Response inhibition is essential for navigating everyday life. Its derailment is considered integral to numerous neurological and psychiatric disorders, and more generally, to a wide range of... Show moreResponse inhibition is essential for navigating everyday life. Its derailment is considered integral to numerous neurological and psychiatric disorders, and more generally, to a wide range of behavioral and health problems. Response-inhibition efficiency furthermore correlates with treatment outcome in some of these conditions. The stop-signal task is an essential tool to determine how quickly response inhibition is implemented. Despite its apparent simplicity, there are many features (ranging from task design to data analysis) that vary across studies in ways that can easily compromise the validity of the obtained results. Our goal is to facilitate a more accurate use of the stop-signal task. To this end, we provide twelve easy-to-implement consensus recommendations and point out the problems that can arise when these are not followed. Furthermore we provide user-friendly open-source resources intended to inform statistical-power considerations, facilitate the correct implementation of the task, and assist in proper data analysis. Show less
The fact that tyrosine increases dopamine availability that, in turn, may enhance cognitive performance has led to numerous studies on healthy young participants taking tyrosine as a food... Show moreThe fact that tyrosine increases dopamine availability that, in turn, may enhance cognitive performance has led to numerous studies on healthy young participants taking tyrosine as a food supplement. As a result of this dietary intervention, participants show performance increases in working memory and executive functions. However, the potential association between habitual dietary tyrosine intake and cognitive performance has not been investigated to date. The present study aims at clarifying the association of episodic memory (EM), working memory (WM) and fluid intelligence (Gf), and tyrosine intake in younger and older adults. To this end, we acquired habitual tyrosine intake (food frequency questionnaire) from 1724 participants of the Berlin Aging Study II (1383 older adults, 341 younger adults) and modelled its relations to cognitive performance assessed in a broad battery of cognitive tasks using structural equation modeling. We observed a significant association between tyrosine intake and the latent factor capturing WM, Gf, and EM in the younger and the older sample. Due to partial strong factorial invariance between age groups for a confirmatory factor analysis on cognitive performance, we were able to compare the relationship between tyrosine and cognition between age groups and found no difference. Above and beyond previous studies on tyrosine food supplementation the present result extend this to a cross-sectional association between habitual tyrosine intake levels in daily nutrition and cognitive performance (WM, Gf, and EM). This corroborates nutritional recommendations that are thus far derived from single-dose administration studies. Show less
Emerging research suggests that individuals experience vicarious social pain (i.e., ostracism). It has been proposed that observing ostracism increases activity in the insula and in the prefrontal... Show moreEmerging research suggests that individuals experience vicarious social pain (i.e., ostracism). It has been proposed that observing ostracism increases activity in the insula and in the prefrontal cortex (PFC), two key brain regions activated by directly experiencing ostracism. Here, we assessed the causal role of the insula and PFC in modulating neural activity in these areas by applying transcutaneous Vagus Nerve Stimulation (tVNS), a new non-invasive and safe method to stimulate the vagus nerve that has been shown to activate the insula and PFC. A single-blind, sham-controlled, within-subjects design was used to assess the effect of on-line (i.e., stimulation overlapping with the critical task) tVNS in healthy young volunteers (n = 24) on the prosocial Cyberball game, a virtual ball-tossing game designed to measure prosocial compensation of ostracism. Active tVNS did not increase prosocial helping behavior toward an ostracized person, as compared to sham (placebo) stimulation. Corroborated by Bayesian inference, we conclude that tVNS does not modulate reactions to vicarious ostracism, as indexed by performance in a Cyberball game. Show less
Colzato, L.S.; Rover, M. de; Wildenberg, W.P.M. van den; Nieuwenhuis, S. 2013
