Trevor W. Robbins

Bio: Trevor W. Robbins is an academic researcher from University of Cambridge. The author has contributed to research in topics: Prefrontal cortex & Impulsivity. The author has an hindex of 231, co-authored 1137 publications receiving 164437 citations. Previous affiliations of Trevor W. Robbins include Centre national de la recherche scientifique & Massachusetts Institute of Technology.

Effect of lysergic acid diethylamide (LSD) on reinforcement learning in humans

Abstract: The non-selective serotonin 2A (5-HT2A) receptor agonist lysergic acid diethylamide (LSD) holds promise as a treatment for some psychiatric disorders. Psychedelic drugs such as LSD have been suggested to have therapeutic actions through their effects on learning. The behavioural effects of LSD in humans, however, remain largely unexplored. Here we examined how LSD affects probabilistic reversal learning in healthy humans. Healthy volunteers received intravenous LSD (75μg in 10 mL saline) or placebo (10mL saline) in a within-subjects design and completed a probabilistic reversal learning task. Participants had to learn through trial and error which of three stimuli was rewarded most of the time, and these contingencies switched in a reversal phase. Computational models of reinforcement learning were fitted to the behavioural data to assess how LSD affected the updating (“learning rates”) and deployment (“reinforcement sensitivity”) of value representations during choice, as well as “stimulus stickiness”, which assays choice repetition irrespective of reinforcement history. Conventional measures assessing sensitivity to immediate feedback (“win-stay” and “lose-shift” probabilities) were unaffected, whereas LSD increased the impact of the strength of initial learning on perseveration. Computational modelling revealed that the most pronounced effect of LSD was enhancement of the reward learning rate. The punishment learning rate was also elevated. Stimulus stickiness was decreased by LSD, reflecting heightened exploratory behaviour, while reinforcement sensitivity was unaffected. Increased reinforcement learning rates suggest LSD induced a state of heightened plasticity. These results indicate a potential mechanism through which revision of maladaptive associations could occur in the clinical application of LSD. Significance statement The psychedelic (“mind-manifesting”) drug LSD holds promise for the treatment of some psychiatric disorders. Theories have postulated its therapeutic potential centres on enhancing learning and flexible thinking. Here we provide substantiating empirical evidence by examining the computations underlying behaviour as healthy volunteers learned through trial and error under LSD. Viewing choice as based on representations of an action’s value, LSD increased the speed at which value was updated following feedback, which was more pronounced following reward than punishment. Behaviour was also more exploratory under LSD, irrespective of the outcome of actions. These results indicate that LSD impacted a fundamental belief-updating process inherent in the brain which can be leveraged to revise maladaptive associations characteristic of a range of mental disorders.

Research data supporting "Compulsivity reveals a novel dissociation between action and confidence"

Abstract: Original and unprocessed data is provided in support of the article "Compulsivity reveals a novel dissociation between action and confidence". The article was accepted for publication in 2017 in the journal "Neuron". The data relate to the main findings of the study originating from the predictive-inference task described in the manuscript. Electronic supporting information is available from the publisher.

GABRB1 Single Nucleotide Polymorphism Associated with Altered Brain Responses (but not Performance) during Measures of Impulsivity and Reward Sensitivity in Human Adolescents

Abstract: Variations in genes encoding several GABAA receptors have been associated with human drug and alcohol abuse. Among these, a number of human studies have suggested an association between GABRB1, the gene encoding GABAA receptor 1 subunits, with alcohol dependence, both on its own and comorbid with other substance dependence and psychiatric illnesses. In the present study, we hypothesised that the GABRB1 genetically-associated increased risk for developing alcoholism may be associated with impaired behavioral control and altered sensitivity to reward, as a consequence of altered brain function. Exploiting the IMAGEN database (Schumann et al, 2010), we explored in a human adolescent population whether possession of the minor (T) variant of the single nucleotide polymorphism rs2044081 is associated with performance of tasks measuring aspects of impulsivity, and reward sensitivity that are implicated in drug and alcohol abuse. Allelic variation did not associate with altered performance in either a stop-signal task (SST), measuring one aspect of impulsivity, or a monetary incentive delay (MID) task assessing reward anticipation. However, increased fMRI BOLD response in the right hemisphere 58 inferior frontal gyrus, left hemisphere caudate/insula, and left hemisphere inferior temporal gyrus during MID performance was higher in the minor (T) allelic group. In contrast, during SST performance, the BOLD response found in the right hemisphere supramarginal gyrus, right hemisphere lingual and left hemisphere inferior parietal gyrus indicated reduced responses in the minor genotype. We suggest that β1-containing GABAA receptors may play a role in excitability of brain regions important in controlling reward-related behavior, which may contribute to susceptibility to addictive behavior.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Control of goal-directed and stimulus-driven attention in the brain

Abstract: We review evidence for partially segregated networks of brain areas that carry out different attentional functions. One system, which includes parts of the intraparietal cortex and superior frontal cortex, is involved in preparing and applying goal-directed (top-down) selection for stimuli and responses. This system is also modulated by the detection of stimuli. The other system, which includes the temporoparietal cortex and inferior frontal cortex, and is largely lateralized to the right hemisphere, is not involved in top-down selection. Instead, this system is specialized for the detection of behaviourally relevant stimuli, particularly when they are salient or unexpected. This ventral frontoparietal network works as a 'circuit breaker' for the dorsal system, directing attention to salient events. Both attentional systems interact during normal vision, and both are disrupted in unilateral spatial neglect.

An integrative theory of prefrontal cortex function

Abstract: ▪ Abstract The prefrontal cortex has long been suspected to play an important role in cognitive control, in the ability to orchestrate thought and action in accordance with internal goals. Its neural basis, however, has remained a mystery. Here, we propose that cognitive control stems from the active maintenance of patterns of activity in the prefrontal cortex that represent goals and the means to achieve them. They provide bias signals to other brain structures whose net effect is to guide the flow of activity along neural pathways that establish the proper mappings between inputs, internal states, and outputs needed to perform a given task. We review neurophysiological, neurobiological, neuroimaging, and computational studies that support this theory and discuss its implications as well as further issues to be addressed

Chapter 11 Working memory

Abstract: Publisher Summary This chapter focuses on the modern notion of short-term memory, called working memory. Working memory refers to the temporary maintenance of information that was just experienced or just retrieved from long-term memory but no longer exists in the external environment. These internal representations are short-lived, but can be maintained for longer periods of time through active rehearsal strategies, and can be subjected to various operations that manipulate the information in such a way that makes it useful for goal-directed behavior. Working memory is a system that is critically important in cognition and seems necessary in the course of performing many other cognitive functions, such as reasoning, language comprehension, planning, and spatial processing. This chapter demonstrates the functional importance of dopamine to working memory function in several ways. Elucidation of the cognitive and neural mechanisms underlying human working memory is an important focus of cognitive neuroscience and neurology for much of the past decade. One conclusion that arises from research is that working memory, a faculty that enables temporary storage and manipulation of information in the service of behavioral goals, can be viewed as neither a unitary, nor a dedicated system. Data from numerous neuropsychological and neurophysiological studies in animals and humans demonstrates that a network of brain regions, including the prefrontal cortex, is critical for the active maintenance of internal representations.