Baysal, Veli | Özer, Mahmut | Yılmaz, Ergin

Bildiri | 2017 | 2017 Medical Technologies National Conference, TIPTEKNO 20172017-January , pp.1 - 4

In this paper, the effects of autapse (a kind of synapse formed between the axon or soma of a neuron and its own dendrites) on the weak signal detection capacity of a Hodgkin-Huxley (H-H) neuron are investigated. In the study, we consider that the H-H neuron has an inhibitory autapse modeled as a chemical synapse. The subthreshold sine wave is injected to the H-H neuron as a weak signal. Obtained results indicate that inhibitory autapse prominently increases the weak signal detection capacity of a H-H neuron when the proper autaptic time delay and autaptic conductance values are choosen. © 2017 IEEE.

Çalım, Ali | Uzuntarla, Muhammet | Özer, Mahmut

Bildiri | 2014 | 2014 22nd Signal Processing and Communications Applications Conference, SIU 2014 - Proceedings , pp.1991 - 1994

In this study, the information coding issue in the nervous system is investigated. By using mathematical equations for modeling the dynamics of the basic units of the system, which are neurons, the information processing performance of the neuron populations is systematically studied. As most of studies in the literature investigate the subject by considering neuron populations as homogenous systems, in this study, the populations are considered as heterogeneous in terms of neuronal excitability. The obtained results demonstrate that considering the heterogeneity of the populations provides significant advantages for the processing . . .of neuronal information. It is shown that the neuron population exhibits maximal performance (resonance) for two different levels of network heterogeneity. Moreover, the influences of other biological parameters, forming the whole system, on this double-resonance phenomenon are investigated. © 2014 IEEE Daha fazlası Daha az

Çalım, Ali | Ağaoğlu, Şükriye Nihal | Uzuntarla, Muhammet

Bildiri | 2017 | 2017 25th Signal Processing and Communications Applications Conference, SIU 2017 , pp.1991 - 1994

Vital functions which take place in the brain are accomplished through synchronized neural activities between interconnected neuronal populations. In healthy and unhealthy nerve system, rhythms in different frequencies can be recognized as they are responsible for neural synchronization. Despite this, in the case of global synchronization where oscillation power is the maximum, as observed in epileptic seizures, neural activity can terminate. In this study, effects of neural network characteristics synchronization emerges from on activity termination are computationally investigated. Stochastic Hodgkin-Huxley (H-H) equations are use . . .d in the simulations. The results show that synchronization increases when neurons have high synaptic conductance and due to this, strong synaptic current neurons exposed to terminates the firings. © 2017 IEEE Daha fazlası Daha az

Erkaymaz, Okan | Palabaş, Tuğba

Bildiri | 2018 | 26th IEEE Signal Processing and Communications Applications Conference, SIU 2018 , pp.1 - 4

Computer assisted automatic diagnostic systems are used for the purpose of speeding up diagnosis and treatment and helping to make the right decision. In this study, cervical cancer is identified using four basic classifiers: Naive Bayes (NB), k-Nearest Neighbor (kNN), Multilayer Perceptron (MLP) and Decision Trees (KA-C4.5) algorithms and random subspaces ensemble algorithm. Gain Ratio Attribute Evaluation (GRAE) feature extraction algorithm is applied to contribute to classification performance. The classification results obtained with all datasets and reduced datasets are compared with respect to performance criteria such as accu . . .racy, Root Mean Square Error (RMSE), Sensitivity, Specificity performance criteria. According to the obtained performance analysis, it is seen that the classification performance with the random subspace ensemble algorithm using the kNN basic classifier on the reduced data set is the highest (%95.51). © 2018 IEEE Daha fazlası Daha az

Akbuğday, Burak | Yılmaz, Ergin

Bildiri | 2019 | TIPTEKNO 2019 - Tip Teknolojileri Kongresi , pp.1 - 4

Obstructive sleep apnea defined as a medical condition caused by loss of muscle tone in upper airway dilator muscles. There are various treatment methods exist for this condition both invasive and non-invasive, but they all have their weaknesses and strengths. Electrical stimulation method seems to be the most promising non-invasive method in terms of efficiency and adherence rate. This study introduces a low-cost, easy-to-use and wireless novel device to treat obstructive sleep apnea based on electrical stimulation method. The developed device uses an accelerometer to track respiration and apnea episodes and when an apnea episode i . . .s detected delivers a small electric current to dilator muscles to make them regain their muscle tone, thus treating obstructive sleep apnea. The device also communicates with a smartphone application to keep a recording of respiration and apnea data to enable further studying of data by medical professionals and researchers. © 2019 IEEE Daha fazlası Daha az

Baysal, Veli | Yılmaz, Ergin

Makale | 2020 | Physica A: Statistical Mechanics and its Applications537 , pp.1 - 4

In this paper, Vibrational Resonance (VR), in which the response of some dynamical systems to a weak, low frequency signal can be enhanced by the optimal amplitude of high frequency signal, is investigated under the effects of electromagnetic induction in both single neurons and small-world networks. We find that the occurrence of VR in single neurons requires less energy in the presence of electromagnetic induction, although the resonant peak of the response reduces. Besides, VR can be obtained in small-world networks both with and without electromagnetic induction. In small-world neuronal networks, the highest resonance peak of VR . . . enhances with an increase in the probability of adding link in case of without electromagnetic induction. On the other hand, with the increasing of the probability of adding link, VR disappears in the presence of relatively strong electromagnetic induction, while it enhances in the presence of relatively weak electromagnetic induction. © 2019 Elsevier B.V Daha fazlası Daha az

