A model of working memory for encoding multiple items (Ursino et al, in press)

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Accession:267297
We present an original neural network model, based on oscillating neural masses, to investigate mechanisms at the basis of working memory in different conditions. Simulations show that the trained network is able to desynchronize up to nine items without a fixed order using the gamma rhythm. Moreover, the network can replicate a sequence of items using a gamma rhythm nested inside a theta rhythm. The reduction in some parameters, mainly concerning the strength of GABAergic synapses, induce memory alterations which mimic neurological deficits. Finally, the network, isolated from the external environment simulates an“imagination phase”.
Reference:
1 . Ursino M, Cesaretti N, Pirazzini G (in press) A model of working memory for encoding multiple items and ordered sequences exploiting the theta-gamma code Cognitive Neurodynamics
Model Information (Click on a link to find other models with that property)
Model Type: Neural mass; Synapse; Realistic Network;
Brain Region(s)/Organism:
Cell Type(s):
Channel(s):
Gap Junctions: Gap junctions;
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: MATLAB;
Model Concept(s): Gamma oscillations;
Implementer(s): Ursino, Mauro [mauro.ursino at unibo.it];
% Lo script richiede che siano già costruiti i pattern; si faccia uso della prima sezione
% di MAIN a tal scopo.
%% test rete intera (recall di sequenze) + Working Memory 
clc
MAIN
t_sim=1.8;
dt=0.0001;
t=0:dt:t_sim;

train_flag=0; 
load_sinapsi
    A_L2L2=A_L2L2*2/3;
    A_L3L3=A_L3L3*2/3;
% il set di sinapsi caricate contiene tutti i collegamenti tra L1,L2,L3 +
% WM; tutti i valori sono settati per la funzione di recall di sequenze.

% if SET_PATT==3
%     Wp_L1L1=Wp_L1L1*0.75;
% end

INPUT_WM=zeros(numero_colonne,length(t));
buff=zeros(numero_colonne, round(0.05/dt));
pos=find(corrupt_pattern(all_patterns(:,1))==1);
buff(pos,:)=1;
INPUT_WM(:,51:550)=buff;
buff=zeros(numero_colonne, round(0.05/dt));
pos=find(corrupt_pattern(all_patterns(:,2))==1);
buff(pos,:)=1;
INPUT_WM(:,6051:6550)=buff;
buff=zeros(numero_colonne, round(0.05/dt));
pos=find(corrupt_pattern(all_patterns(:,3))==1);
buff(pos,:)=1;
INPUT_WM(:,12051:12550)=buff;
% buff=zeros(numero_colonne, round(0.05/dt));
% pos=find(corrupt_pattern(all_patterns(:,4))==1);
% buff(pos,:)=1;
% INPUT_WM(:,24051:24550)=buff;

reteWM_sim, IN0=INPUT_WM*600+np0;

line = 1.0;
font = 12;
figure
subplot(511), hold on, ylabel('Input'), xlim([0 t_sim])
plot(t,sum(IN0(pos1,:))/size(pos1,2),'b','linewidth',line)
plot(t,sum(IN0(pos2,:))/size(pos2,2),'r','linewidth',line)
plot(t,sum(IN0(pos3,:))/size(pos3,2),'g','linewidth',line)
% plot(t,sum(IN0(pos4,:))/size(pos4,2),'r--','linewidth',line)
set(gca,'fontsize',font)

subplot(512), hold on, ylabel('z_p_,_W_M(Hz)'), axis([0 t_sim 0 5])
plot(t,sum(zp0(pos1,:))/size(pos1,2),'b ','linewidth',line)
plot(t,sum(zp0(pos2,:))/size(pos2,2),'r','linewidth',line)
plot(t,sum(zp0(pos3,:))/size(pos3,2),'g','linewidth',line)
plot(t,sum(zp0(pos4,:))/size(pos4,2),'k','linewidth',line)
plot(t,sum(zp0(pos5,:))/size(pos5,2),'c','linewidth',line)
plot(t,sum(zp0(pos6,:))/size(pos6,2),'b--','linewidth',line)
plot(t,sum(zp0(pos7,:))/size(pos7,2),'r--','linewidth',line)
plot(t,sum(zp0(pos8,:))/size(pos8,2),'g--','linewidth',line)
plot(t,sum(zp0(pos9,:))/size(pos9,2),'k--','linewidth',line)
set(gca,'fontsize',font)

subplot(513),  hold on, ylabel('z_p_,_L_1(Hz)'), axis([0 t_sim 0 5])
plot(t,sum(zp1(pos1,:))/size(pos1,2),'b','linewidth',line)
plot(t,sum(zp1(pos2,:))/size(pos2,2),'r','linewidth',line)
plot(t,sum(zp1(pos3,:))/size(pos3,2),'g','linewidth',line)
plot(t,sum(zp1(pos4,:))/size(pos4,2),'k','linewidth',line)
plot(t,sum(zp1(pos5,:))/size(pos5,2),'c','linewidth',line)
plot(t,sum(zp1(pos6,:))/size(pos6,2),'b--','linewidth',line)
plot(t,sum(zp1(pos7,:))/size(pos7,2),'r--','linewidth',line)
plot(t,sum(zp1(pos8,:))/size(pos8,2),'g--','linewidth',line)
plot(t,sum(zp1(pos9,:))/size(pos9,2),'k--','linewidth',line)
set(gca,'fontsize',font)

subplot(514), hold on, ylabel('z_p_,_L_2(Hz)'), axis([0 t_sim 0 5])
plot(t,sum(zp2(pos1,:))/size(pos1,2),'b','linewidth',line)
plot(t,sum(zp2(pos2,:))/size(pos2,2),'r','linewidth',line)
plot(t,sum(zp2(pos3,:))/size(pos3,2),'g','linewidth',line)
plot(t,sum(zp2(pos4,:))/size(pos4,2),'k','linewidth',line)
plot(t,sum(zp2(pos5,:))/size(pos5,2),'c','linewidth',line)
plot(t,sum(zp2(pos6,:))/size(pos6,2),'b--','linewidth',line)
plot(t,sum(zp2(pos7,:))/size(pos7,2),'r--','linewidth',line)
plot(t,sum(zp2(pos8,:))/size(pos8,2),'g--','linewidth',line)
plot(t,sum(zp2(pos9,:))/size(pos9,2),'k--','linewidth',line)
set(gca,'fontsize',font)

subplot(515), hold on, ylabel('z_p_,_L_3(Hz)'), xlabel('time (s)'), axis([0 t_sim 0 5])
plot(t,sum(zp3(pos1,:))/size(pos1,2),'b','linewidth',line)
plot(t,sum(zp3(pos2,:))/size(pos2,2),'r','linewidth',line)
plot(t,sum(zp3(pos3,:))/size(pos3,2),'g','linewidth',line)
plot(t,sum(zp3(pos4,:))/size(pos4,2),'k','linewidth',line)
plot(t,sum(zp3(pos5,:))/size(pos5,2),'c','linewidth',line)
plot(t,sum(zp3(pos6,:))/size(pos6,2),'b--','linewidth',line)
plot(t,sum(zp3(pos7,:))/size(pos7,2),'r--','linewidth',line)
plot(t,sum(zp3(pos8,:))/size(pos8,2),'g--','linewidth',line)
plot(t,sum(zp3(pos9,:))/size(pos9,2),'k--','linewidth',line)
set(gca,'fontsize',font)
legend('obj1','obj2','obj3','obj4','obj5','obj6','obj7', 'obj8','obj9')

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