Distinct neural mechanisms underlie the success, precision, and vividness of episodic memory

A network of brain regions have been linked with episodic memory retrieval, but limited progress has been made in identifying the contributions of distinct parts of the network. Here, we utilized continuous measures of retrieval to dissociate three components of episodic memory: retrieval success, precision, and vividness. In the fMRI scanner, participants encoded objects that varied continuously on three features: color, orientation, and location. Participants' memory was tested by having them recreate the appearance of the object features using a continuous dial, and continuous vividness judgments were recorded. Retrieval success, precision, and vividness were dissociable both behaviorally and neurally: successful versus unsuccessful retrieval was associated with hippocampal activity, retrieval precision scaled with activity in the angular gyrus, and vividness judgments tracked activity in the precuneus. The ability to dissociate these components of episodic memory reveals the benefit afforded by measuring memory on a continuous scale, allowing functional parcellation of the retrieval network.James S McDonnell Foundation Scholar Award, Medical Research Council, Wellcome Trust, Economic and Social Research Counci

MicroRNA expression in lymphocyte development and malignancy

This article is available open access through the publisher’s website. Copyright @ 2008 Macmillan Publishers Limited.No abstract available.The Leukemia Research Fund, the Julian Starmer-Smith Memorial Fund, and the Medical Research Council

Poiseuille geometry shear flow apparatus for small-angle scattering experiments

Published versio

Impact of Radiotherapy, Chemotherapy and Surgery in Multimodal Treatment of Locally Advanced Esophageal Cancer

Objectives: It was the aim of this study to assess our institutional experience with definitive chemoradiation (CRT) versus induction chemotherapy followed by CRT with or without surgery (C-CRT/S) in esophageal cancer. Methods: We retrospectively analyzed 129 institutional patients with locally advanced esophageal cancer who had been treated by either CRT in analogy to the RTOG 8501 trial (n = 78) or C-CRT/S (n = 51). Results: The median, 2-and 5-year overall survival (OS) of the entire collective was 17.6 months, 42 and 24%, respectively, without a significant difference between the CRT and C-CRT/S groups. In C-CRT/S patients, surgery statistically improved the locoregional control (LRC) rates (2-year LRC 73.6 vs. 21.2%; p = 0.003); however, this was translated only into a trend towards improved OS (p = 0.084). The impact of escalated radiation doses (>= 60.0 vs. <60.0 Gy) on LRC was detectable only in T1-3 N0-1 M0 patients of the CRT group (2-year LRC 77.8 vs. 42.3%; p = 0.036). Conclusion: Definitive CRT and a trimodality approach including surgery (C-CRT/S) had a comparable outcome in this unselected patient collective. Surgery and higher radiation doses improve LRC rates in subgroups of patients, respectively, but without effect on OS. Copyright (C) 2012 S. Karger AG, Base

Pressure dependent electronic properties of MgO polymorphs: A first-principles study of Compton profiles and autocorrelation functions

The first-principles periodic linear combination of atomic orbitals method within the framework of density functional theory implemented in the CRYSTAL06 code has been applied to explore effect of pressure on the Compton profiles and autocorrelation functions of MgO. Calculations are performed for the B1, B2, B3, B4, B8_1 and h-MgO polymorphs of MgO to compute lattice constants and bulk moduli. The isothermal enthalpy calculations predict that B4 to B8_1, h-MgO to B8_1, B3 to B2, B4 to B2 and h-MgO to B2 transitions take place at 2, 9, 37, 42 and 64 GPa respectively. The high pressure transitions B8_1 to B2 and B1 to B2 are found to occur at 340 and 410 GPa respectively. The pressure dependent changes are observed largely in the valence electrons Compton profiles whereas core profiles are almost independent of the pressure in all MgO polymorphs. Increase in pressure results in broadening of the valence Compton profiles. The principal maxima in the second derivative of Compton profiles shifts towards high momentum side in all structures. Reorganization of momentum density in the B1 to B2 structural phase transition is seen in the first and second derivatives before and after the transition pressure. Features of the autocorrelation functions shift towards lower r side with increment in pressure.Comment: 19 pages, 8 figures, accepted for publication in Journal of Materials Scienc

Social networks and labour productivity in Europe: An empirical investigation

This paper uses firm-level data recorded in the AMADEUS database to investigate the distribution of labour productivity in different European countries. We find that the upper tail of the empirical productivity distributions follows a decaying power-law, whose exponent $\alpha$ is obtained by a semi-parametric estimation technique recently developed by Clementi et al. (2006). The emergence of "fat tails" in productivity distribution has already been detected in Di Matteo et al. (2005) and explained by means of a model of social network. Here we show that this model is tested on a broader sample of countries having different patterns of social network structure. These different social attitudes, measured using a social capital indicator, reflect in the power-law exponent estimates, verifying in this way the existence of linkages among firms' productivity performance and social network.Comment: LaTeX2e; 18 pages with 3 figures; Journal of Economic Interaction and Coordination, in pres

Eye movements reveal a dissociation between memory encoding and retrieval in adults with autism

People with Autism Spectrum Disorder (ASD) exhibit subtle deficits in recollection, which have been proposed to arise from encoding impairments, though a direct link has yet to be demonstrated. In the current study, we used eye-tracking to obtain trial-specific measures of encoding (eye movement patterns) during incidental (natural viewing) and intentional (strategic) encoding conditions in adults with ASD and typical controls. Using this approach, we tested the degree to which differences in encoding might contribute to recollection impairments, or whether group differences in memory primarily emerge at retrieval. Following encoding of scenes, participants were asked to distinguish between old and similar lure scenes and provide 'remember'/'familiar' responses. Intentional encoding increased eye movements and subsequent recollection in both groups to a similar degree, but the ASD group were impaired overall at the memory task and used recollection less frequently. In controls, eye movements at encoding predicted subsequent correct responses and subsequent recollection on a trial-by-trial basis, as expected. In contrast, despite a similar pattern of eye movements during encoding in the two groups, eye movements did not predict trial-by-trial subsequent memory in ASD. Furthermore, recollection was associated with lower similarity between encoding- and retrieval-related eye movements in the ASD group compared to the control group. The eye-tracking results therefore provide novel evidence for a dissociation between encoding and recollection-based retrieval in ASD.This research was supported by a James S. McDonnell Scholar Award to J.S.S., and an Economic and Social Research Council Award to R.A.C. We would like to thank all the participants who gave their time for this experiment, as well as the Autism Research Centre, Cambridge for helping with participant recruitment and providing access to the eye-tracking equipment used for this study