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DOES AGE INFLUENCE BRAIN POTENTIALS DURING AFFECTIVE PICTURE PROCESSING IN MIDDLE-AGED WOMEN?
(2017)
Recent research indicates that non- invasive stimulation of the afferent auricular vagal nerve (tVNS) may modulate various cognitive and affec-tive functions, likely via activation of the locus coeruleus- norepinephrine (LC- NE) system. In a series of ERP studies we found that the attention- related P300 component is enhanced during continuous vagal stimula-tion, compared to sham, which is also related to increased salivary alpha amylase levels (a putative indirect marker for central NE activation). In another study, we investigated the effect of continuous tVNS on the late positive potential (LPP), an electrophysiological index for motivated atten-tion toward emotionally evocative cues, and the effects of tVNS on later recognition memory (1- week delay). Here, vagal stimulation prompted earlier LPP differences (300- 500 ms) between unpleasant and neutral scenes. During retrieval, vagal stimulation significantly improved memory performance for unpleasant, but not neutral pictures, compared to sham stimulation, which was also related to enhanced salivary alpha amylase levels. In line, unpleasant images encoded under tVNS compared to sham stimulation also produced enhanced ERP old/new differences (500- 800 ms) during retrieval indicating better recollection. Taken together, our studies suggest that tVNS facilitates attention, learning and episodic memory, likely via afferent projections to the arousal- modulated LC- NE system. We will, however, also show data that point to critical stimulation parameters (likely duration and frequency) that need to be considered when applying tVNS
THE P300 AND THE LC-NE SYSTEM: NEW INSIGHTS FROM TRANSCUTANEOUS VAGUS NERVE STIMULATION (TVNS)
(2017)
Bottom-up saliency is often cited as a factor driving the choice of fixation locations of human observers, based on the (partial) success of saliency models to predict fixation densities in free viewing. However, these observations are only weak evidence for a causal role of bottom-up saliency in natural viewing behaviour. To test bottom-up saliency more directly, we analyse the performance of a number of saliency models---including our own saliency model based on our recently published model of early visual processing (Schütt & Wichmann, 2017, JoV)---as well as the theoretical limits for predictions over time. On free viewing data our model performs better than classical bottom-up saliency models, but worse than the current deep learning based saliency models incorporating higher-level information like knowledge about objects. However, on search data all saliency models perform worse than the optimal image independent prediction. We observe that the fixation density in free viewing is not stationary over time, but changes over the course of a trial. It starts with a pronounced central fixation bias on the first chosen fixation, which is nonetheless influenced by image content. Starting with the 2nd to 3rd fixation, the fixation density is already well predicted by later densities, but more concentrated. From there the fixation distribution broadens until it reaches a stationary distribution around the 10th fixation. Taken together these observations argue against bottom-up saliency as a mechanistic explanation for eye movement control after the initial orienting reaction in the first one to two saccades, although we confirm the predictive value of early visual representations for fixation locations. The fixation distribution is, first, not well described by any stationary density, second, is predicted better when including object information and, third, is badly predicted by any saliency model in a search task.
