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Executive control

Sunday, October 02nd,   2011 [18:00 - 20:00]

PS_3.023 - Punishing errors increases post-error slowing but does not affect post-error accuracy

Houtman, F. , Van der Borght, L. , Fias, W. & Notebaert, W.

Ghent University

It has been shown that people who are more sensitive for errors demonstrate a different reaction to errors. For example, adults with an obsessive-compulsive disorder show increased post-error slowing (Veale, Sahakian, Owen, & Marks, 1996). In the present study, we manipulated error sensitivity experimentally in an arrow flanker task. Participants were either rewarded for correct trials, or punished for error trials. Moreover, both the reward and the punishment groups were further divided in a high and low reward/punishment condition, resulting in 4 between-subjects conditions. Post-error slowing was observed in the punishment groups but not in the reward groups, indicating that more attention was directed to the errors in the punishment group, in line with the orienting account for post-error slowing (Notebaert et al., 2009). Interestingly, there was post-error accuracy decrease in all groups. This indicates that post-error slowing is not functional and does not improve performance and, more important, that post-error accuracy is dissociable from post-error speed. While reaction times on trial n depend on the amount of attention directed to the action outcome of trial n-1, accuracy on trial n is more directly correlated with accuracy on trial n-1.

PS_3.024 - Switching to worse ? Response suppression studied by change task

Spieser, L. 1, 2, 3 , Casini, L. 1, 3, 2 , Hasbroucq, T. 1, 2, 3 & Burle, B. 1, 2, 3

1 Laboratoire de Neurobiologie de la Cognition, UMR 6155, Marseille
3 Université de Provence, Marseille

In conflicting situations, control of responses activation is crucial in order to provide actions appropriated to the context. By studying those processes using a Simon task, previous studies have led to the development of the activation-suppression model. According to this model, the early activation of the spatially-corresponding response is followed by the inhibition of this response. We test this model using a Simon task, combined with a Change task: on some trials of a classical Simon task, during the subject's reaction time, a change of stimulus color indicates the need to change the response (thus, congruent trials become incongruent, and incongruent trials become congruent). Using different delays between the first stimulus presentation and the color change allow us to investigate the dynamics of the responses activation and inhibition. A non-trivial prediction of the activation-suppression model is that when the color change occurs at a long delay after the stimulus, switching from a congruent to an incongruent response should be easier than from an incongruent to a congruent response, because of the (relative) suppression of the spatially-corresponding response at this moment. First results seem to confirm this prediction.

PS_3.025 - Working memory, executive functions and neurological soft signs in obsessive-compulsive disorder

Jaafari, N. 1 , Descoust, M. 2 , Frasca, M. 2 , Rigalleau, F. 2 & Vibert, N. 2

1 Unité de Recherche Clinique en Psychiatrie, Centre Hospitalier Henri Laborit et Université de Poitiers, Poitiers, France
2 CeRCA, CNRS - Université de Poitiers, Poitiers, France

Obsessive-compulsive disorder (OCD) is a psychiatric disease associated with abnormalities of the orbitofrontal prefrontal cortex. This study was aimed at clarifying the relationships between working memory capacities, executive abilities and neurological soft signs (NSS), i.e. three measures that have been linked to prefrontal brain areas, in OCD patients. Participants were 43 patients and their individually-matched controls. The verbal and visuo-spatial components of participants’ working memory were evaluated using the reading span and the backward location span tests. Executive functions were assessed through selective attention tests involving active inhibition (the Stroop and d2 target crossing tests), tests assessing information retrieval from long-term memory (the verbal fluency and Hayling sentence completion tests), and a task switching test. OCD patients’ working memory spans were both reduced compared to controls. All OCD patients’ executive abilities were impaired, but their performance was particularly low on all tests involving active inhibition processes. NSS were more frequent in OCD patients than in controls, and there was a negative correlation between the OCD patients’ intensity of NSS, their working memory spans and their performance on the Stroop and d2 selective inhibition tests. This suggests that NSS might be used as an index of the prefrontal abnormalities underlying OCD.

PS_3.026 - Social-evaluative stress differentially modulates brain activities for mixing and switching costs

Chang, E. 1 , Lin, C. 2 , Huang, H. 1, 2 , Huang, T. 2 , Tzeng, O. J. 3 & Hung, D. 1

1 Institute of Cognitive Neuroscience. National Central University. Jhongli, Taiwan
2 Brain Research Center. National Chiao-Tung University. Hsinchu, Taiwan
3 Academia Sinica. Taipei, Taiwan

This functional magnetic resonance imaging (fMRI) study examined the acute effect of social-evaluative stress on task switching. Participants performed a switching task under both stressful (negative feedback about performance) and control (no feedback) conditions. Behavioral results indicated a trend of shorter RTs and smaller local switching effect in the stressful than in the control condition. Voxelwise GLM analysis of BOLD signals revealed that while stress modulated activations for global switching effect in visual regions (right middle occipital gyrus and cuneus), it had a wider spread influence on activations for local switching effect across anterior (bilateral putamen; right caudate and medial frontal gyrus) and posterior areas (right middle occipital gyrus, precuneus and cuneus, lingual gyrus ). Interestingly, in the local-effect related region-of-interests (ROIs), activations for single task blocks were smaller in the stressful than in the control condition, whereas activations for repeated trials in the mixed task blocks showed the opposite pattern. On the other hand, in the global-effect related ROIs, activations for switched trials remained constant regardless of stress, while those for repeated trials were larger in the stressful condition. To conclude, task switching requires executive processes that are differentially prone to the influence of social evaluative stress.

