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.

Reconciling the Role of Serotonin in Behavioral Inhibition and Aversion: Acute Tryptophan Depletion Abolishes Punishment-Induced Inhibition in Humans

Abstract: The neuromodulator serotonin has been implicated in a large number of affective and executive functions, but its precise contribution to motivation remains unclear. One influential hypothesis has implicated serotonin in aversive processing; another has proposed a more general role for serotonin in behavioral inhibition. Because behavioral inhibition is a prepotent reaction to aversive outcomes, it has been a challenge to reconcile these two accounts. Here, we show that serotonin is critical for punishment-induced inhibition but not overall motor response inhibition or reporting aversive outcomes. We used acute tryptophan depletion to temporarily lower brain serotonin in healthy human volunteers as they completed a novel task designed to obtain separate measures of motor response inhibition, punishment-induced inhibition, and sensitivity to aversive outcomes. After a placebo treatment, participants were slower to respond under punishment conditions compared with reward conditions. Tryptophan depletion abolished this punishment-induced inhibition without affecting overall motor response inhibition or the ability to adjust response bias in line with punishment contingencies. The magnitude of reduction in punishment-induced inhibition depended on the degree to which tryptophan depletion reduced plasma tryptophan levels. These findings extend and clarify previous research on the role of serotonin in aversive processing and behavioral inhibition and fit with current theorizing on the involvement of serotonin in predicting aversive outcomes.

The effects of chronic administration of hydrocortisone on cognitive function in normal male volunteers.

Abstract: Rationale: Corticosteroids are elevated in certain neuropsychiatric disorders and this may contribute to the neuropsychological impairments reported in these disorders. Objective: To examine the effects of hydrocortisone on learning, memory and executive function. Methods: Hydrocortisone 20 mg was administered twice daily for 10 days to normal male volunteers in a randomized, placebo control, crossover, within-subject design. Learning, memory and executive function were measured using selected subtests from the Cambridge Neuropsychological Test Automated Battery. Results: Hydrocortisone caused impairments of visuo-spatial memory. These included increased within search errors and impaired use of strategies on the spatial working memory subtest. In addition, administration of hydrocortisone was associated with more errors in the paired associate learning subtest, although no effect was found on the Tower of London. Hydrocortisone speeded response latencies in certain tests (pattern and spatial recognition memory). Conclusion: These results indicate that chronic administration of hydrocortisone leads to deficits in certain tests of cognitive function sensitive to frontal lobe dysfunction and may contribute to the cognitive impairment reported in certain neuropsychiatric disorders.

A role for mesencephalic dopamine in activation: commentary on Berridge (2006)

Abstract: Ideas about the functions of the central dopamine (DA) system may seem to have evolved quite considerably in the last decade. While the theoretical debate based on classic neuropsychopharmacological approaches has become much more sophisticated and refined, perhaps the major new concepts have derived from (1) electrophysiological observations that fast phasic firing of cells in the ventral tegmental area appear to model an error prediction signal relevant to Pavlovian or temporal difference learning models (Schultz 2002), and from (2) the relative contributions of such phasic responses with the tonic mode of action of the same DA systems (Goto and Grace 2005). Both of these empirical advances were also matched by theoretical refinement; for example, in the domain of human cognitive neuroscience, the study of the role of DA in reinforcement learning and “error prediction” learning has become highly fashionable (see, e.g., Montague et al. 2004; Frank and O’Reilly 2006) and the tonic–phasic distinction has been a major new construct for modeling psychopathology, including genomic approaches (Bilder et al. 2004). One of the main thrusts of Berridge’s article is a critical analysis of the role of DA in reinforcement learning, and we particularly appreciate his attempt to differentiate his account from a learning standpoint, for example, by his experiments with serial conditioned stimuli (CSs). We are graciously assigned one of the competing perspectives to Berridge’s “incentive sensitization” hypothesis in terms of our speculations about the role of DA in habit learning. However, our position is a much more general one that in many ways is in harmony with that of Berridge, although on the basis of very different evidence. His discussion of a “motivational” role for the ascending DA system reminds us in many ways of notions that we have entertained in several previous articles (Robbins and Everitt 1982, 1987, 1992, 1995; Robbins et al. 1989). Thus, we suggested that functions of the central DA systems could be explained in terms of an “energetic” construct (i.e., one that accounts for the vigor and frequency of behavioral output) of “activation.” This activational state, which is particularly important in the modulation of behavioral (and cognitive) output, has to be distinguished from concepts of arousal that affect the efficiency of cortical processing. As posited in our 1992 review of the considerable empirical data already then available, activation (sometimes confusingly called “behavioral arousal”) is induced by many related states or stimuli, including food deprivation, “stress,” psychomotor stimulant drugs, aversive stimuli such as tail-pinch and foot-shock, novelty, CSs, including predictors of appetitive events such as food, and also of aversive events (Robbins and Everitt 1992). The range of these stimuli and states, incidentally goes far beyond the hypothesis that the midbrain DA system responds simply to error prediction signals, especially as the class of activating stimuli also includes novel stimuli under certain conditions (c.f. Bardo et al. 1990). However, we acknowledge that there is controversy about the relative sensitivity of the midbrain DA neurons to different states and stimuli—often arising from differences in the methods for indexing such changes, for example, electrophysiological, which are more sensitive to phasic Psychopharmacology (2007) 191:433–437 DOI 10.1007/s00213-006-0528-7

Selective disruption of displacement behaviour by lesions of the mesolimbic dopamine system

Abstract: In the wild, organisms generally allocate their time among many behavioural tendencies in response to both current and anticipated motivational requirements. However, activities that are apparently 'irrelevant' often intrude, either during conflict between these behavioural tendencies, or when a strong tendency is thwarted. These 'irrelevant' activities are called displacement behaviours and are widely documented in the ethological literature. We report here that an experimental analogue of displacement behaviour in the rat depends upon the integrity of the mesolimbic dopaminergic projection to the nucleus accumbens septi, olfactory tubercle and associated structures of the forebrain.

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.