Confidence intervals in Plots (Normal distribution)

I would like to know how to plot the 68% confidence interval of a Gaussian in such a way the resulting image looks similar to this one:

I am trying to do that with R, but I want to resort to Matlab again for my research and I want to see its abilities for statistics. I would compute the histogram as follows. The input comes from the CODAchain1.txt attached.

ic_table_file1 = 'CODAchain1.txt';
%%Read tables
codachain = load(ic_table_file1);

%%Length params
snum=1000;
media=mean(codachain(1:snum,2));
sdev=std(codachain(1:snum,2));
vector1=codachain(1:snum,2);
vector1=sort(vector1);

%Histogram
figure(2);
hold on;

min_bin=min(vector1);
max_bin=max(vector1);
inc_bin=(max_bin-min_bin)/40;
binranges = min_bin:inc_bin:max_bin;
[bincounts,ind] = histc(vector1(:),binranges);
sumatot=sum(bincounts(:));
bar(binranges,bincounts/sumatot,'m');
mu=media;
sigma=sdev;
analytic = min_bin:inc_bin:max_bin;
Y = normpdf(analytic,mu,sigma);
sumatotY=sum(Y(:));
plot(analytic,Y/sumatotY);
xlim([min_bin max_bin])

I don't know how would I be able to make the confidence interval that appears in the first image.

Thank you very much.