Browsing by Subject "Stroop Test"

Now showing 1 - 4 of 4
  • Thumbnail Image
    ItemOpen Access
    Cross-modal stimulus conflict: the behavioral effects of stimulus input timing in a visual-auditory Stroop task.
    (PLoS One, 2013) Donohue, Sarah E; Appelbaum, Lawrence G; Park, Christina J; Roberts, Kenneth C; Woldorff, Marty G
    Cross-modal processing depends strongly on the compatibility between different sensory inputs, the relative timing of their arrival to brain processing components, and on how attention is allocated. In this behavioral study, we employed a cross-modal audio-visual Stroop task in which we manipulated the within-trial stimulus-onset-asynchronies (SOAs) of the stimulus-component inputs, the grouping of the SOAs (blocked vs. random), the attended modality (auditory or visual), and the congruency of the Stroop color-word stimuli (congruent, incongruent, neutral) to assess how these factors interact within a multisensory context. One main result was that visual distractors produced larger incongruency effects on auditory targets than vice versa. Moreover, as revealed by both overall shorter response times (RTs) and relative shifts in the psychometric incongruency-effect functions, visual-information processing was faster and produced stronger and longer-lasting incongruency effects than did auditory. When attending to either modality, stimulus incongruency from the other modality interacted with SOA, yielding larger effects when the irrelevant distractor occurred prior to the attended target, but no interaction with SOA grouping. Finally, relative to neutral-stimuli, and across the wide range of the SOAs employed, congruency led to substantially more behavioral facilitation than did incongruency to interference, in contrast to findings that within-modality stimulus-compatibility effects tend to be more evenly split between facilitation and interference. In sum, the present findings reveal several key characteristics of how we process the stimulus compatibility of cross-modal sensory inputs, reflecting stimulus processing patterns that are critical for successfully navigating our complex multisensory world.
  • Thumbnail Image
    ItemOpen Access
    Effects of adult age and blood pressure on executive function and speed of processing.
    (Experimental aging research, 2010-04) Bucur, Barbara; Madden, David J
    Previous research has established that the effects of chronically increased blood pressure (BP) on cognition interact with adult age, but the relevant cognitive processes are not well defined. In this cross-sectional study, using a sample matched for age, years of education, and sex, 134 individuals with either normal BP (n = 71) or chronically high BP (n = 63) were categorized into younger (19-39 years), middle-aged (41-58 years), and older (60-79 years) groups. Using a between-subjects analysis of variance (ANOVA), covarying for race and years of education, composite measures of executive function and perceptual speed both exhibited age-related decline. The executive function measure, however, was associated with a differential decline in high BP older adults. This result held even when the executive function scores were covaried for speed, demonstrating an independent, age-related effect of higher BP on executive function.
  • Thumbnail Image
    ItemOpen Access
    Effects of varenicline and cognitive bias modification on neural response to smoking-related cues: study protocol for a randomized controlled study.
    (Trials, 2014-10-07) Attwood, Angela S; Williams, Tim; Adams, Sally; McClernon, Francis J; Munafò, Marcus R
    BACKGROUND: Smoking-related cues can trigger drug-seeking behaviors, and computer-based interventions that reduce cognitive biases towards such cues may be efficacious and cost-effective cessation aids. In order to optimize such interventions, there needs to be better understanding of the mechanisms underlying the effects of cognitive bias modification (CBM). Here we present a protocol for an investigation of the neural effects of CBM and varenicline in non-quitting daily smokers. METHODS/DESIGN: We will recruit 72 daily smokers who report smoking at least 10 manufactured cigarettes or 15 roll-ups per day and who smoke within one hour of waking. Participants will attend two sessions approximately one week apart. At the first session participants will be screened for eligibility and randomized to receive either varenicline or a placebo over a seven-day period. On the final drug-taking day (day seven) participants will attend a second session and be further randomized to one of three CBM conditions (training towards smoking cues, training away from smoking cues, or control training). Participants will then undergo a functional magnetic resonance imaging scan during which they will view smoking-related pictorial cues. Primary outcome measures are changes in cognitive bias as measured by the visual dot-probe task, and neural responses to smoking-related cues. Secondary outcome measures will be cognitive bias as measured by a transfer task (modified Stroop test of smoking-related cognitive bias) and subjective mood and cigarette craving. DISCUSSION: This study will add to the relatively small literature examining the effects of CBM in addictions. It will address novel questions regarding the neural effects of CBM. It will also investigate whether varenicline treatment alters neural response to smoking-related cues. These findings will inform future research that can develop behavioral treatments that target relapse prevention. TRIAL REGISTRATION: Registered with Current Controlled Trials: ISRCTN65690030. Registered on 30 January 2014.
  • Thumbnail Image
    ItemOpen Access
    Reward associations reduce behavioral interference by changing the temporal dynamics of conflict processing.
    (PLoS One, 2013) Krebs, Ruth M; Boehler, Carsten N; Appelbaum, Lawrence G; Woldorff, Marty G
    Associating 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.