BACKGROUND The brain-derived neurotrophic factor (BDNF) is a key protein in maintaining neuronal integrity. The BDNF gene is thought to play an important role in the pathophysiology of mood and... Show moreBACKGROUND The brain-derived neurotrophic factor (BDNF) is a key protein in maintaining neuronal integrity. The BDNF gene is thought to play an important role in the pathophysiology of mood and anxiety disorders. The aim of this study was to investigate, for the first time in a single study, the association between BDNF Val(66)Met polymorphism, anxiety, alcohol consumption, and cortisol stress response. METHOD 98 healthy university students (54 females and 44 males), genotyped for the Val(66)Met polymorphism, participated in a physical-stress procedure (cold pressure test, CPT) after having been informed that they would undergo a painful experience. Indices of anxiety and of stress were collected from repeated measurement of salivary cortisol, blood pressure, and heart rate. RESULTS BDNF Met carriers, were more anxious during the CPT (p<0.001), drank more alcohol per week, (p<0.05), and showed significantly higher anticipatory cortisol response (p<0.05), but not in response to the CPT, than Val/Val homozygotes. The association of BDNF Val(66)Met polymorphism with HPA axis reactivity to stress was not modulated by gender. These results suggest that Met carriers are particularly sensitive in anticipating stressful events, which extends previous findings on the moderating role of the BDNF Val(66)Met polymorphism in the face of stressful life events. Show less
Colzato, L.S.; Does, A.J.W. van der; Kouwenhoven, C.; Elzinga, B.M.; Hommel, B. 2011
The present fMRI study tested the assumption that a single pairing of a stimulus and a logically unrelated response is sufficient for binding the corresponding stimulus and response codes into an... Show moreThe present fMRI study tested the assumption that a single pairing of a stimulus and a logically unrelated response is sufficient for binding the corresponding stimulus and response codes into an event representation (event file) that is automatically retrieved upon processing of at least one of its components. In particular, we investigated whether repeating a face or a house stimulus and/or a left or a right manual response induces the automatic retrieval of the response or stimulus that it previously accompanied. ROI analyses of fusiform face area, parahippocampal place area, and right and left motor cortex revealed that repeating one component of a previously encountered stimulus-response episode leads to the suppression of cortical areas processing the other components, suggesting that these components were indeed automatically retrieved and conflicted with ongoing processing. The particular pattern obtained is consistent with predictions from diffusion models of decision making, which suggest a crucial role of local competition in response selection. Show less
Colzato, L.S.; Wildenberg, W.P.M. van den; Does, A.J.W. van der; Hommel, B. 2010
Various psychiatric disorders are characterized by elevated levels of impulsivity. Although extensive evidence supports a specific role of striatal, but not frontal dopamine (DA) in human... Show moreVarious psychiatric disorders are characterized by elevated levels of impulsivity. Although extensive evidence supports a specific role of striatal, but not frontal dopamine (DA) in human impulsivity, recent studies on genetic variability have raised some doubts on such a role. Importantly, impulsivity consists of two dissociable components that previous studies have failed to separate: functional and dysfunctional impulsivity. We compared participants with a genetic predisposition to have relatively high striatal DA levels (DAT1 9-repeat carriers, DRD2 C957T T/T homozygotes, and DRD4 7-repeat carriers) with participants with other genetic predispositions. We predicted that the first group would show high scores of dysfunctional, but not functional, self-reported impulsivity and greater difficulty in inhibiting a behavioral response to a stop-signal, a behavioral measure of impulsivity. In a sample of 130 healthy adults, we studied the relation between DAT1, DRD4, and C957T polymorphism at the DRD2 gene (polymorphisms related to striatal DA) and catechol-Omethyltransferase (COMT) Val158Met (a polymorphism related to frontal DA) on self-reported dysfunctional and functional impulsivity, assessed by the Dickman impulsivity inventory (DII), and the efficiency of inhibitory control, assessed by the stop-signal paradigm. DRD2 C957T T/T homozygotes and DRD4 7-repeat carriers indeed had significantly higher scores on self-reported dysfunctional, but not functional, impulsivity. TIT homozygotes were also less efficient in inhibiting prepotent responses. Our findings support the claim that dopaminergic variation affects dysfunctional impulsivity. This is in line with the notion that the over-supply of striatal DA might weaken inhibitory pathways, thereby enhancing the activation of, and the competition between responses. (C) 2010 IBRO. Published by Elsevier Ltd. All rights reserved. Show less
