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To characterize the brain mapping on reinforcement acupuncture stimulation at ST36 (zusanli), and to discuss the mechanisms of acupuncture to treat diseases. Methods: fMRI was performed on 26 healthy Chinese student volunteers. Sixteen subjects were acupunctured at the acupoint ST36, while 10 others at sham-acupoint (lateral from ST36 about 3cm). The fMRI studies were performed using a gradient echo-EPI...
In the study of biological systems, it is often desirable to study the relationship between two simultaneously recorded signals and investigate whether one signal is causing the other. Correlation between signals can be revealed by spectral analysis techniques such as coherence. While coherence reveals the interaction strength between two signals, it does not provide directional information about...
Learning and memory rely on the strict regulation of communication between neurons in the hippocampus. The mossy fiber (MF) pathway connects the dentate gyrus to the auto-associative CA3 network, and the information it carries is controlled by a feedforward circuit combining disynaptic inhibition with monosynaptic excitation. Analysis of the MF associated circuit using a mapped clock oscillator (MCO)...
A multi-input modeling approach is introduced to quantify hippocampal neural dynamics. It is based on the Volterra modeling approach extended to multiple inputs. The computed Volterra kernels allow quantitative description of hippocampal transformations and define a predictive model that can produce responses to arbitrary input patterns. Electrophysiological data from several CA3 and CA1 cells in...
This paper presents an improvement to the exponential entropy driven-homomorphic unsharp masking (E2D-HUM) algorithm devoted to illumination artifact suppression on magnetic resonance images. E2D-HUM requires a segmentation step to remove dark regions in the foreground whose intensity is comparable with background, because strong edges produce streak artifacts on the tissues. This new version of the...
Diffusion tensor imaging (DTI) tractography is a computationally intensive procedure. The most time consuming operation is the tracking of fibers from every voxel in the scanned volume. Fiber tracking can be accelerated significantly by use of reconfigurable hardware, such as field programmable gate arrays (FPGAs), which can track fibers at very high speed by exploiting the flexibility, parallelism...
In this paper we propose a formal formulation for the estimation of Diffusion Tensors in the space of symmetric positive semidefinite (PSD) tensors. Traditionally, diffusion tensor model estimation has been carried out imposing tensor symmetry without constraints for negative eigenvalues. When diffusion weighted data does not follow the diffusion model, due to noise or signal drop, negative eigenvalues...
Local field potentials (LFPs) have been proposed for use in controlling neural prosthetic devices because they can provide reliable motor and sensory-related information, and can easily be recorded over long periods of time. While studies have shown that directional information about motor movements can be inferred from LFPs, it is not known at what depth these signals should be recorded from in order...
A recursive algorithm is presented to improve the spatial resolution of 3-D Electrical Impedance Tomography (EIT) images in a four-shell realistic head model. In this algorithm, the low spatial resolution image derived from the standardized low resolution electromagnetic tomography algorithm (sLORETA) is chosen to be the initial estimate for the Focal Underdetermined System Solver (FOCUSS), and a...
To investigate the accuracy for quantification of brain total creatine (Cr) concentration using in vivo long echo time (TE) PRESS sequence with an external standard and LCModel. Ten swine and an external standard containing a detectable compounds of known concentration were studied by using 1.5 T GE Signa scanner and the standard head coil; the single-voxel proton magnetic resonance spectroscopy (...
Susceptibility-weighted magnetic resonance imaging is a powerful tool for high resolution imaging of the vasculature, aiding in the diagnosis of many pathologic conditions. The technique is especially beneficial at higher field strengths where traditional sequences that measure cerebral blood volume suffer from severe distortions, rendering them inapplicable at 7 T. However, conventional susceptibility-weighted...
This modeling study investigates the functional role of pacemaker neurons in generating stable rhythms in the pre-Botzinger complex, a subcircuit of the respiratory pattern-generating circuitry in mammals. While the presence of pacemakers within the network is without doubt, the percentage and significance of such pacemakers is still unresolved. Here we revisited earlier network simulations by varying...
Mutual adaptation between man and machine is necessary for the development of more efficient devices that allows easy adaptation. The interaction with intelligent machines involves adaptation processes from both the user and the machine. The human body has the ability to change its body schema to include external tools in it, using this fact we proposed the design of intelligent machines with biofeedback...
We present application of adaptive LMS-based method using two different sub-band filtering techniques for active reduction of 3T-fMRI acoustic noise. Analysis and design of the sub-band filters are discussed based on the characteristics of the noise. Using the fMRI-brain scanner acoustic noise, performance of the methods are analyzed and compared for different number of sub-band filters
Rheoencephalography (REG) is impedance plethysmography applied to the head, and provides an indirect measurement of the pulsatility of the cerebral blood volume. To extend REG as a clinical and research tool, it is necessary to evaluate the sensitivity of REG measurement to local brain conductivity changes. By means of the analytical solution of a four-sphere geometrical model of the head, maps of...
We present an architecture of an epileptic seizure prediction system suitable for an implantable implementation. The microsystem comprises a neural interface, a spectral analysis processor and an artificial neural network (ANN). The neural interface and the spectral analysis processor have been prototyped in a 0.35 mum CMOS technology with experimental results are presented. The wavelet-based artificial...
A newly developed system for deep brain hyperthermia able to provide also passive measurements of temperature distributions inside the human body and especially the brain, is presented in this paper. The proposed system able to comprise both therapeutic and diagnostic modules operates in a totally non-invasive contactless way based on the use of an ellipsoidal conductive wall cavity to achieve beamforming...
Detection of unruptured aneurysms is a major task in magnetic resonance angiography (MRA). However, it is difficult for radiologists to detect small aneurysms on the maximum intensity projection (MIP) images because adjacent vessels may overlap with the aneurysms. Therefore, we proposed a method for making a new MIP image, the SelMIP image, with the interested vessels only, as opposed to all vessels,...
Diffuse optical tomography (DOT) is an emerging non-invasive technique for detecting the presence of a tumor or other anomalies from a scattered photon field. In this paper, we derive an alternating projection algorithm to reconstruct the spatially varying absorption coefficient of human brain tissue to detect the presence of tumor. We use a perturbation method and assume the absorption coefficient...
In diffusion tensor MRI (DT-MRI), each voxel is assigned a tensor that describes local water diffusion. In this study, a simulated DT dataset for analyzing the diffusion characteristics is developed to verify and validate DT images postprocessed with various DT analyzing codes. This module is intended as a resource for DT-MRI analyzing tools to verify and validate the analysis results. The b factor...
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