored the spontaneous construction of spatial situation models during discourse comprehension by using the sentence-recognition paradigm of J. D. Bransford, J. R. Barclay, and J. J. Franks (1972). In Experiment 1, signaling causal relevance of spatial relations was a necessary precondition for replicating their original finding of spontaneously constructed spatial representations. Causal relevance was ensured in the subsequent experiments by a judgment task indirectly demanding the evaluation of described spatial relations with regard to causal relevance. Participants spontaneously constructed spatial situation models of text presented auditorily or visually. Effects of spontaneous construction were more reliable when encoding was easier. The results suggest a revised interpretation of J. D. Bransford et al.'s study and corroborate recent evidence showing that relevant spatial information in texts is reliably represented.     

Emotional avoidance: an experimental test of individual differences and response suppression using biological challenge

The present study examined the affective consequences of response inhibition during a state of anxiety-related physical stress. Forty-eight non-clinical participants were selected on the basis of pre-experimental differences in emotional avoidance (high versus low) and subjected to four inhalations of 20% carbon dioxide-enriched air. Half of the participants were instructed to inhibit the challenge-induced aversive emotional state, whereas the other half was instructed to simply observe their emotional response. Participants high in emotional avoidance compared to those low in emotional avoidance responded with greater levels of anxiety and affective distress but not physiological arousal. Individuals high in emotional avoidance also reported greater levels of anxiety relative to the low emotional avoidance group when suppressing compared to observing bodily sensations. These findings are discussed in terms of the significance of emotional avoidance processes during physical stress, with implications for better understanding the nature of panic disorder.