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Functional Magnetic Resonance Imaging (fMRI) has been valuable to the current understanding of brain function and pre-operative evaluation of patients. In the recent years, the technique has been increasingly applied to the cases when the subject is at rest, also referred to as the resting-state fMRI. Resting-state fMRI measures spontaneous fluctuations in the blood oxygen level-dependent (BOLD) signal...
Glaucoma is the second leading cause of blindness and it has been the topic of massive studies to explore the underlying mechanisms of the disease. Resting-state neuroimaging studies have been widely applied to investigate the functional damage of the brain, but little is known about the alterations of the interhemispheric resting-state functional connectivity (RSFC) in patients with primary open-angle...
A measurement method for the evaluation of the image complexity based on SIFT&K-means algorithm, namely the estimation of the mismatch between the target and the interesting points has been introduced in our previous research. Based on this method, we have made some improvements to calculate the image complexity of images with different memory targets. The improved algorithm SIFT&AIM&K-means...
Blinking has two functions: to moisturize eyes and as a defensive response to the environment and responses caused by the by mental processes. In this paper, we investigate statistical characteristics of blinks and blink rate variability of 11 subjects. The subjects are presented with a reading/memorization session preceded and followed by resting sessions. EEG signals were recorded during these sessions...
Despite their potential for many applications, Brain -- Computer Interfaces (BCI) are still rarely used due to their low reliability and long training. These limitations are partly due to inappropriate training protocols, which includes the feedback provided to the user. While feedback should theoretically be explanatory, motivating and meaningful, current BCI feedback is usually boring, corrective...
Mal de debarquement syndrome (MdDS) is a chronic disorder of imbalance characterized by a feeling of rocking and swaying. The medical treatment for MdDS is still limited. Motivated by our previous pilot study that demonstrates the promising clinical efficacy of repetitive transcranial stimulation (rTMS) in MdDS patients, a novel rTMS paradigm, i.e., 1 Hz stimulation over ipsilateral dorsal lateral...
In this paper, we present a novel approach for functional network connectivity in fMRI resting activity using distance correlation. The proposed method accounts for nonlinear relationships between the resting state networks and can be used for both single subject and group level analyses. We showed that the new strategy improves the capacity of characterization of pathological populations, such as,...
Primary open angle glaucoma (POAG) is a kind of progressive neuropathy with no clear cause. In the present fMRI study, a data-driven approach was employed to map the alteration of regional spontaneous activity in POAG patients by measuring the amplitude of low-frequency fluctuation (ALFF) of the blood oxygen level-dependent (BOLD) signal. Twenty one POAG patients and 22 age and gender matched healthy...
Nausea is a commonly occurring symptom typified by epigastric discomfort with the urge to vomit. To date, the brain circuitry underlying the autonomic nervous system response to nausea has not been fully understood. Functional MRI (fMRI), together with a point process adaptive recursive algorithm for computation of the high-frequency (HF) index of heart rate variability (HRV) was combined to evaluate...
Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) is increasingly used to monitor the brain activity. The interactions between the scanner magnetic field, the patient's body, and the EEG electrodes generate a pulsation artifact called ballistocardiogram (BCG) which is synchronized with the patient's heart beat. The BCG artifact is considered here...
In this paper we present reaction-diffusion based two eye model to develop disparity selective binocular simple cell receptive fields (RFs) in layer IV of cat visual cortex (V1). Pre-eye opening environment is used for development of binocular simple cell RFs. Our model also supports post-eye opening period development of binocular simple cell RFs. Developed binocular simple cells, left and right...
Traditionally, the modeling of sensory neurons has focused on the characterization and/or the learning of input-output relations. Motivated by the view that different neurons impose different partitions on the stimulus space, we propose instead to learn the structure of the stimulus space, as imposed by the cell, by learning a cell specific distance function or kernel. Metaphorically speaking, this...
Convergence insufficiency is a vision dysfunction in which people have difficulties performing visual tasks close to them such as reading. Symptoms include headaches, eye strain, blurred and double vision, and visual fatigue. Four subjects participated in 18 hours of vision rehabilitation consisting of home and laboratory sessions. During a longitudinal study, subjects performed a simple vergence...
A measure known as inspection time (IT) has been shown to account for approximately 25% of the variance in peoples' intellectual abilities, as measured by IQ. Despite this strong relationship, inspection time has had only limited success in expanding our knowledge regarding the nature of intelligence, which can be attributed to a lack of understanding of the neurophysiology underlying IT. In the present...
Despite the enormous complexity of the human mind, fMRI techniques are able to partially observe the state of a brain in action. In this paper we describe an experimental setup for real-time fMRI in a bio-feedback loop. One of the main challenges in the project is to reach a detection speed, accuracy and spatial resolution necessary to attain sufficient bandwidth of communication to close the bio-feedback...
We explore unsupervised, hypothesis-free methods for fMRI analysis in two different types of experiments. First, we employ clustering to identify large-scale functionally homogeneous systems. We formulate a generative mixture model, derive the EM algorithm and apply it to delineate functional systems. We also investigate spectral clustering in application to this problem and demonstrate that both...
The visual and auditory map alignment in the superior colliculus of barn owl is important for its accurate localization in prey behavior. This alignment may be disturbed by the blindness or prism wearing, the juvenile barn owl could adapt its auditory map to this mismatch after several weeks training. It is believed in literature that auditory map with the plasticity shifts in terms of the visual...
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