Search for: local-field-potential
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    Neural Synchrony of Spiking Local Neurons and Local Field Potential Activities in Primary Visual Cortex of Awake Monkeys

    , M.Sc. Thesis Sharif University of Technology Masoudian, Saeed (Author) ; Jafari, Mehdi (Supervisor) ; Rabiee, Hamid Reza (Supervisor) ; Lashgari, Reza (Co-Supervisor)
    Primary visual cortex plays a paramount role in processing visual information. Visual information after the primitive processing by LGN and Thalamus, will be sent to the primary visual cortex which is called V1 area. According to the fact that V1 neurons have the definitive sensitivity to the edge and contrast of visual stimuli so their behavior are very selective to the certain features, specially contrast, of visual stimuli. These neurons have different response behavior to contrast. In fact most of them have some nonlinear behavior to this feature. Normally we expect that response of them or spiking rate of them grow linearly by the contrast increases but in most many cases they have some... 

    The olfactory bulb modulates entorhinal cortex oscillations during spatial working memory

    , Article Journal of Physiological Sciences ; Volume 71, Issue 1 , 2021 ; 18806546 (ISSN) Salimi, M ; Tabasi, F ; Nazari, M ; Ghazvineh, S ; Salimi, A ; Jamaati, H ; Raoufy, M. R ; Sharif University of Technology
    BioMed Central Ltd  2021
    Cognitive functions such as working memory require integrated activity among different brain regions. Notably, entorhinal cortex (EC) activity is associated with the successful working memory task. Olfactory bulb (OB) oscillations are known as rhythms that modulate rhythmic activity in widespread brain regions during cognitive tasks. Since the OB is structurally connected to the EC, we hypothesized that OB could modulate EC activity during working memory performance. Herein, we explored OB–EC functional connectivity during spatial working memory performance by simultaneous recording local field potentials when rats performed a Y-maze task. Our results showed that the coherence of delta,... 

    Introducing a comprehensive framework to measure spike-LFP coupling

    , Article Frontiers in Computational Neuroscience ; Volume 12 , 2018 ; 16625188 (ISSN) Zarei, M ; Jahed, M ; Daliri, M. R ; Sharif University of Technology
    Frontiers Media S.A  2018
    Measuring the coupling of single neuron's spiking activities to the local field potentials (LFPs) is a method to investigate neuronal synchronization. The most important synchronization measures are phase locking value (PLV), spike field coherence (SFC), pairwise phase consistency (PPC), and spike-triggered correlation matrix synchronization (SCMS). Synchronization is generally quantified using the PLV and SFC. PLV and SFC methods are either biased on the spike rates or the number of trials. To resolve these problems the PPC measure has been introduced. However, there are some shortcomings associated with the PPC measure which is unbiased only for very high spike rates. However evaluating... 

    Stimulus-specific adaptation decreases the coupling of spikes to LFP phase

    , Article Frontiers in Neural Circuits ; Volume 13 , 2019 ; 16625110 (ISSN) Parto Dezfouli, M ; Zarei, M ; Jahed, M ; Daliri, M. R ; Sharif University of Technology
    Frontiers Media S.A  2019
    Stimulus repetition suppresses the neural activity in different sensory areas of the brain. This mechanism of so-called stimulus-specific adaptation (SSA) has been observed in both spiking activity and local field potential (LFP) responses. However, much remains to be known about the effect of SSA on the spike–LFP relation. In this study, we approached this issue by investigating the spike-phase coupling (SPC) in control and adapting paradigms. For the control paradigm, pure tones were presented in a random unbiased sequence. In the adapting paradigm, the same stimuli were presented in a random pattern but it was biased to an adapter stimulus. In fact, the adapter occupied 80% of the... 

    Online analysis of local field potentials for seizure detection in freely moving rats

    , Article Iranian Journal of Basic Medical Sciences ; Volume 23, Issue 2 , 2020 , Pages 173-177 Zare, M ; Nazari, M ; Shojaei, A ; Raoufy, M. R ; Mirnajafi Zadeh, J ; Sharif University of Technology
    Mashhad University of Medical Sciences  2020
    Objective(s): Seizure detection during online recording of electrophysiological parameters is very important in epileptic patients. In the present study, online analysis of field potential recordings was used for detecting spontaneous seizures in epileptic animals. Materials and Methods: Epilepsy was induced in rats by pilocarpine injection. During the chronic period of the pilocarpine model, local field potential (LFP) recording was run for at least 24 hr. At the same time, video monitoring of the animals was done to determine the real time of seizure occurrence. Both power and sample entropy of LFP were used for online analysis. Results: Obtained results showed that changes in LFP power... 