How distinct implicit and explicit motive systems differ has long been unclear. Schultheiss' (2001) information processing account of implicit motive arousal hypothesized that implicit motives respond to nonverbal stimuli to influence non-declarative measures of motivation and that explicit motives respond to verbal stimuli to influence declarative measures of motivation. Moreover, in individuals high in referential competence, i.e., with the ability to quickly translate non-verbal stimuli into a verbal representation, implicit motives are thought to respond to verbal stimuli and influence declarative measures of motivation and explicit motives are thought to respond to nonverbal stimuli and to influence non-declarative measures of motivation. The present study tested these hypotheses by assessing liking ratings as a declarative response format and an affective stroop task as a non-declarative response format using emotion words as verbal and emotional facial expressions as non-verbal stimuli. Individual power, affiliation, and achievement motive dispositions were assessed via the Picture Story Excercise for implicit motives and via questionnaires for explicit motives. Referential competence was assessed via a colour-naming/-reading task. I found that as expected explicit and implicit motives overall were not correlated across subjects. Moreover, implicit and explicit motives affected declarative and non-declarative responses for verbal and non-verbal stimuli. As predicted, however, implicit motives responded to verbal stimuli and influenced declarative responses more strongly for individuals high compared to those low in referential competence. Likewise, explicit motive effects were moderated by referential competence in some - but not all - of the predicted conditions. These results show that implicit and explicit motives can influence declarative and non-declarative responses to verbal and non-verbal stimuli. They support the hypothesis that referential processing is needed for implicit motives to respond to verbal stimuli and influence declarative response formats, and they partly support the hypothesis that referential processing plays a role for the influence of explicit motives. Results for explicit motives may suggest that new measures are needed to assess the referential competence to translate verbal stimuli into non-verbal representations. Overall, the findings provide support to the information processing account of implicit motive arousal by Schultheiss' (2001), suggesting that a non-verbal and non-declarative implicit motive system and a distinct verbal and declarative explicit motive system interact via referential processing, i.e., by translating information between representational formats.
This study examined the relationships between the three phenotypic domains of the triarchic model of psychopathy —boldness, meanness, disinhibition— and electrophysiological indices of inhibitory control (NoGo-N2/NoGo-P3). EEG data from a 256-channel dense array were recorded while participants (135 un-dergraduates assessed via the Triarchic Psychopathy Measure) performed a Go/NoGo task with three types of stimuli (60% frequent-Go, 20% infrequent-Go, 20% infrequent-NoGo). N2 was defined as the mean amplitude between 240 ms and 340 ms after stimuli onset over fronto-central sensors on correct trials; P300 was defined as the mean amplitude between 350 ms and 550 ms after stimuli onset over centro-parietal sensors on correct trials. Multiple regression analyses using gender-corrected triarchic scores as predictors revealed that only Disinhibition scores significantly predicted reduced NoGo-N2 amplitudes (3.5% explained variance, beta weight = .23, p < .05) and reduced P3 amplitudes for NoGo and infrequent-Go trials (3.1 and 3.2% explained variance, respectively, beta weights = -.21, ps < .05). Our results indicate that high disinhibition entails deviations in early conflict monitoring processes (reduced NoGo-N2), as well as in latter evaluative and updating processing stages of infrequent events (reduced NoGo-P3 and infrequent-Go-P3). The null contribution of meanness and boldness domains in these results suggests that N2 and P3 amplitudes in Go/NoGo tasks could be considered as neurobiological indices of the externalizing tendencies comprised in this personality disorder.
Background and Aims: Ostarek et al. (2019) claimed a conclusive
demonstration that language comprehension relies profoundly on
visual simulations. They presented participants with visual noise during sentence-picture verification (SPV) and measured lateralized button response speed. The authors selectively eliminated the classical congruency effect (faster yes decisions when pictures match the objects implied by the sentences) with ‘‘high level’’ noise made from images of other objects. However, that visual noise included tool pictures, known to activate lateralized motor affordances. Moreover, some of their sentences described motor actions. This raises the question whether motor simulation may have contaminated their results.
Methods: Replicating Ostarek et al. (2019), 33 right-handed
participants performed SPV but either without visual noise or while viewing (a) only left-handled or (b) only right-handled or (c) alternatingly left- and right-handled tools. Accuracy and reaction times of manual yes responses were analyzed. Additionally, hand-relatedness of sentences was rated.
Results: Replicating Ostarek et al. (2019), the classical SPV congruency effect appeared without noise and vanished when alternatingly handled tools were presented. Crucially, it reappeared when noise objects were consistently either left- or righthandled. Higher hand-relatedness of sentence content reduced SPV performance and accuracy was lower with right-handled noise.
Conclusion: First, we demonstrated an interaction between motor-
related language, visual affordances and motor responses in SPV.
This result supports the embodied view of language processing.
Second, we identified a motor process not previously known in SPV. This extends our understanding of mental simulation and calls for methodological controls in future studies.