{"responseData":{"translatedText":"google translate","match":0.99},"quotaFinished":false,"mtLangSupported":null,"responseDetails":"","responseStatus":200,"responderId":null,"exception_code":null,"matches":[{"id":"434077915","segment":"google translate","translation":"google translate","source":"nl-NL","target":"en-GB","quality":74,"reference":null,"usage-count":2,"subject":"All","created-by":"Wikipedia","last-updated-by":"Wikipedia","create-date":"2023-11-09 22:17:39","last-update-date":"2023-11-09 22:17:39","match":0.99,"penalty":0},{"id":"657515216","segment":"Google Translate","translation":"Google Translate","source":"nl-NL","target":"en-GB","quality":74,"reference":null,"usage-count":2,"subject":"","created-by":"MateCat","last-updated-by":"MateCat","create-date":"2025-07-01 14:36:54","last-update-date":"2025-07-01 14:36:54","match":0.98,"penalty":0},{"id":"447617128","segment":"google translate","translation":"How do cannabis and cocaine intake affect human neurocognitive functions? And do they have the same effects in every individual? Those are the main questions that were asked in this thesis. Many addiction researchers study these questions by investigating psychological processes and brain mechanisms both at macro and molecular levels in animals and humans. All of us hope to shed light on different parts of the puzzle with the aim of elucidating the mechanisms of drugs in the brain, motivational aspects of drug use, and changes in the brain in the transition from recreational drug use to addiction. The answer to why people use drugs of abuse might even lie in the answers to those more theoretical questions. The research described in this thesis only covers a niche, namely acute effects on measures of cognitive control. To this end we assessed a number of relatively recent, but also some more established cognitive paradigms. The aim of this chapter is to summarize the main results from the preceding chapters and discuss them in a broader context.\nThe chapters in this thesis are derived from two separate studies in which THC or placebo (Chapter 3) or cocaine, cannabis, and placebo (Chapter 4 until Chapter 7) were administered in a placebo-controlled manner in healthy individuals who were regular users. The majority of the chapters focused on drug effects on measures of cognitive action control. More specifically, we looked into performance (error)-monitoring, response inhibition, and reversal learning. In a number of those studies (Chapter 3, 4 and 6), behavioural measures were complemented with brain electrophysiological markers of those processes, so-called event related potentials (ERPs). In final chapter (Chapter 7) we also investigated cognitive control of social\/emotional behaviour by looking at social action tendencies. An overarching goal of this thesis was to identify factors that could explain interindividual differences in effects of drugs. We therefore looked at the role of individual differences in genetic polymorphisms and traits associated with impulsivity and novelty seeking.\nOverall the various studies presented in this thesis support the hypothesis that cocaine and cannabis have profound effects on measures of cognitive control (see Table 8.1 for an overview). There were profound differences between individuals. However, the extent to which those differences could be linked to the factors investigated in this study (personality and genetics) was limited. \nTable 8.1 Overview of affected cognitive functions after acute administration of cannabis and cocaine relative to placebo condition, \u2191 = improvement, \u2193 = impairment, \u2194 no effect.\nFunction\tCannabis\tCocaine\nError-monitoring (ERN)\t\u2193\t\u2191\n\t\t\nConflict monitoring (NoGo-N2)\t\u2194\t\u2194\nEarly visual processing\t\u2194\t\u2194\nSelective attention\t\u2193\t\u2191\nPlanning\t\u2193\t\u2194\nAttentional Shifting\t\u2193\t\u2194\nProcessing speed\t\u2193\t\u2191\nResponse inhibition\t\u2193\t\u2191\nReversal learning\t\u2193\t\u2191\nValence dependent reversal learning\t\u2194\t\u2194\nSocial action control\t\u2193\t\u2194\n\nIn Chapter 3 and Chapter 4 we used an adapted version of the Erikson Flanker test while concurrently recording event related potentials (ERPs) to assess electrophysiological correlates of performance monitoring. The study in Chapter 3 was the first study in which it was shown that the administration of tetrahydrocannabinol (THC) impairs performance monitoring reflected by reducingthe error related negativity (ERN) in a group of ten users. In Chapter 4, we aimed to replicate this result in the Impulsive Brain project and succeeded. Also in Chapter 4 we could demonstrate that cannabis lowered the ERN. We were furthermore the first to demonstrate that cocaine enhanced performance monitoring by enhancing the ERN. In addition, no effects of either drug on the Pe and post-error slowing were found. We also found that cannabis decreased the P300 ERP, while cocaine enhanced the P300 ERP. In Chapter 5 we employed a reversal learning paradigm in order to investigate potential differential effects in learning from reward vs punishment reversals. In contrast to our hypothesis, we found no evidence for a role of cocaine and cannabis in valence-dependent reversal learning. Overall performance differences were observed where cannabis negatively impacted learning, and cocaine improved reversal learning. Planning and attentional switching was investigated as well in order to investigate the specificity of the reversal learning findings. Cannabis impaired both functions, but cocaine had no effect. The results suggested that whereas cannabis leads to a general impairment across cognitive control functions, cocaine\u2019s effect were much more specific to reversal learning.\nIn Chapters 4 and 5, we additionally investigated whether two dopaminergic candidate genes, the COMT val158Met and DRD2 taq1a polymorphism, could explain interindividual differences in drug responses on performance monitoring or reversal learning. In Chapter 4, we found no interaction between drugs and the two candidate genes on the performance monitoring related ERPs, or on post-error slowing. Notably, the results did reveal that the DRD2 A1 carriers performed, compared to the A2\/A2 group, worse on error-monitoring as indicated by a reduced ERN. In Chapter 5 these genes were further investigated in relation to reversal learning. For this domain, we found evidence that the A1 variant of the DRD2 gene demonstrated a larger cocaine-induced improvement on reversal learning. \nSimilar to the results in Chapter 4 and 5, findings detailed in Chapter 6 indicated opposing effects of cannabis and cocaine on response inhibition in a standard Go\/NoGo task. Concurrent measurement of inhibition related ERPs enabled us to demonstrate that the effects of cannabis and cocaine were opposite; cocaine enhances the NoGo-P300 where cannabis lowers its amplitude. Cannabis furthermore resulted in a general lowering of the P300 ERP suggesting that general information processing of the stimuli was also negatively affected. We also explored how individual differences in trait Impulsivity and Novelty seeking were related to drug-induced effects on response inhibition related ERPs. The findings suggested that these two personality traits do not explain differences in acute effects of cannabis and cocaine on response inhibition.   \nFinally, in Chapter 7 we looked at social approach avoidance behaviour in interaction with the MAOA VNTR polymorphism. With regard to cannabis we showed that carriers of the low-activity (L-MAOA) genotype, often associated with a higher risk for developing problems in socio-emotional behaviour, demonstrated an approach bias to faces with an angry appearance. This approach was not seen in the high-activity genotype group. In contrast to our hypothesis, the genotype did not modulate social approach behaviour after cocaine. In fact, cocaine did not affect social approach behaviour at all.\n","source":"nl-NL","target":"en-US","quality":"74","reference":null,"usage-count":2,"subject":"General","created-by":"MateCat","last-updated-by":"","create-date":"2015-04-16 14:05:59","last-update-date":"2015-04-16 14:05:59","match":0.98,"penalty":0}]}