Intracortical synaptic potential modulation by presynaptic somatic potential (Shu et al. 2006, 2007)

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Accession:135787
" ... Here we show that the voltage fluctuations associated with dendrosomatic synaptic activity propagate significant distances along the axon, and that modest changes in the somatic membrane potential of the presynaptic neuron modulate the amplitude and duration of axonal action potentials and, through a Ca21- dependent mechanism, the average amplitude of the postsynaptic potential evoked by these spikes. These results indicate that synaptic activity in the dendrite and soma controls not only the pattern of action potentials generated, but also the amplitude of the synaptic potentials that these action potentials initiate in local cortical circuits, resulting in synaptic transmission that is a mixture of triggered and graded (analogue) signals."
References:
1 . Shu Y, Duque A, Yu Y, Haider B, McCormick DA (2007) Properties of action-potential initiation in neocortical pyramidal cells: evidence from whole cell axon recordings. J Neurophysiol 97:746-60 [PubMed]
2 . Shu Y, Hasenstaub A, Duque A, Yu Y, McCormick DA (2006) Modulation of intracortical synaptic potentials by presynaptic somatic membrane potential. Nature 441:761-5 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell; Axon;
Brain Region(s)/Organism:
Cell Type(s): Neocortex V1 pyramidal corticothalamic L6 cell;
Channel(s): I Na,t; I L high threshold; I A; I K; I M; I h; I K,Ca; I_AHP; I_KD;
Gap Junctions:
Receptor(s): GabaA; AMPA; NMDA;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Action Potential Initiation; Detailed Neuronal Models; Action Potentials; Synaptic Integration;
Implementer(s):
Search NeuronDB for information about:  Neocortex V1 pyramidal corticothalamic L6 cell; GabaA; AMPA; NMDA; I Na,t; I L high threshold; I A; I K; I M; I h; I K,Ca; I_AHP; I_KD;
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ShuEtAl20062007
readme.txt
ampa5.mod *
ca.mod *
cad.mod
caL3d.mod *
capump.mod
gabaa5.mod *
Gfluct.mod *
ia.mod *
iahp.mod *
iahp2.mod *
ih.mod
im.mod *
kca.mod *
km.mod *
kv.mod *
na.mod *
NMDA_Mg.mod *
nmda5.mod *
release.mod *
2006_Nature.pdf
2006_Nature_supp.pdf
best_full_axon_decay.hoc
best_full_axon_spike_init.hoc
best_full_axon_spike_init.hoc'A=0
decay_constant.gif
for_decay.m
for_initiation.m
j4a.hoc *
j4a_removedendrite.hoc
j4a_removedendrite1.hoc
j7.hoc *
j8.hoc *
j8_removedendrite.hoc
lcAS3.hoc *
mosinit.hoc
spike_initiation.gif
                            
clear
load seg.dat
difvth1=35;
difvth2=180;
timebin=0.005;
x0=[0,5];x1=[10,15,20,25,30,35,38,40,45,50]; x2=[57.5:7.5:350];
x=[x0,x1,x2];
a=seg(:,2:end);
mn=size(a);
m=mn(2);
delx=x-x(1);
adif=diff(a(:,:),1)./timebin;
%figure;plot(a(:,1))

for ik=1:m
n=200;
start_ap=find((adif(n:end,ik)>=difvth1 & adif(n:end,ik)<=difvth2),1);
start_ap0=find((adif(n:end,1)>=difvth1 & adif(n:end,1)<=difvth2),1);
delt(ik)=(start_ap(1)-start_ap0(1))*timebin*1000; %micron second
vthpos=start_ap(1)+n-1;
vth(ik)=a(vthpos,ik);
if vth(ik)>0
figure;plot(a(2:end,ik),'o')
hold on;plot(adif(1:end,ik),'r.')
xlim([vthpos-1500, vthpos+1500])
ylim([-75 55])
hold on;plot([vthpos,vthpos],[a(vthpos,ik),adif(vthpos-1,ik)],'-c')
hold on;plot([vthpos-1500,vthpos+1500],[vth(ik),vth(ik)],'-g')
hold on;plot([vthpos-1500,vthpos+1500],[adif(vthpos-1,ik),adif(vthpos-1,ik)],'-g')
end
%      delv=-55-vth(ik);
figure(10000);hold on;plot(a(vthpos-400:vthpos+500,ik),'-')
%figure(10000);hold on;plot(a(vthpos-1500:vthpos+1500,ik)+delv,'-')
end

figure;plot(x,delt,'-o')
xlabel('Axon Distance (\mum)')
ylabel('Spike latency (\mus)')

initpos=find(delt==min(delt));
if length(initpos)>2;
xinitpos=initpos(length(initpos)-1);
else
xinitpos=initpos(end);
end
initialpoint=x(xinitpos) 


% delx_iseg=x-x(xinitpos);
% for ik=1:m
% n=200;
% start_ap=find((adif(n:end,ik)>=difvth1 & adif(n:end,ik)<=difvth2),1);
% start_ap_realinit=find((adif(n:end,xinitpos)>=difvth1 & adif(n:end,xinitpos)<=difvth2),1);
% delt_iseg(ik)=start_ap(1)-start_ap_realinit(1);
% end
% holdv=mean(a(1:n,:));
% %v=[holdv; vel];
% vel_iseg=delx_iseg.*0.001./(delt_iseg*timebin);
% holdv_iseg=mean(a(1:n,:));
% velocity_iseg=[x; vel_iseg]';
% delt(end);
% delt_iseg;
% diff(delx)./diff(delt);
% diff(delx_iseg)./diff(delt_iseg);
% delt_iseg_soma=reverse(delt_iseg(1:xinitpos));
% delt_iseg_axon=delt_iseg(xinitpos:end);
% delx_iseg_soma=reverse(delx_iseg(1:xinitpos));
% delx_iseg_axon=delx_iseg(xinitpos:end);
% vel_iseg_soma=abs(diff(delx_iseg_soma,1))./abs(diff(delt_iseg_soma,1))
% vel_iseg_axon=diff(delx_iseg_axon,1)./abs(diff(delt_iseg_axon,1))
% velocity_iseg_soma=[x(1:xinitpos-1)',reverse(vel_iseg_soma)']
% velocity_iseg_axon=[x(xinitpos:end-1)',reverse(vel_iseg_axon)']
% figure;plot(velocity_iseg(:,1),velocity_iseg(:,2),'-o')
% delt
% t1=abs(delt(end));
% t2=abs(delt_axon(end));
% L=x(end);
% initpoint_comput=L*(t2-t1)./(2.*t2)
% initpoint_real=initialpoint

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