Synaptic plasticity can produce and enhance direction selectivity (Carver et al, 2008)

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Accession:116901
" ... We propose a parsimonious model of motion processing that generates direction selective responses using short-term synaptic depression and can reproduce salient features of direction selectivity found in a population of neurons in the midbrain of the weakly electric fish Eigenmannia virescens. The model achieves direction selectivity with an elementary Reichardt motion detector: information from spatially separated receptive fields converges onto a neuron via dynamically different pathways. In the model, these differences arise from convergence of information through distinct synapses that either exhibit or do not exhibit short-term synaptic depression—short-term depression produces phase-advances relative to nondepressing synapses. ..."
Reference:
1 . Carver S, Roth E, Cowan NJ, Fortune ES (2008) Synaptic plasticity can produce and enhance direction selectivity. PLoS Comput Biol 4:e32 [PubMed]
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Model Information (Click on a link to find other models with that property)
Model Type: Realistic Network;
Brain Region(s)/Organism:
Cell Type(s): Electric fish midbrain torus semicircularis neuron;
Channel(s):
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: MATLAB;
Model Concept(s): Oscillations; Depression; Direction Selectivity; Synaptic Convergence;
Implementer(s): Carver, Sean [sean.carver at jhu.edu];
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carver
stimuli
Igamma.m
Igrey.m
Ipreinitseq.m
Isequence.m
Isine.m
                            
function I = Igamma(varargin) 
% IGAMMA Returns intensity of gamma oscillations as a function of time & space
%
% I = IGAMMA(x,t,f_gamma,A_gamma) with 4 args returns, intensity for x & t 
%     I(x,t) = A_gamma*sin(2*pi*f_gamma*t) constant for x
%     More precisely, I = A_gamma*sin(2*pi*ones(length(x),1)*f_gamma*t)
%
% PERIOD = IGAMMA(f_gamma,A_gamma) with 2 args, returns period = 1/f_gamma 
%          The PERIOD function was used in our implementation of
%          the original Chance model to save memory (so that the intensity
%          of only one cycle of the need be handled).
%          It is not used for the present model.
%
% STRING = IGAMMA() with 0 args, returns string '{f_gamma,A_gamma}';
% 
% Code written by SEAN CARVER, last modified 12-5-2007

if nargin==0
  I = '{f_gamma,A_gamma}';
elseif nargin < 4 
  f_gamma = varargin{1};
  I = 1/f_gamma; 
else
  x = varargin{1};
  t = varargin{2};
  f_gamma = varargin{3};
  A_gamma = varargin{4};
  I = A_gamma*sin(2*pi*ones(length(x),1)*f_gamma*t);
end