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.

Impulsive choice induced in rats by lesions of the nucleus accumbens core

Abstract: Impulsive choice is exemplified by choosing a small or poor reward that is available immediately, in preference to a larger but delayed reward. Impulsive choice contributes to drug addiction, attention-deficit/hyperactivity disorder, mania, and personality disorders, but its neuroanatomical basis is unclear. Here, we show that selective lesions of the nucleus accumbens core induce persistent impulsive choice in rats. In contrast, damage to two of its afferents, the anterior cingulate cortex and medial prefrontal cortex, had no effect on this capacity. Thus, dysfunction of the nucleus accumbens core may be a key element in the neuropathology of impulsivity.

The Neuropsychopharmacology of Fronto-Executive Function: Monoaminergic Modulation

Abstract: We review the modulatory effects of the catecholamine neurotransmitters noradrenaline and dopamine on prefrontal cortical function. The effects of pharmacologic manipulations of these systems, sometimes in comparison with the indoleamine serotonin (5-HT), on performance on a variety of tasks that tap working memory, attentional-set formation and shifting, reversal learning, and response inhibition are compared in rodents, nonhuman primates, and humans using, in a behavioral context, several techniques ranging from microiontophoresis and single-cell electrophysiological recording to pharmacologic functional magnetic resonance imaging. Dissociable effects of drugs and neurotoxins affecting these monoamine systems suggest new ways of conceptualizing state-dependent fronto-executive functions, with implications for understanding the molecular genetic basis of mental illness and its treatment.

Evolution of cognitive dysfunction in an incident Parkinson's disease cohort

Abstract: We have previously performed detailed clinical and neuropsychological assessments in a community-based cohort of patients with newly diagnosed parkinsonism, and through analysis of a subcohort with idiopathic Parkinson's disease (PD), we have demonstrated that cognitive dysfunction occurs even at the time of PD diagnosis and is heterogeneous. Longitudinal follow-up of the cohort has now been performed to examine the evolution of cognitive dysfunction within the early years of the disease. One hundred and eighty (79%) eligible patients from the original cohort with parkinsonism were available for re-assessment at between 3 and 5 years from their initial baseline assessments. PD diagnoses were re-validated with repeated application of the UKPDS Brain Bank criteria in order to maximize sensitivity and specificity, following which a diagnosis of idiopathic PD was confirmed in 126 patients. Thirteen out of 126 (10%) had developed dementia at a mean (SD) of 3.5 (0.7) years from diagnosis, corresponding to an annual dementia incidence of 30.0 (16.4-52.9) per 1000 person-years. A further 57% of PD patients showed evidence of cognitive impairment, with frontostriatal deficits being most common amongst the non-demented group. However, the most important clinical predictors of global cognitive decline following correction for age were neuropsychological tasks with a more posterior cortical basis, including semantic fluency and ability to copy an intersecting pentagons figure, as well as a non-tremor dominant motor phenotype at the baseline assessment. This work clarifies the profile of cognitive dysfunction in early PD and demonstrates that the dementing process in this illness is heralded by both postural and gait dysfunction and cognitive deficits with a posterior cortical basis, reflecting probable non-dopaminergic cortical Lewy body pathology. Furthermore, given that these predictors of dementia are readily measurable within just a few minutes in a clinical setting, our work may ultimately have practical implications in terms of guiding prognosis in individual patients.

Impulsive choice induced in rats by lesions of the nucleus accumbens core, but not of anterior cingulate or medial prefrontal cortex

Abstract: Impulsive choice is exemplified by the choice of reward that is small, poor, or ultimately disastrous, but is available immediately, in preference to a larger reward obtainable only after a delay Impulsive choice contributes to neuropsychiatric disorders such as drug addiction as well as attention-deficit/hyperactivity disorder (ADHD), mania, and personality disorders Impulsive choice hypothetically results from dysfunction of limbic corticostriatal circuitry implicated in reinforcement processes, via convergence on the nucleus accumbens In this first study of the neuro- anatomical basis of impulsive choice, we show that lesions of the nucleus accumbens core (AcbC) induce impulsivity by dramatically and persistently impairing rats' ability to choose a delayed reinforcer In contrast, lesions of the ante- rior cingulate cortex (ACC) or medial prefrontal cortex (mPFC) had no effect on this capacity, although mPFC lesions appeared to affect general behavioural timing mechanisms Thus, dysfunction of the AcbC may be a key element in the neuropathology of impulsivity

Choosing between Small, Likely Rewards and Large, Unlikely Rewards Activates Inferior and Orbital Prefrontal Cortex

Abstract: Patients sustaining lesions of the orbital prefrontal cortex (PFC) exhibit marked impairments in the performance of laboratory-based gambling, or risk-taking, tasks, suggesting that this part of the human PFC contributes to decision-making cognition. However, to date, little is known about the particular regions of the orbital cortex that participate in this function. In the present study, eight healthy volunteers were scanned, using H2150 PET technology, while performing a novel computerized risk-taking task. The task involved predicting which of two mutually exclusive outcomes would occur, but critically, the larger reward (and penalty) was associated with choice of the least likely outcome, whereas the smallest reward (and penalty) was associated with choice of the most likely outcome. Resolving these “conflicting” decisions was associated with three distinct foci of regional cerebral blood flow increase within the right inferior and orbital PFC: laterally, in the anterior part of the middle frontal gyrus [Brodmann area 10 (BA 10)], medially, in the orbital gyrus (BA 11), and posteriorly, in the anterior portion of the inferior frontal gyrus (BA 47). By contrast, increases in the degree of conflict inherent in these decisions was associated with only limited changes in activity within orbital PFC and the anterior cingulate cortex. These results suggest that decision making recruits neural activity from multiple regions of the inferior PFC that receive information from a diverse set of cortical and limbic inputs, and that the contribution of the orbitofrontal regions may involve processing changes in reward-related information.

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.