Simulating Cortical Feedback Modulation as Changes in Excitation and Inhibition in a Cortical Circuit Model.

Cortical feedback pathways are hypothesized to distribute context-dependent signals during flexible behavior. Recent experimental work has attempted to understand the mechanisms by which cortical feedback inputs modulate their target regions. Within the mouse whisker sensorimotor system, cortical feedback stimulation modulates spontaneous activity and sensory responsiveness, leading to enhanced sensory representations. However, the cellular mechanisms underlying these effects are currently unknown. In this study we use a simplified neural circuit model, which includes two recurrent excitatory populations and global inhibition, to simulate cortical modulation. First, we demonstrate how changes in the strengths of excitation and inhibition alter the input-output processing responses of our model. Second, we compare these responses with experimental findings from cortical feedback stimulation. Our analyses predict that enhanced inhibition underlies the changes in spontaneous and sensory evoked activity observed experimentally. More generally, these analyses provide a framework for relating cellular and synaptic properties to emergent circuit function and dynamic modulation

First impressions and perceived roles: Palestinian perceptions on foreign aid

This paper summarizes some results of a wider research on foreign aid that was conducted in the West Bank and Gaza Strip in 2010. It seeks to describe the impressions and feelings of Palestinian aid beneficiaries as well as the roles and functions they attached to foreign aid. To capture and measure local perceptions on Western assistance a series of individual in depth interviews and few focus group interviews were conducted in the Palestinian territories. The interview transcripts were processed by content analysis. As research results show — from the perspective of aid beneficiaries — foreign aid is more related to human dignity than to any economic development. All this implies that frustration with the ongoing Israeli-Palestinian conflict inevitably embraces the donor policies and practices too

Accounting for Memory Bank Contention and Delay in High-Bandwidth Multiprocessors

This paper considers issues of memory performance in shared memory multiprocessors that provide a high-bandwidth network and in which the memory banks are slower than the processors. We are concerned with the effects of memory bank contention, memory bank delay, and the bank expansion factor (the ratio of number of banks to number of processors) on performance, particularly for irregular memory access patterns. This work was motivated by observed discrepancies between predicted and actual performance in a number of irregular algorithms implemented for the cray C90 when the memory contention at a particular location is high. We develop a formal framework for studying memory bank contention and delay, and show several results, both experimental and theoretical. We first show experimentally that our framework is a good predictor of performance on the cray C90 and J90, providing a good accounting of bank contention and delay. Second, we show that it often improves performance to have addi..

Movement and Performance Explain Widespread Cortical Activity in a Visual Detection Task.

Recent studies in mice reveal widespread cortical signals during task performance; however, the various task-related and task-independent processes underlying this activity are incompletely understood. Here, we recorded wide-field neural activity, as revealed by GCaMP6s, from dorsal cortex while simultaneously monitoring orofacial movements, walking, and arousal (pupil diameter) of head-fixed mice performing a Go/NoGo visual detection task and examined the ability of task performance and spontaneous or task-related movements to predict cortical activity. A linear model was able to explain a significant fraction (33-55% of variance) of widefield dorsal cortical activity, with the largest factors being movements (facial, walk, eye), response choice (hit, miss, false alarm), and arousal and indicate that a significant fraction of trial-to-trial variability arises from both spontaneous and task-related changes in state (e.g., movements, arousal). Importantly, secondary motor cortex was highly correlated with lick rate, critical for optimal task performance (high d'), and was the first region to significantly predict the lick response on target trials. These findings suggest that secondary motor cortex is critically involved in the decision and performance of learned movements and indicate that a significant fraction of trial-to-trial variation in cortical activity results from spontaneous and task-related movements and variations in behavioral/arousal state

Um ensaio sobre "O Futuro da Indústria no Brasil: Desindustrialização em Debate"

