پديد آورنده :
قسامي، سارا
عنوان :
تحريك جمعي نورون ها تحت اثر نوفه
مقطع تحصيلي :
كارشناسي ارشد
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده فيزيك
صفحه شمار :
ده، 54ص.: مصور، جدول، نمودار
يادداشت :
ص.ع. به فارسي و انگليسي
استاد راهنما :
فرهاد شهبازي
استاد مشاور :
كيوان آقابابايي ساماني
توصيفگر ها :
هم گام سازي , حالت برانگيخته , نوسان
تاريخ نمايه سازي :
11/9/91
استاد داور :
مجتبي اعلايي، پيمان صاحب سرا
تاريخ ورود اطلاعات :
1396/09/21
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي
چكيده انگليسي :
Collective Firing Induced by Noise in an Excitable Media in Small World and Random Network Sara Ghassami s ghassami@ph iut ac ir Date of Submission Department of Physics Isfahan University of Technology Isfahan Iran Degree M Sc Language FarsiSupervisor Dr Farhad Shahbazi shahbazi@cc iut ac ir AbstractSynchrony is significant in brain neural network Changes in synchrony can lead to cognitivedysfunctions in neural system Synchronization is defined as an adjustment of rhythms of oscillatingobjects due to their weak interaction An example of these phenamenon is the oscillating of fireflies observation of firing in human neural network and synchrony in a collection of clocks There are threecomplex networks and these are called regular small world and random networks Small world is one ofthe complex networks which is created by rewiring of the edges of a regular network with probability Pand it is used to model neural If the nodes of a network are selected randomly we can get a small worldone Two characteristics of small world networks is short path length and large clustering coefficient Thedegree distribution of the complex network is determined according to the type of the network and how itis constructed Brain pathological state depend on the number of nodes Deleting any node in alzheimerdieases is associated with increased path length or reduced global efficiency There is a direct connectionbetween cognitive dysfunction and changes in neural synchrony In this situation $ rho$ which is calledan order parameter is decreased Various methods are used to model brain with graghs First approach isfunctional connectivity in which EEG MEG and fMRI are used to connect edges and second one isstructural connectivity For example anatomical tract tracing of a brain is a usefull tool to map structuralconnectivity The first approach lead to the undirected gragh and used to model a network The model inwhich we apply to compute some statistical parameters is called Kuramoto and is defined as a coupleddynamical phase oscillators To compute the phase of the oscillators an Ewler method is usefull Noise isa signal that varies as a function of time the value of which at any time is drawn randomly from somedistribution Guassian white noise can increases neural firing rate and is effective in a production of aneural firing pulses The correlation of the noise is a delta function By calculating kuramoto order parameter and current we can see collective firing induced by noise Three dynamical regimes arise no firing in which all of elements confined near the fixed point thesecond regime is a synchronized firing or coherent pulsation where a macroscopic fraction firesimultanously the third one is desynchronized firing or incoherent pulsation By calculating an orderparameter we see that this parameter has a value less than one which means that this parameter dependon an initial condition and a complete synchronization is observed with fixed initial condition Keywords Synchronization Firing Noise Excitable Media Oscillatory
استاد راهنما :
فرهاد شهبازي
استاد مشاور :
كيوان آقابابايي ساماني
استاد داور :
مجتبي اعلايي، پيمان صاحب سرا