    Introducing a Comprehensive Framework to Measure Spike-LFP Coupling

    , Ph.D. Dissertation Sharif University of Technology Zarei, Mohammad (Author) ; Jahed, Mehran (Supervisor) ; Daliri, Mohammad Reza (Co-Supervisor)
    LFP characteristics have been shown to be informative of sensory stimuli and influenced by attention. We show the gamma power in area MT is selective to motion direction showing a Gaussian tuning curve. Here we show for the first time, some evidence based on a single monkey’s data that spatial attention enhances the tuning curve based on gamma power.The synchronization of activity across neurons has been a focus in many recent studies of information processing in networks of cortical cells and areas. One aspect of such inter-neuronal synchrony is the locking of spiking activity to local field potentials (LFPs). Such an interaction has been observed between the timing of individual action... 

    Multifractal detrended fluctuation analysis of continuous neural time series in primate visual cortex

    , Article Journal of Neuroscience Methods ; Volume 312 , 2019 , Pages 84-92 ; 01650270 (ISSN) Fayyaz, Z ; Bahadorian, M ; Doostmohammadi, J ; Davoodnia, V ; Khodadadian, S ; Lashgari, R ; Sharif University of Technology
    Elsevier B.V  2019
    Background: Local field potential (LFP) recordings have become an important tool to study the activity of populations of neurons. The functional activity of LFPs is usually compared with the activity of neighboring single spike neurons with sampling rates much higher than those of the continuous field potential channel (5 kHz). However, comparison of these signals generated with the lower sampling rate technique is important. New method: In this study, we provide an analysis of extracellular field potential time series using the sophisticated nonlinear multifractal detrended fluctuation analysis (MF-DFA). Using the MF-DFA, we demonstrate that the integral of the singularity spectrum is a... 

    Processing the Local Field Potential Signals in Comparison to Neighboring Simple and Complex Neurons of Primary Visual Cortex

    , M.Sc. Thesis Sharif University of Technology Eftekhar, Morteza (Author) ; Lashgari, Reza (Supervisor)
    In neural systems of living organism, moreover than differences in anatomic structure of cells, there is also differences in physiological functions of analogous cells.Specification and categorization of neurons based on physiological functions is one of objectives of neuroscience. Study of cognitive behaviors and systematic study of neural system, modeling and practical applications in neural prosthesis design are some of applications of categorizing neural cells. Neural signals can be studied by Spike rate of a single neuron activity or Local Field Potential (LFP) of a finite number of neurons. In previous studies neurons of first visual cortex are divided into two groups of simple and... 

    Collective behavior of interacting locally synchronized oscillations in neuronal networks

    , Article Communications in Nonlinear Science and Numerical Simulation ; Volume 17, Issue 10 , 2012 , Pages 3922-3933 ; 10075704 (ISSN) Jalili, M ; Sharif University of Technology
    Elsevier  2012
    Local circuits in the cortex and hippocampus are endowed with resonant, oscillatory firing properties which underlie oscillations in various frequency ranges (e.g. gamma range) frequently observed in the local field potentials, and in electroencephalography. Synchronized oscillations are thought to play important roles in information binding in the brain. This paper addresses the collective behavior of interacting locally synchronized oscillations in realistic neural networks. A network of five neurons is proposed in order to produce locally synchronized oscillations. The neuron models are Hindmarsh-Rose type with electrical and/or chemical couplings. We construct large-scale models using... 

    Allergic rhinitis impairs working memory in association with drop of hippocampal – Prefrontal coupling

    , Article Brain Research ; Volume 1758 , 2021 ; 00068993 (ISSN) Salimi, M ; Ghazvineh, S ; Nazari, M ; Dehdar, K ; Garousi, M ; Zare, M ; Tabasi, F ; Jamaati, H ; Salimi, A ; Barkley, V ; Mirnajafi Zadeh, J ; Raoufy, M. R ; Sharif University of Technology
    Elsevier B.V  2021
    Allergic rhinitis (AR) is a chronic inflammatory disease frequently associated with a deficit in learning and memory. Working memory is an important system for decision making and guidance, which depends on interactions between the ventral hippocampus (vHipp) and the prelimbic prefrontal cortex (plPFC). It is still unclear whether AR influences the activity and coupling of these brain areas, which consequently may impair working memory. The current study aimed to examine alterations of the vHipp-plPFC circuit in a rat model of AR. Our results show decreased working memory performance in AR animals, accompanied by a reduction of theta and gamma oscillations in plPFC. Also, AR reduces...