PS_3.027 - Obsessive-Compulsive symptoms, Cognitive Self-Consciousness and cognitive inhibition

Mrozowicz, M.

Faculty of Philosophy, Jagiellonian University; Cracow, Poland

Difficulties in the inhibition of irrelevant information or reaction are supposed to be an important aspect of Obsessive-Compulsive Disorder (OCD). Moreover, OCD subjects' cognitive deficits observed in several studies may be accounted for by non-effective attentional resource allocation (especially a tendency to monitor one’s cognitive processes). The aim of the present study was to explore the relation between cognitive inhibition and the intensity of OCD symptoms in a subclinical group. Participants were administered with the Vancouver Obsessive-Compulsive Scale (VOCI) and a battery of tasks measuring inhibitory processes (based on Stroop, Go/No Go, Stop Signal and Navon tasks). The tendency to focus on internal processes was assessed with the Cognitive-Self Consciousness Scale (CSC). The intensity of depressive symptoms (BDI), state and trait anxiety (STAI) were controlled as well. It is expected that measures of inhibition would negatively correlate with VOCI, CSC and STAI scores. Positive correlations between self-reported measures of OCD symptoms, the Cognitive Self-Consciousness Scale and anxiety scale scores are also expected. The data is currently under analysis.

PS_3.028 - Does the phonological buffer represent stimulus-response rules for task-set preparation and maintenance?

van 't Wout, F. , Monsell, S. & Lavric, A.

School of Psychology. University of Exeter. Exeter, UK.

A growing body of evidence suggests that linguistic, and specifically phonological, representations might be involved in task-set preparation and maintenance (e.g. Miyake et al., 2004). But the precise nature of this contribution remains unclear. Accounts of task-switching generally assume that the current task’s stimulus-response (S-R) rules must be elevated to and maintained in a privileged state of activation. The two experiments reported here test the hypothesis that the phonological buffer is used to represent them. To this end, two variables that should reveal phonological buffer involvement - the word length and phonological similarity of the stimulus terms - were manipulated within a task-cueing paradigm. Specifically, participants were required to switch between classifying sets of images depicting nouns of longer or shorter spoken duration (Experiment 1), or between classifying sets of phonologically similar or dissimilar consonants (Experiment 2). The results demonstrate that neither word length nor phonological similarity affected task switching performance, or indeed performance in general. Only at the very start of Experiment 2 were reaction times reliably longer for phonologically similar than dissimilar consonants, suggesting a very transient role of the phonological buffer in representing S-R rules.

PS_3.029 - Role of phonological short-term memory in global but not local task switch costs

Allen, C. & Martin, R.

Department of Psychology. Rice University. Houston, TX, USA.

Previous research has suggested that phonological short-term memory (STM) is involved when self-cueing of task switches is required. In this study, we examined whether semantic STM also plays a role in shifting. Using a predictable, cued shifting paradigm, we assessed the effect of increasing task memory load and of individual differences in both phonological and semantic STM capacity. Older adults were tested on a cued shifting paradigm under low and high memory load conditions, and in both standard and articulatory suppression (AS) conditions. For global switch costs, AS disrupted performance in the high but not the low load condition; in addition, performance in the high load condition was negatively correlated with phonological retention. For local switch costs, AS did not disrupt performance in either load condition; local switch costs showed no relation to any measure of STM capacity. In line with previous research, we hypothesize that a phonological code is used to maintain task sequence in mixed task conditions under high load conditions, and is equally involved in shift and repeat trials; in contrast, semantic STM does not play a critical role in this measure of executive function.

PS_3.030 - How is cognitive control fine-tuned? ERP evidence for reactive and proactive cognitive control

Czernochowski, D. & Saße, J.

Heinrich-Heine-University Düsseldorf

According to the dual mechanisms of control framework (Braver et al., 2007), two alternate routes may lead to correct response selection. When response conflict is detected, reactive control processes can be recruited immediately before the response, at the expense of longer RTs. If advance preparation is feasible, control processes can be recruited proactively to allow for both rapid and correct response selection. Here, informative or uninformative cues were presented in a cued task-switch paradigm, making advance preparation either feasible or not. Event-related potentials (ERPs) were recorded to identify dissociable neural correlates for both control processes. Following informative cues, participants responded about 300 ms faster relative to uninformative cues, suggesting proactive control was recruited successfully. In the corresponding ERPs, a sustained (right-) frontal positivity was observed between 200-500 ms post-cue onset following informative, but not uninformative cues. By contrast, accuracy was high following both types of cues, suggesting that reactive control was recruited successfully. Starting around 200 ms pre-response, the corresponding ERPs revealed a (left-) frontal activity (pre-response negativity) following uninformative relative to informative cues. Both components and performance differences were evident only during mixed-task blocks, consistent with the notion that control processes are recruited selectively to meet higher task demands.

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