Role of semantic paradigms for optimization of language mapping in clinical FMRI studies.

BACKGROUND AND PURPOSE: The optimal paradigm choice for language mapping in clinical fMRI studies is challenging due to the variability in activation among different paradigms, the contribution to activation of cognitive processes other than language, and the difficulties in monitoring patient performance. In this study, we compared language localization and lateralization between 2 commonly used clinical language paradigms and 3 newly designed dual-choice semantic paradigms to define a streamlined and adequate language-mapping protocol. MATERIALS AND METHODS: Twelve healthy volunteers performed 5 language paradigms: Silent Word Generation, Sentence Completion, Visual Antonym Pair, Auditory Antonym Pair, and Noun-Verb Association. Group analysis was performed to assess statistically significant differences in fMRI percentage signal change and lateralization index among these paradigms in 5 ROIs: inferior frontal gyrus, superior frontal gyrus, middle frontal gyrus for expressive language activation, middle temporal gyrus, and superior temporal gyrus for receptive language activation. RESULTS: In the expressive ROIs, Silent Word Generation was the most robust and best lateralizing paradigm (greater percentage signal change and lateralization index than semantic paradigms at P P P P CONCLUSIONS: The combination of Silent Word Generation and ≥1 visual semantic paradigm, such as Sentence Completion and Noun-Verb Association, is adequate to determine language localization and lateralization; Noun-Verb Association has the additional advantage of objective monitoring of patient performance

Ultrafast Energy Transfer in an Artificial Photosynthetic Antenna

We temporally resolved energy transfer kinetics in an artificial light- harvesting dyad composed of a phthalocyanine covalently linked to a carotenoid. Upon carotenoid photo-excitation, energy transfers within ≈100fs (≈52% efficiency) to the phthalocyanine

Non-contrast MR imaging of blood-brain barrier permeability to water

Neuro Imaging Researc

Measurement of arteriolar blood volume in brain tumors using MRI without exogenous contrast agent administration at 7T

Neuro Imaging Researc

Resolving Energy and Electron Transfer Processes in Dyads With the Help of Global and Target Analysis

In any photosynthetic/photocatalytic device, multiple steps are required between the arrival of a solar photon and the formation of a stable product. Here we explain and demonstrate the target analysis methodology to develop minimal models, identify the steps and estimate the parameters that characterize energy converting devices. With this modelling tool the molecular mechanisms of the loss processes can be identified and quantified. This can then inspire photosynthetic device optimization by precisely targeting those sites involved in the most significant losses. Two case studies of recently published measurements (Pillai et al., 2013) on a carotenoporphyrin dyad and a carotenofullerene dyad are modelled in depth. After carotenoid excitation, no excited state energy transfer (EET) to porphyrin was found, but EET from carotenoid hot S1 to the fullerene moiety occurred with a rate of 1.6/ps. The total radical pair yields of these dyads were found to be, respectively, 46% and 79%. Out of these 79%, 31% were due to electron transfer from the fullerene excited state. The triplet yields were 3.8% and 4.6%. The remainder of the excitations decay to the ground state from the carotenoid hot S-1 and S-1 states

Power and sample size calculations for multivariate linear models with random explanatory variables

MANCOVA, MANOVA, multivariate regression, noncentral F distribution.,