Como indicado pelo subtítulo, esse livro é estimulado pelo renascimento do debate sobre desindustrialização no Brasil. A questão fundamental é saber se o fracasso do crescimento industrial no Brasil vai levar a uma desaceleração geral da economia e, por outro lado, se um crescimento industrial mais rápido é a chave para o crescimento acelerado. Antes de entrar na discussão do conteúdo do livro, será útil começar com uma breve síntese de nossa visão do desenvolvimento, que é bastante ortodoxa

Mini-DIPS Open Access Arabisch: Diagnostisches Kurzinterview bei psychischen Störungen. Übersetzung des Mini-DIPS Open Access

Das Mini-DIPS Open Access Arabisch ist ein diagnostisches Kurzinterview bei psychischen Störungen und eine Übersetzung des Mini-DIPS Open Access (2. Auflage). Es bietet als Kurzfassung des DIPS Open Access eine schnelle und dennoch zuverlässige diagnostische Beurteilung psychischer Störungen nach DSM-5 und ICD-10. Das Mini-DIPS Open Access Arabisch gibt einen Überblick über die allgemeine Belastung der untersuchten Personen und ermöglicht die Dokumentation wichtiger anamnestischer Informationen für Praxis und Forschung. Neben dem Interviewleitfaden liefert das Kurzinterview zu allen aufgeführten psychischen Störungen ergänzende Informationen und Diagnose-Checklisten, die auf den Kriterien des DSM-5 basieren. Damit kann das Mini-DIPS Open Access Arabisch eingesetzt werden, um diagnostische Informationen für Anträge auf Psychotherapie oder Forschungsfragestellungen zeitökonomisch zu ermitteln. Keywords: Arabisches Diagnostisches Interview; Mini-DIPS; Diagnostik; Psychische Störungen; DSM-5; ICD-1

Mini-DIPS Open Access Arabisch: Diagnostisches Kurzinterview bei psychischen Störungen. Übersetzung des Mini-DIPS Open Access

Das Mini-DIPS Open Access Arabisch ist ein diagnostisches Kurzinterview bei psychischen Störungen und eine Übersetzung des Mini-DIPS Open Access (2. Auflage). Es bietet als Kurzfassung des DIPS Open Access eine schnelle und dennoch zuverlässige diagnostische Beurteilung psychischer Störungen nach DSM-5 und ICD-10. Das Mini-DIPS Open Access Arabisch gibt einen Überblick über die allgemeine Belastung der untersuchten Personen und ermöglicht die Dokumentation wichtiger anamnestischer Informationen für Praxis und Forschung. Neben dem Interviewleitfaden liefert das Kurzinterview zu allen aufgeführten psychischen Störungen ergänzende Informationen und Diagnose-Checklisten, die auf den Kriterien des DSM-5 basieren. Damit kann das Mini-DIPS Open Access Arabisch eingesetzt werden, um diagnostische Informationen für Anträge auf Psychotherapie oder Forschungsfragestellungen zeitökonomisch zu ermitteln. Keywords: Arabisches Diagnostisches Interview; Mini-DIPS; Diagnostik; Psychische Störungen; DSM-5; ICD-1

Highly accelerated simulations of glassy dynamics using GPUs: caveats on limited floating-point precision

Modern graphics processing units (GPUs) provide impressive computing resources, which can be accessed conveniently through the CUDA programming interface. We describe how GPUs can be used to considerably speed up molecular dynamics (MD) simulations for system sizes ranging up to about 1 million particles. Particular emphasis is put on the numerical long-time stability in terms of energy and momentum conservation, and caveats on limited floating-point precision are issued. Strict energy conservation over 10^8 MD steps is obtained by double-single emulation of the floating-point arithmetic in accuracy-critical parts of the algorithm. For the slow dynamics of a supercooled binary Lennard-Jones mixture, we demonstrate that the use of single-floating point precision may result in quantitatively and even physically wrong results. For simulations of a Lennard-Jones fluid, the described implementation shows speedup factors of up to 80 compared to a serial implementation for the CPU, and a single GPU was found to compare with a parallelised MD simulation using 64 distributed cores.Comment: 12 pages, 7 figures, to appear in Comp. Phys. Comm., HALMD package licensed under the GPL, see http://research.colberg.org/projects/halm