Brown University

About: Brown University is a education organization based out in Providence, Rhode Island, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 35778 authors who have published 90896 publications receiving 4471489 citations. The organization is also known as: brown.edu & Brown.

Piezo-Electroreflectance in Ge, GaAs, and Si

Abstract: Piezoelectroreflectance in Ge, Si and GaAs studied for uniaxial stress effects on electronic energy bands

Toward a Rational and Mechanistic Account of Mental Effort.

Abstract: In spite of its familiar phenomenology, the mechanistic basis for mental effort remains poorly understood. Although most researchers agree that mental effort is aversive and stems from limitations in our capacity to exercise cognitive control, it is unclear what gives rise to those limitations and why they result in an experience of control as costly. The presence of these control costs also raises further questions regarding how best to allocate mental effort to minimize those costs and maximize the attendant benefits. This review explores recent advances in computational modeling and empirical research aimed at addressing these questions at the level of psychological process and neural mechanism, examining both the limitations to mental effort exertion and how we manage those limited cognitive resources. We conclude by identifying remaining challenges for theoretical accounts of mental effort as well as possible applications of the available findings to understanding the causes of and potential solutions for apparent failures to exert the mental effort required of us.

A new tool to assess treatment fidelity and evaluation of treatment fidelity across 10 years of health behavior research

Abstract: A. Bellg, B. Borrelli, et al. (2004) previously developed a framework that consisted of strategies to enhance treatment fidelity of health behavior interventions. The present study used this framework to (a) develop a measure of treatment fidelity and (b) use the measure to evaluate treatment fidelity in articles published in 5 journals over 10 years. Three hundred forty-two articles met inclusion criteria; 22% reported strategies to maintain provider skills, 27% reported checking adherence to protocol, 35% reported using a treatment manual, 54% reported using none of these strategies, and 12% reported using all 3 strategies. The mean proportion adherence to treatment fidelity strategies was .55; 15.5% of articles achieved greater than or equal to .80. This tool may be useful for researchers, grant reviewers, and editors planning and evaluating trials.

Two dynamically distinct inhibitory networks in layer 4 of the neocortex

Abstract: Normal operations of the neocortex depend critically on several types of inhibitory interneurons, but the specific function of each type is unknown. One possibility is that interneurons are differentially engaged by patterns of activity that vary in frequency and timing. To explore this, we studied the strength and short-term dynamics of chemical synapses interconnecting local excitatory neurons (regular-spiking, or RS, cells) with two types of inhibitory interneurons: fast-spiking (FS) cells, and low-threshold spiking (LTS) cells of layer 4 in the rat barrel cortex. We also tested two other pathways onto the interneurons: thalamocortical connections and recurrent collaterals from corticothalamic projection neurons of layer 6. The excitatory and inhibitory synapses interconnecting RS cells and FS cells were highly reliable in response to single stimuli and displayed strong short-term depression. In contrast, excitatory and inhibitory synapses interconnecting the RS and LTS cells were less reliable when initially activated. Excitatory synapses from RS cells onto LTS cells showed dramatic short-term facilitation, whereas inhibitory synapses made by LTS cells onto RS cells facilitated modestly or slightly depressed. Thalamocortical inputs strongly excited both RS and FS cells but rarely and only weakly contacted LTS cells. Both types of interneurons were strongly excited by facilitating synapses from axon collaterals of corticothalamic neurons. We conclude that there are two parallel but dynamically distinct systems of synaptic inhibition in layer 4 of neocortex, each defined by its intrinsic spiking properties, the short-term plasticity of its chemical synapses, and (as shown previously) an exclusive set of electrical synapses. Because of their unique dynamic properties, each inhibitory network will be recruited by different temporal patterns of cortical activity.