Here we show that, using functional magnetic resonance imaging (fMRI) blood-oxygen level dependent (BOLD) responses in human primary auditory cortex, it is possible to reconstruct the sequence of tones that a person has been listening to over time. First, we characterized the tonotopic organization of each subject's auditory cortex by measuring auditory responses to randomized pure tone stimuli and modeling the frequency tuning of each fMRI voxel as a Gaussian in log frequency space. Then, we tested our model by examining its ability to work in reverse.
View Article and Find Full Text PDFThe heat-resistant agglutinin 1 (Hra1) is an integral outer membrane protein found in strains of Escherichia coli that are exceptional colonizers. Hra1 from enteroaggregative E. coli strain 042 is sufficient to confer adherence to human epithelial cells and to cause bacterial autoaggregation.
View Article and Find Full Text PDFHere we describe a method for measuring tonotopic maps and estimating bandwidth for voxels in human primary auditory cortex (PAC) using a modification of the population Receptive Field (pRF) model, developed for retinotopic mapping in visual cortex by Dumoulin and Wandell (2008). The pRF method reliably estimates tonotopic maps in the presence of acoustic scanner noise, and has two advantages over phase-encoding techniques. First, the stimulus design is flexible and need not be a frequency progression, thereby reducing biases due to habituation, expectation, and estimation artifacts, as well as reducing the effects of spatio-temporal BOLD nonlinearities.
View Article and Find Full Text PDFThere is substantial interest in using functional magnetic resonance imaging (fMRI) retinotopic mapping techniques to examine reorganization of the occipital cortex after vision loss in humans and nonhuman primates. However, previous reports suggest that standard phase encoding and the more recent population Receptive Field (pRF) techniques give biased estimates of retinotopic maps near the boundaries of retinal or cortical scotomas. Here we examine the sources of this bias and show how it can be minimized with a simple modification of the pRF method.
View Article and Find Full Text PDFJ Med Imaging Radiat Oncol
December 2012
Introduction: Plan-of-the-day adaptive radiotherapy (ART) that has not been optimally designed may result in inefficient plan sizes. This can lead to unused plans, which may potentially reduce overall conformality. We compared two methods of individualising ART plan sizes for muscle-invasive bladder cancer to determine which provides a more balanced distribution of plan selections.
View Article and Find Full Text PDFThe inferior colliculus (IC) of the big brown bat (Eptesicus fuscus) contains specialized neurons that respond exclusively to highly specific spectrotemporal patterns such as sinusoidally frequency modulated (SFM) signals or directional frequency modulated sweeps (FM). Other specialized cells with I-shaped frequency response areas (FRAs) are tuned to very narrow frequency bands (1-2 kHz) in an amplitude-tolerant manner. In contrast, non-specialized neurons respond to any stimulus with energy in their frequency response area.
View Article and Find Full Text PDFBackground: A study was undertaken to investigate the detection of relapse and survival outcomes in patients with cervical cancer treated with curative intent chemoradiotherapy, and evaluated with a post-therapy (18) F-fluorodeoxyglucose positron emission tomography (FDG-PET) scan.
Methods: Between January 2002 and June 2007, 105 consecutive patients were prospectively enrolled into a registry study designed to assess outcomes of chemoradiotherapy. A FDG-PET scan was performed between 3 and 12 months (median, 4.