251 research outputs found
Influences of reward in the relevant dimension on conflict processing.
No full text<p>(<b>A</b>) Averaged ERP distribution maps of the difference between incongruent and congruent trials (<i>Wi0-Wc</i>) in no-reward trials reveal the incongruency-related negativity (N<sub>inc</sub>) over centro-parietal sites followed by the late positivity component (LPC) over parietal sites. (<b>B</b>) The analogous comparison in potential-reward trials revealed that the N<sub>inc</sub> and LPC components were replaced by earlier modulations in the centro-parietal and parietal ROIs. Gray-shaded areas indicate significant mean-amplitude differences in the respective ROIs (p-values<.05). (<b>C</b>) ERP waveforms for each condition as well as the respective ERP difference waves are shown for selected ROIs (averaged across channels).</p
Reward associations reduce behavioral interference by changing the temporal dynamics of conflict processing.
No full textAssociating stimuli with the prospect of reward typically facilitates responses to those stimuli due to an enhancement of attentional and cognitive-control processes. Such reward-induced facilitation might be especially helpful when cognitive-control mechanisms are challenged, as when one must overcome interference from irrelevant inputs. Here, we investigated the neural dynamics of reward effects in a color-naming Stroop task by employing event-related potentials (ERPs). We found that behavioral facilitation in potential-reward trials, as compared to no-reward trials, was paralleled by early ERP modulations likely indexing increased attention to the reward-predictive stimulus. Moreover, reward changed the temporal dynamics of conflict-related ERP components, which may be a consequence of an early access to the various stimulus features and their relationships. Finally, although word meanings referring to potential-reward colors were always task-irrelevant, they caused greater interference compared to words referring to no-reward colors, an effect that was accompanied by a relatively early fronto-central ERP modulation. This latter observation suggests that task-irrelevant reward information can undermine goal-directed behavior at an early processing stage, presumably reflecting priming of a goal-incompatible response. Yet, these detrimental effects of incongruent reward-related words were absent in potential-reward trials, apparently due to the prioritized processing of task-relevant reward information. Taken together, the present data demonstrate that reward associations can influence conflict processing by changing the temporal dynamics of stimulus processing and subsequent cognitive-control mechanisms
Using bacterial biomarkers to identify early indicators of cystic fibrosis pulmonary exacerbation onset
No full textAcute periods of pulmonary exacerbation are the single most important cause of morbidity in cystic fibrosis patients, and may be associated with a loss of lung function. Intervening prior to the onset of a substantially increased inflammatory response may limit the associated damage to the airways. While a number of biomarker assays based on inflammatory markers have been developed, providing useful and important measures of disease during these periods, such factors are typically only elevated once the process of exacerbation has been initiated. Identifying biomarkers that can predict the onset of pulmonary exacerbation at an early stage would provide an opportunity to intervene before the establishment of a substantial immune response, with major implications for the advancement of cystic fibrosis care. The precise triggers of pulmonary exacerbation remain to be determined; however, the majority of models relate to the activity of microbes present in the patient's lower airways of cystic fibrosis. Advances in diagnostic microbiology now allow for the examination of these complex systems at a level likely to identify factors on which biomarker assays can be based. In this article, we discuss key considerations in the design and testing of assays that could predict pulmonary exacerbations
The role of stimulus salience and attentional capture across the neural hierarchy in a stop-signal task.
No full textInhibitory motor control is a core function of cognitive control. Evidence from diverse experimental approaches has linked this function to a mostly right-lateralized network of cortical and subcortical areas, wherein a signal from the frontal cortex to the basal ganglia is believed to trigger motor-response cancellation. Recently, however, it has been recognized that in the context of typical motor-control paradigms those processes related to actual response inhibition and those related to the attentional processing of the relevant stimuli are highly interrelated and thus difficult to distinguish. Here, we used fMRI and a modified Stop-signal task to specifically examine the role of perceptual and attentional processes triggered by the different stimuli in such tasks, thus seeking to further distinguish other cognitive processes that may precede or otherwise accompany the implementation of response inhibition. In order to establish which brain areas respond to sensory stimulation differences by rare Stop-stimuli, as well as to the associated attentional capture that these may trigger irrespective of their task-relevance, we compared brain activity evoked by Stop-trials to that evoked by Go-trials in task blocks where Stop-stimuli were to be ignored. In addition, region-of-interest analyses comparing the responses to these task-irrelevant Stop-trials, with those to typical relevant Stop-trials, identified separable activity profiles as a function of the task-relevance of the Stop-signal. While occipital areas were mostly blind to the task-relevance of Stop-stimuli, activity in temporo-parietal areas dissociated between task-irrelevant and task-relevant ones. Activity profiles in frontal areas, in turn, were activated mainly by task-relevant Stop-trials, presumably reflecting a combination of triggered top-down attentional influences and inhibitory motor-control processes
Effects of reward on early stimulus processing.
No full text<p>(<b>A</b>) Averaged ERP distribution maps of the difference between congruent potential-reward and congruent no-reward trials reveal reward-induced modulations of the frontal N200, the parietal P300, and the occiptal N200 components. (<b>B</b>) In incongruent trials (collapsed across the two different word-meaning types <i>Wi0</i> and <i>Wi$</i>), the reward-induced positive-polarity effects were substantially attenuated. Gray-shaded areas indicate significant mean-amplitude differences in the respective regions of interest (ROIs; p-values<.05). (<b>C</b>) ERP waveforms for each condition as well as the respective ERP difference waves are shown for selected ROIs (averaged across channels).</p
The Saccadic Re-Centering Bias is Associated with Activity Changes in the Human Superior Colliculus
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