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While brain computer interface (BCI) can be employed with patients and healthy subjects there are problems that must be resolved before BCI can be useful to the public. In the mos popular motor imagery (MI) BCI system, a significant number of target users (called "BCI Illiterates") cannot modulate their neuronal signals sufficiently to use the BCI system. Thi causes performance variability among subjects and even among sessions within a subject The mechanism of such BCI-Illiteracy and possible solutions still remain to be determined Gamma oscillation is known to be involved in various fundamental brain functions, and ma play a role in MI. In this study, we investigated the association of gamma activity with M performance among subjects. Ten simultaneous MEG/EEG experiments were conducted MI performance for each was estimated by EEG data, and the gamma activity associate with BCI performance was investigated with MEG data. Our results showed that gamm activity had a high positive correlation with MI performance in the prefrontal area. Thi trend was also found across sessions within one subject. In conclusion, gamma rhythm generated in the prefrontal area appear to play a critical role in BCI performance. [ABSTRACT FROM AUTHOR]

The image reconstruction problem for fully 3D TOF PET is challenging because of the large data sizes involved. One approach to this problem is to first rebin the data into one of the following lower dimensional formats: 2D TOF, 3D non TOF or 2D non TOF. Here we present a unified framework based on a generalized projection slice theorem for TOF data that can be used to compute each of these mappings. We use this framework to develop approaches for rebinning into non TOF formats without significant loss of information. We first derive the exact mappings and then describe approximations which address the missing data problem for oblique sinograms. We evaluate the performance of approximate rebinning using Monte Carlo simulations. Our results show that rebinning into non TOF sinograms retains significant SNR advantages over sinograms collected without TOF information. [ABSTRACT FROM AUTHOR]

We mapped regulatory loci for nearly all protein-coding genes in mammals using comparative genomic hybridization and expression array measurements from a panel of mouse–hamster radiation hybrid cell lines. The large number of breaks in the mouse chromosomes and the dense genotyping of the panel allowed extremely sharp mapping of loci. As the regulatory loci result from extra gene dosage, we call them copy number expression quantitative trait loci, or ceQTLs. The −2log10P support interval for the ceQTLs was <150 kb, containing an average of <2–3 genes. We identified 29,769 trans ceQTLs with −log10P > 4, including 13 hotspots each regulating >100 genes in trans. Further, this work identifies 2,761 trans ceQTLs harboring no known genes, and provides evidence for a mode of gene expression autoregulation specific to the X chromosome. [ABSTRACT FROM AUTHOR]

Ordered subset expectation maximization (OSEM) is the most widely used algorithm for clinical PET image reconstruction. OSEM is usually stopped early and post-filtered to control image noise and does not necessarily achieve optimal quantitation accuracy. As an alternative to OSEM, we have recently implemented a penalized likelihood (PL) image reconstruction algorithm for clinical PET using the relative difference penalty with the aim of improving quantitation accuracy without compromising visual image quality. Preliminary clinical studies have demonstrated visual image quality including lesion conspicuity in images reconstructed by the PL algorithm is better than or at least as good as that in OSEM images. In this paper we evaluate lesion quantitation accuracy of the PL algorithm with the relative difference penalty compared to OSEM by using various data sets including phantom data acquired with an anthropomorphic torso phantom, an extended oval phantom and the NEMA image quality phantom; clinical data; and hybrid clinical data generated by adding simulated lesion data to clinical data. We focus on mean standardized uptake values and compare them for PL and OSEM using both time-of-flight (TOF) and non-TOF data. The results demonstrate improvements of PL in lesion quantitation accuracy compared to OSEM with a particular improvement in cold background regions such as lungs. [ABSTRACT FROM AUTHOR]

A correction to the article "Fine mapping of regulatory loci for mammalian gene expression using radiation hybrids" that was published online on March 23, 2008 is presented.