A sample program of the phase converter model
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Created Date: Mar 16, 2011 13:59:26

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Free Keywords: adaptive filter, granular layer, phase converter model
ID  39  
Title  A sample program of the phase converter model  
Free Keywords  adaptive filter, granular layer, phase converter model  
Description  This is an implementation of the phase converter model proposed by Fujita (1982). Specifically, the granular layer, the phase leadlag generator of granule cell activity, is implemented. This is our implementation of the cerebellar model presented in the following paper: M. Fujita (1982). Adaptive filter model of the cerebellum. Biological Cybernetics. Vol.45, pp.195206. This implementation is independent of the original version developed by Fujita (1982). * About the model ** Model description without Laplace transform Let u(t) be the mossy fiber signal at time t. x_{i}(t), the activity of granule cell i at time t, is calculated as x_{i}(t) = [ w_{i} u(t)  y(t) ]+, where [x]+ = x if x > 0 and 0 otherwise, w_{i} is the weight of mossy fiber synapses at the granule cell, and y(t) is the activity of the Golgi cell at time t. Notice that only one Golgi cell is incorpoated in the model. The Golgi cell is a leaky integrator: y(t) is calculated as y(t) = \int_{0}^{t} \exp((ts)/\tau) (w_{pf}\sum_{i}x_{i}(s) + u(s)) ds, where \tau is the integration constant and w_{pf} is the parallelfiber synaptic weight. ** How does the model work? For simplicity, let's consider the case of sinusoidally oscillating mossy fiber signals: u(t) = sin(2pi f t), where f is the oscillation frequency. Also, let's consider the case that the Golgi cell receives inputs only from mossy fibers, namely, w_{pf} = 0. Then, because the Golgi cell is an integrator, if \tau is large enough, the output of the cell becomes y(t) = c cos(2pi f t), where c is constant. Now, the activity of granule cell i is given x_{i}(t) = [ w_{i} sin(2pi f t)  c cos(2pi f t) ]+ = [ sin(2pi f t  phi_{i}) ]+, where phi_{i} = atan(c/w_{i}). Therefore, granule cells become active sinusoidally with various phases. Notice that the phase variation is generated through the variation of mossy fiber synaptic weights across cells. Next, let's consider the case of w_{pf} > 0. If granule cells become active one by one sequentially, the parallelfiber input signals to the Golgi cell may become almost constant. Thus, the Golgi cell inhibit granule cells tonically, which controls the threshold of granule cells' activity, as argued by Marr (1969) and Albus (1971). * Files This folder contains the following files: readme.txt :: This file Makefile :: Makefile adaptive_filter.c :: The source code written in C. gr.dat :: responses of granule cells to sinusoidal MF signals go.dat :: response of a Golgi cell to sinusoidal MF signals mf.dat :: MF signals plot.gp :: The script to plot gr.dat, go.dat, mf dat using gnuplot * Usage Parameters can be set at the head of the program. % make % ./adaptive_filter mf.dat, gr.dat, go.dat are generated % gnuplot plot.gp (if you have gnuplot) mf.dat, gr.dat and go.dat are plotted. * Authors Takeru Honda and Tadashi Yamazaki TH: Dept. of Information and Communication Engineering, University of Electrocommunications. TY: Lab. for Motor Learning Control, RIKEN Brain Science Institute. * Copyright Copyright (c) 2007 RIKEN (The Institute of Physical and Chemical Research) Some rights reversed. * License CCBY This work is licensed under the Creative Commons Attribution 3.0 License. To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0/ or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA. 

Last Modified Date  Mar 21, 2013 13:58:47  
Created Date  Mar 16, 2011 13:59:26  
Contributor  NIJC Administrator (nijcadmin)  
Item Type  Online Simulation  
Change Log(History) 


Model Contents URL 
http://cerebellum.neuroinf.jp/modules/xoonips/detail.php?item_id=403
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Model Site Name  Cerebellar Platform  
Simulator Name  Original C program  
Simulator Version  
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