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Neurocognitive correlates of Cognitive Control.

Saturday, October 01st,   2011 [08:30 - 10:30]

SY_12. Neurocognitive correlates of Cognitive Control

Colzato, L.

Leiden University, Cognitive Psychology Unit & Leiden Institute for Brain and Cognition, Leiden, The Netherlands

Frontal lobe circuits have a crucial role in the cognitive control of our thoughts and goal-directed behaviour. At least four control functions can be distinguished: ?shifting? (also called ?flexibility?) between tasks, mental sets and ?updating? (and monitoring of) working memory (WM) representations, the ?inhibition? of prepotent responses, decision-making and interference control. Apart from being empirically separable, they also seem to rely on different cortical structures. To give a complete overview of this complex phenomenon, this symposium will be interdisciplinary. Cognitive control will be presented from different perspectives and using different methodologies, behavioral, hormonal, pharmacological, clinical, genetic and brain-imaging studies.



SY_12.1 - Estrogen modulates inhibitory control in healthy human females: Evidence from the inhibition of return paradigm

Colzato, L.

Leiden University, Cognitive Psychology Unit & Leiden Institute for Brain and Cognition, Leiden, The Netherlands

Animal studies point to a role of estrogen in explaining gender differences in striatal dopaminergic functioning, but evidence from human studies is still lacking. Given that dopamine is crucial for attentional flexibility, estrogen may have a specific impact on the inhibition of return (IOR) effect, which refers to the fact that people are slower to detect a target if it appears in a previously attended location. We compared performance on the IOR task with stimulus-onset asynchronies (SOAs) between attention cue and target of 150-1200 ms in young women across the three phases of their menstrual cycle (salivary estradiol and progesterone concentrations were assessed) and in young men, at different sessions separated by 10 days, according to the corresponding time interval in days between the different phases in women. First, women were higher magnitude of IOR in their follicular phase (FP), which is associated with higher estradiol levels dopamine turnover rates, than in their luteal or menstruation phase. Second, women showed higher magnitude of IOR than men only in the FP. Our results support the idea that striatal DA levels promote IOR, presumably by biasing the interplay between prefrontal and striatal networks towards greater cognitive flexibility. The variation of estrogen levels across the menstrual cycle may account for our observations of gender differences in IOR, suggesting that such differences are variable and state-dependent but not structural.

SY_12.2 - The role of cortico-striatal networks in flexible decision making

Forstmann, B. U.

Cognitive Science Center Amsterdam, University of Amsterdam, the Netherlands

For many everyday life decisions, people face the dilemma that fast decisions tend to be error-prone, whereas accurate decisions tend to be relatively slow. In other words, people can choose to respond more quickly at the cost of making more errors, a phenomenon known as the speed-accuracy tradeoff (SAT). In this talk I discuss the neural substrate of SAT using data from functional magnetic resonance imaging (fMRI), diffusion tensor imaging (DTI), and ultra-high resolution 7T MRI. In a series of experiments participants were presented cues that indicated different requirements for response speed. Application of the Linear Ballistic Accumulator model (LBA; Brown & Heathcote, 2009) confirmed that these cues selectively affected response thresholds. Individual LBA parameters were then correlated with functional and structural MRI measures, revealing the involvement of the pre-supplementary motor area (pre-SMA) in concert with the striatum; this finding is consistent with the fact that excitatory signals from pre-SMA to striatum release the motor system from inhibition, thus facilitating faster but possibly premature actions. The present results suggest that individual differences in both brain function and brain structure translate to individual differences in the efficacy with which people change response thresholds.

SY_12.3 - The yin and yang of cognitive control: evidence from behavioral-genetics studies

Hommel, B.

Leiden University, Cognitive Psychology Unit & Leiden Institute for Brain and Cognition, Leiden, The Netherlands

Increasing evidence suggests that cognitive control emerges from the interplay between two dopaminergic pathways: a (mesocortical) prefrontal and a (nigro-)striatal pathway. I will summarize and try to integrate a number of recent behavioral-genetics studies from our lab that used various tasks (like task-switching, inhibition of return, stop-signal, and attentional blink tasks) to characterize how the two pathways operate and interact. Taken together, these studies demonstrate a kind of double-dissociation between the functional responsibilities of these pathways: Whereas the prefrontal pathway takes care of the maintenance of goals and the update of goal-related information, the striatal pathway supports cognitive flexibility.

