Cognition and Brain Sciences Unit

About: Cognition and Brain Sciences Unit is a facility organization based out in Cambridge, United Kingdom. It is known for research contribution in the topics: Cognition & Semantic memory. The organization has 801 authors who have published 3055 publications receiving 257962 citations.

Predictive, interactive multiple memory systems.

Abstract: Most lesion studies in animals, and neuropsychological and functional neuroimaging studies in humans, have focused on finding dissociations between the functions of different brain regions, for example in relation to different types of memory. While some of these dissociations can be questioned, particularly in the case of neuroimaging data, we start by assuming a "modal model" in which at least three different memory systems are distinguished: an episodic system (which stores associations between items and spatial/temporal contexts, and which is supported primarily by the hippocampus); a semantic system (which extracts combinations of perceptual features that define items, and which is supported primarily by anterior temporal cortex); and modality-specific perceptual systems (which represent the sensory features extracted from a stimulus, and which are supported by higher sensory cortices). In most situations however, behavior is determined by interactions between these systems. These interactions reflect the flow of information in both "forward" and "backward" directions between memory systems, where backward connections transmit predictions about the current item/features based on the current context/item. Importantly, it is the resulting "prediction error"--the difference between these predictions and the forward transmission of sensory evidence--that drives memory encoding and retrieval. We describe how this "predictive interactive multiple memory systems" (PIMMS) framework can be applied to human neuroimaging data acquired during encoding or retrieval phases of the recognition memory paradigm. Our novel emphasis is thus on associations rather than dissociations between activity measured in key brain regions; in particular, we propose that measuring the functional coupling between brain regions will help understand how these memory systems interact to guide behavior.

A Domain-General Cognitive Core Defined in Multimodally Parcellated Human Cortex.

Abstract: Numerous brain imaging studies identified a domain-general or “multiple-demand” (MD) activation pattern accompanying many tasks and may play a core role in cognitive control. Though this finding is well established, the limited spatial localization provided by traditional imaging methods precluded a consensus regarding the precise anatomy, functional differentiation, and connectivity of the MD system. To address these limitations, we used data from 449 subjects from the Human Connectome Project, with the cortex of each individual parcellated using neurobiologically grounded multimodal MRI features. The conjunction of three cognitive contrasts reveals a core of 10 widely distributed MD parcels per hemisphere that are most strongly activated and functionally interconnected, surrounded by a penumbra of 17 additional areas. Outside cerebral cortex, MD activation is most prominent in the caudate and cerebellum. Comparison with canonical resting-state networks shows MD regions concentrated in the fronto-parietal network but also engaging three other networks. MD activations show modest relative task preferences accompanying strong co-recruitment. With distributed anatomical organization, mosaic functional preferences, and strong interconnectivity, we suggest MD regions are well positioned to integrate and assemble the diverse components of cognitive operations. Our precise delineation of MD regions provides a basis for refined analyses of their functions.

Memantine and constraint-induced aphasia therapy in chronic poststroke aphasia.

Abstract: Objective We conducted a randomized, double-blind, placebo-controlled, parallel-group study of both memantine and constraint-induced aphasia therapy (CIAT) on chronic poststroke aphasia followed by an open-label extension phase Methods Patients were randomized to memantine (20mg/day) or placebo alone during 16 weeks, followed by combined drug treatment with CIAT (weeks 16–18), drug treatment alone (weeks 18–20), and washout (weeks 20–24), and finally, an open-label extension phase of memantine (weeks 24–48) After baseline evaluations, clinical assessments were done at two end points (weeks 16 and 18), and at weeks 20, 24, and 48 Outcome measures were changes in the Western Aphasia Battery-Aphasia Quotient and the Communicative Activity Log Results Twenty-eight patients were included, and 27 completed both treatment phases The memantine group showed significantly better improvement on Western Aphasia Battery-Aphasia Quotient compared with the placebo group while the drug was taken (week 16, p = 0002; week 18, p = 00001; week 20, p = 0005) and at the washout assessment (p = 0041) A significant increase in Communicative Activity Log was found in favor of memantine-CIAT relative to placebo-CIAT (week 18, p = 0040) CIAT treatment led to significant improvement in both groups (p = 0001), which was even greater under additional memantine treatment (p = 0038) Beneficial effects of memantine were maintained in the long-term follow-up evaluation, and patients who switched to memantine from placebo experienced a benefit (p = 002) Interpretation Both memantine and CIAT alone improved aphasia severity, but best outcomes were achieved combining memantine with CIAT Beneficial effects of memantine and CIAT persisted on long-term follow-up Ann Neurol 2009;65:577–585