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.

Decision-making cognition in mania and depression.

Abstract: Background. Despite markedly different clinical presentations, few studies have reported differences in neuropsychological functioning between mania and depression. Recent work has suggested that differences may emerge on cognitive tasks requiring affective processing, such as decision-making. The present study sought to compare decision-making cognition in mania and depression in order to clarify the current profiles of impairment for these disorders and to contribute to our more general understanding of the relationship between mood and cognition.Methods. Medicated manic patients, depressed patients, and normal healthy controls completed a computerized decision-making task. All subjects were asked to win as many points as possible by choosing outcomes based on variably-weighted probabilities and by placing ‘bets’ on each decision.Results. Both patient groups were impaired on this task, as evidenced by slower deliberation times, a failure to accumulate as many points as controls and suboptimal betting strategies. Manic, but not depressed, patients made suboptimal decisions – an impairment that correlated with the severity of their illness.Conclusions. These findings are consistent with a growing consensus that manic and depressed patients are characterized by significant impairments in cognitive and particularly executive, functioning. Furthermore, the distinct patterns of observed impairment in manic and depressed patients suggests that the nature and extent of cognitive impairment differ between these two groups. Viewed in the context of other recent studies, these findings are consistent with a role for the ventromedial prefrontal cortex in mediating mood–cognition relationships.

An observational method for quantifying the behavioural effects of dopamine agonists: contrasting effects of d-amphetamine and apomorphine.

Abstract: A novel means of measuring and analysing behavioural effects of dopamine agonists is described and illustrated by a comparison of the effects of d-amphetamine and apomorphine in the rat. d-Amphetamine (0–15 mg/kg IP) produced significant dose- and time-dependent changes in responses such as locomotion, rearing and sniffing, but not in licking or gnawing. In contrast, apomorphine (0–5 mg/kg SC) produced significant increases in licking and gnawing, as well as in locomotion and sniffing, but no changes in rearing. The results are discussed in comparison with those obtained by other methods, such as photocell beam interruptions or stereotypy rating scales, and may be of importance in elucidating the functions of the forebrain dopamine projections.

Dissociating executive mechanisms of task control following frontal lobe damage and Parkinson's disease

Abstract: Twelve patients with focal damage of the frontal cortex and 12 patients with mild, medicated, early stage Parkinson's disease switched between letter- and digit=naming tasks on every second trial of a task-switching paradigm. Compared with age- and IQ-matched control performance, patients with left-sided, but not right-sided, frontal damage exhibited markedly increased time costs associated with these predictable switches only when there was a general incidence of interference or 'crosstalk' between the tasks, and particularly so when the available task cues were relatively weak and arbitrary. The same patients also showed evidence of an increased sensitivity to the facilitatory and inhibitory effects of previous processing, when required to switch between tasks. Both groups of patients (with left- or right-sided frontal damage) exhibited slow, disorganized performance early in practice. In contrast to these frontal effects, the Parkinson's disease patients showed little indication of larger time costs of task switches but they did show progressive increases in the error costs, while age- and IQ-matched control subjects showed reductions. We propose that while both left and right frontal cortical areas are involved in the organization of cognitive and motor processes in situations involving novel task demands, only the left frontal cortex is involved in the dynamic reconfiguring between already-established task-sets, and specifically, that it is the site of an executive mechanism responsible for the modulation of exogenous task-set activity. Finally, dopaminergic transmission, along the nigrostriatal pathway, may be implicated in sustaining various cognitive and motor processes over prolonged periods, including the operation of those executive control mechanisms that accomplish reconfiguring between task-sets.

Double dissociations of memory and executive functions in working memory tasks following frontal lobe excisions, temporal lobe excisions or amygdalo-hippocampectomy in man

Abstract: Thirty-two neurosurgical patients with unilateral or bilateral frontal lobe excisions, 41 patients with unilateral temporal lobe lesions and 19 patients who had undergone unilateral amygdalo-hippocampectomy were compared with matched controls on a computerized test of spatial working memory. A significant deficit was observed in the frontal lobe group, even at the least challenging level of task difficulty and this impairment was found to relate to the inefficient use of a particular searching strategy shown to improve performance on this task. In contrast, deficits in the temporal lobe group and the amygdalo-hippocampectomy group were only observed at the most difficult level of the task and in neither group could the deficit be related to the inefficient use of any particular searching strategy. In a follow-up study, the three patient groups were compared on analogous computerized tests of visual and verbal working memory. No deficits were observed in the frontal lobe group. By comparison, both the temporal lobe patients and the amygdalo-hippocampectomy group were significantly impaired in the visual working memory condition but not in the verbal working memory condition. These deficits were clearly evident at all levels of task difficulty and were not related to any particular searching strategy. The data are discussed in terms of the relative contributions of "executive' and "mnemonic' mechanisms to the contrasting, material dependent deficits observed in the frontal and temporal lobe groups.

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.