SY_12.4 - The effect of dopamine agonists on risk behavior in Parkinson’s disease patients with and without impulse control disorder

van den Wildenberg, W. P.

Universiteit van Amsterdam, Amsterdam Center for the Study of Adaptive Control in Brain and Behaviour (ACACia), Psychology Department, Amsterdam, The Netherlands

Dopamine agonist treatment is associated with the emergence of impulse control disorder (ICD) in Parkinson’s disease (PD). Agonists preferentially alter mesocorticolimbic dopamine pathways, which modulate risk-taking behavior. We hypothesized that dopamine agonists would increase risk-taking behavior in PD, especially among a vulnerable subset of patients who developed ICD concomitant with dopamine agonist use. PD patients with agonist-induced ICD (PDICD; n=22) and PD controls without ICD (PD-C; n=19) performed a variant of the Balloon Analogue Risk Task (BART) in which participants allowed balloons to inflate to earn higher rewards while risking the chance that the balloon would pop. The probability that balloons would pop was manipulated to assess sensitivity to negative consequences. Patients were tested separately in “on” and in “off” dopamine agonist states. In the off dopamine agonist state, PD-ICD and PD-C groups risked a similar number of balloon inflations to earn rewards. In the on agonist state, PD-ICD risked significantly more balloon inflations than PD-C to obtain rewards. Both groups risked fewer balloon inflations when the risk of balloon popping was higher and on trials immediately following a popped balloon. PD patients with ICD show a propensity toward risky decisions when on their dopamine agonist medication. The increase in risktaking appears driven by efforts to obtain higher rewards rather than by a reduced sensitivity to the effects of negative consequences. These findings suggest that changes in risk processing as a result of dopamine agonist use may underlie clinical symptoms of ICD. Our results also add behavioral support to the emerging view that the clinical expression of ICD reflects converging genetic, environmental, and pharmacological influences on dopamine and mesocorticolimbic function.

SY_12.5 - Exogenous and endogenous strategies in dual task performance

Cohen, A. & Israel, M.

The Hebrew University, Department of Psychology, Jerusalem, Israel

Although it has been known for a long time that dual task performance is affected by strategic processes, research in recent decades focused on structural causes for dual task deficit. Consequently, dual task costs in paradigms such as the Psychological Refractory Period (PRP) paradigm have been attributed to structural causes. We present experiments that show that there exist powerful task-based strategic processes. Some such strategies are executed intentionally, but some strategies are triggered exogenously (i.e., without intention) and may cause costs even in situations where the two tasks could be performed without costs. We show that such exogenous strategies rather than structural reasons may lead to the PRP effect. We end with a discussion on the dual nature of strategic (flexible) processes that are performed exogenously (inflexibly).

SY_12.6 - On the impact of individual differences between key nodes of response inhibition

Jahfari, S.

Cognitive Science Center Amsterdam, University of Amsterdam, the Netherlands

How does the brain regulate the need for control? Recent literature has identified key cortical and sub-cortical areas involved in response inhibition and proactive control in anticipation of a stop. At the same time, several studies have shown that dopamine in the prefrontal cortex (PFC) modulates core cognitive processes such as working memory and executive control. For example, the genetic variability of the catechol-O-methyltransverase (COMT) gene has been related to cognitive flexibility for individuals with low levels of dopamine in the PFC (val/val homozygotes), and to cognitive stability for individuals with high levels of dopamine in the PFC (val/met homozygotes). However, little is known about the impact of response strategies on proactive control, or how the variability of dopamine in the PFC might help explain the observed individual differences. During this talk, I will present some initial fMRI connectivity data on brain networks essential for the process of cognitive control, and discuss some recent findings suggesting that genetic differences in the COMT val158 polymorphism affect the behavioral- and key neural indices that underlie proactive control and response inhibition.

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