Baysal, Veli | Yılmaz, Ergin | Özer, Mahmut

Bildiri | 2015 | 2016 MEDICAL TECHNOLOGIES NATIONAL CONFERENCE (TIPTEKNO) , pp.1 - 4

In this paper, the effects of autapse (a kind of synapse formed between the axon or soma of a neuron and its own dendrite) on the transmission of weak signal are investigated in scale-free neuronal networks. In the study, we consider that each neuron in the network has an autapse modelled as chemical synapse. Besides, a subthreshold signal are injected to all neurons in the network. When obtained results are analyzed, it is seen that the autaptic conductance has a threshold value. According to this threshold, the effects of autapse on the transmission of weak signal are evaluated within two categories. When conductance of autapse is . . . less than this threshold value, autapses with proper autaptic time delay values slightly increase the transmission of weak signal. When autaptic conductance is bigger than the threshold value, autapses with proper autaptic time deley values prominently block the transmission of weak signal Daha fazlası Daha az

Erkan, Yasemin | Saraç, Zehra | Yılmaz, Ergin

Bildiri | 2018 | 26th IEEE Signal Processing and Communications Applications Conference, SIU 2018 , pp.1 - 4

In this study, the effects of electrically non-excitable astrocyte cell on the weak signal detection capacity of Hodgkin-Huxley neuron are investigated. To do this, by applying a subthreshold weak signal to neuron, we investigate the weak signal detection capacity of the neuron depending on calcium channel noise stemmed from random open-close fluctuations of calcium channels. Obtained results show that astrocyte decreases the weak signal detection capacity of Hodgkin-Huxley neuron. © 2018 IEEE.

Baysal, Veli | Yılmaz, Ergin | Özer, Mahmut

Bildiri | 2017 | 2017 Medical Technologies National Conference, TIPTEKNO 20172017-January , pp.1 - 4

In this paper, the effects of autapse on the first spike latency of the stochastic H-H neuron are examined. In the study, it is considered that H-H neuron has an electrical autapse and by applying a suprathreshold periodic signal to neuron the first spike times has been observed. Obtained results show that the first spike latency of H-H neuron increases prominently in a certain autaptic time delay with the increasing of autaptic conductance. Also, the first spike latency decreases with the increasing of autaptic conductance in a different autaptic time delay interval. In the context of these results, we come to conclusion that the a . . .utapse have played important roles on the control of first spike latency of stochastic H-H neurons. © 2017 IEEE Daha fazlası Daha az

Yılmaz, Ergin | Baysal, Veli | Özer, Mahmut

Bildiri | 2015 | 2015 23rd Signal Processing and Communications Applications Conference, SIU 2015 - Proceedings , pp.1114 - 1117

In this paper, the effects of high-frequency driving on the weak signal detection capacity of Hodgkin-Huxley neuron are investigated. It is seen that the response of Hodgkin-Huxley neuron shows vibrational resonance with respect to the amplitude of high-frequency driving, and the best detection is obtained at an optimal amplitude of high-frequency driving. Besides, the effects of the frequency of high-frequency driving on the vibrational resonance are investigated. We arrived at the result that resonant response of the neuron can also be obtained for different frequencies of high-frequency signal but larger amplitudes are required f . . .or greater frequency of high frequency signal. © 2015 IEEE Daha fazlası Daha az

Palabaş, Tuğba | Gürleyen, Hatice Hilal | Uzuntarla, Muhammet

Bildiri | 2019 | TIPTEKNO 2019 - Tip Teknolojileri Kongresi , pp.1114 - 1117

It is known that activity is terminated abruptly as a result of strong synchronization in bistable neuron populations when there is sufficient current stimulation. The aim of this study is to investigate the effect of ion channel blocking on the phenomenon of spontaneous termination of ongoing activity in the bistable neural network connected by excitatory chemical synapses using stochastic Hodgkin-Huxley (H-H) equations. The obtained results show that significant changes in the dynamics of neurons occur due to the blocking of potassium ion channels at different rates depending on the coupling strength. As the coupling of synaptic i . . .nteraction increases, the synchronization between neurons increases and the activity terminates. Simulation results showed that sodium ion channels are not effective on this phenomenon. © 2019 IEEE Daha fazlası Daha az

Ağaoğlu, Şükrüye Nihal | Çalım, Ali | Özer, Mahmut | Uzuntarla, Muhammet

Bildiri | 2017 | 2016 Medical Technologies National Conference, TIPTEKNO 2016 , pp.1114 - 1117

In this study, vibrational resonance phenomena is investigated for topologies of scale-free network in excitable neural system. Effect of heterogeneity which emerges from weightening synaptic conductivity in neural network on performance of weak signal detection is studied. FitzHugh-Nagumo neuron model with electrical coupling is used as excitable system. In the result of numerical simulations; it is seen that the state of the scale-free network being unweighted or weighted, synaptic conductivity and average connectivity degree play a crucial role for determining performance of information coding of neuron population based on vibrat . . .ional resonance. © 2016 IEEE Daha fazlası Daha az