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Multichannel neural recording is one of the most important topics in the field of biomedical engineering. This is because there is a need to considerably reduce large amounts of data without degrading the data quality for easy transfer through wireless transmission. Video compression technology is of considerable importance in the field of signal processing. There are many similarities between multichannel...
Greater understanding of neuromuscular control of limb movements is vital for optimizing the treatment of patients with neuromuscular dysfunction. Locusts provide an opportunity to develop new investigative techniques and gain physiological insight into a related, but simpler and more accessible control system. Imposed movements of a stretch receptor in the locusts hind leg generate reflex responses...
In this study, we have comparatively evaluated the effect of reference inputs in the filtering of Brainstem Auditory Evoked Potentials (BAEP). Trial-to-trial variations in BAEP signal are very important in quantifying dynamical properties of the nervous system and in specifying the group-specific effects in clinical studies. Therefore, we have performed a wavelet network based nonlinear FIR filtering...
Several studies describe evoked EEG potentials elicited when a subject is aware of an erroneous decision either taken by him or by an external interface. This paper try to detect Error-related potentials (ErrP) elicited when a human user want to monitors an external system upon which he has no control whatsoever. To this end we use a Bayesian filter to classify erroneous or correct events. On average...
The diffusion weighted imaging (DWI) technique can be utilized to investigate a variety of diseases. We propose an automated system which assists the diagnosis of metabolic brain diseases clinically. In this study, DWI images are preprocessed and exponential apparent diffusion coefficient (eADC) images are produced. The eADC images are later brain extracted and normalized to a standard brain atlas...
We propose a method for the accurate estimation of Partial Directed Coherence (PDC) from multichannel time series. The method is based on multivariate vector autoregressive (MVAR) model identification performed through the recently proposed Vector Optimal Parameter Search (VOPS) algorithm. Using Monte Carlo simulations generated by different MVAR models, the proposed VOPS algorithm is compared with...
We have shown that click evoked auditory brainstem response (ABR) single sweeps can be efficiently processed using a novelty detection paradigm. In this paradigm, the diagnostic system is self-adjusted to the individual measurement setting using the spontaneous activity. ABRs as a large-scale reflection of a stimulus locked neuronal group synchronization at the brainstem level are detected as novel...
This paper deals with the interpretation of the macroscopic features of epileptic spikes recorded in human hippocampus based on a neural network model of the CA1 subfield. The network consists of principal cells (pyramidal neurons) and local interneurons and uses GABAergic and glutamatergic synapses. For pyramidal cells, this paper introduces a novel two-compartment model that was developed using...
We propose a signal processing tool for evaluating the electroencephalogram (EEG) phase reset due to auditory attention by utilizing an inverse analysis of the instantaneous phase for the very first time. EEGs were acquired through an auditory attention experiments with the highest entropy stimulation paradigm. We examined single sweeps of auditory late response (ALR) with the complex continuous wavelet...
To analyze EEG features of burst-suppression soon after cerebral circulatory arrest, 14 rats subjected to 7 or 9 min of asphyxial cardiac arrest are divided into good and bad outcome groups with balanced number of animals based on 72-h neurological deficit score. Results show that both the amplitude of EEG suppression and the burst frequency are significantly different between two groups while the...
Local field potentials (LFP) represent the dendritic activity of a population of cells near the recording electrode. However, how LFP activity is related to single unit activity, and if it provides any additional information has not been well studied. Previously we have shown that temporal spectral modulation of LFP activity can be used to decode dexterous movements of the hand. Here, we analyze simultaneous...
Developmental brain malformations often cause intractable and in many cases generalized and/or multifocal seizures. Surgical intervention is not possible in these cases as it is difficult to isolate the epileptogenic foci. Scalp EEG signals recorded during such seizures include coupled contributions from different sources. If it was possible to decouple these contributions based on differences in...
Maintenance of a stable blood pressure (BP) requires dynamic balance between the sympathetic and parasympathetic outflow to the cardiovascular effectors including the heart and the vasculature system. Beside a loss of motor and sensory functioning, hemodynamic instability is a common problem among individuals with SCI especially those occurring in the cervical region. Cardiovascular disorders associated...
Unsolved problem of cochlear implant as well as hearing aid fitting, i.e., to determine the threshold of most comfortable loudness level motivated our study. In the present study, we apply a single-sweep processing method which employs a hybrid approach of adaptive frame decomposition and the kernel based novelty detection machine for the detection of auditory habituation in late auditory evoked potentials...
The vagal nerve conveys information from and to many organs. The components of the compound action potentials (CAPs) recorded from the vagal nerve give information about the different fiber types present. In this paper, we show that with the average reference recording method an additional component can be measured. This component is missed when using a tripolar recording method. Recordings were made...
Noninvasive brain stimulation became very popular recently. Electroencephalographic (EEG) responses evoked by transcranial magnetic stimulation (TMS) gain more and more interest for basic neurophysiological research and possibly diagnostic purposes. In addition, the effect of TMS to the attentional processes has been reported in many studies. In this paper, the effect of TMS on auditory attention...
Learning, or more generally, plasticity may be studied using cultured neuronal networks on multi electrode arrays. Many protocols have been proposed to change connectivity in such networks. One of these protocols, proposed by Shahaf and Marom, aimed to change the input-output relationship of a selected connection in a network. Although the results were quite promising, the experiments appeared difficult...
In this work we applied the direct directed transfer function (dDTF) to fMRI simultaneously recorded with EEG. The objective of the current study is to explore the functional brain network formed by the regions involved in blood oxygen level dependent (BOLD) response related to interictal spikes in temporal lobe epilepsy (TLE). Since fMRI response have been often observed in extratemporal regions,...
Schizophrenia (SZ) is the most disabling among the psychiatric disorders and associated with multiple abnormalities in brain structure and neurotransmitter systems. The benefits of a validated, quantitative diagnosis tool are well established. Electrovestibulography (EVestG) can detect and record neural activity of vestibular system and associated pathways by a wavelet based method, named neural event...
We introduce the use of graphical models in the decoding process of brain-computer interface (BCI) visual speller data. The standard decoding implicitly assumes a simple graphical model which does not incorporate overlap and refractory effects of the brain signals. We propose a more realistic graphical model that does incorporate these effects. The decoding that follows from the graphical model involves...
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