diff --git a/pointprocesses/code/isis.m b/pointprocesses/code/isis.m
index b0b95ff..cfd0cea 100644
--- a/pointprocesses/code/isis.m
+++ b/pointprocesses/code/isis.m
@@ -5,11 +5,7 @@ function isivec = isis( spikes )
     isivec = [];
     for k = 1:length(spikes)
         difftimes = diff( spikes{k} );
-        if ( size( difftimes, 1 ) == 1 )
-            isivec = [ isivec difftimes ];
-        elseif ( size( difftimes, 2 ) == 1 )
-            isivec = [ isivec difftimes' ];
-        end
+        isivec = [ isivec; difftimes(:) ];
     end
 end
 
diff --git a/pointprocesses/code/isiserialcorr.m b/pointprocesses/code/isiserialcorr.m
index d5b44c1..0daac23 100644
--- a/pointprocesses/code/isiserialcorr.m
+++ b/pointprocesses/code/isiserialcorr.m
@@ -8,8 +8,7 @@ function isicorr = isiserialcorr( isis, maxlag )
     for k = 1:length(lags)
         lag = lags(k);
         if length( isis ) > lag+10
-            cc = corrcoef( [ isis(1:end-lag)', isis(1+lag:end)' ] );
-            isicorr(k) = cc( 1, 2 );
+            isicorr(k) = corr( isis(1:end-lag), isis(lag+1:end) );
         end
     end
     
diff --git a/pointprocesses/code/plotspikestats.m b/pointprocesses/code/plotspikestats.m
new file mode 100644
index 0000000..cede720
--- /dev/null
+++ b/pointprocesses/code/plotspikestats.m
@@ -0,0 +1,73 @@
+%% load data:
+
+clear all
+% alternative 1:
+% pro: no structs. contra: global unknown variables
+load poisson.mat
+whos
+poissonspikes = spikes;
+load pifou.mat;
+pifouspikes = spikes;
+load lifadapt.mat;
+lifadaptspikes = spikes;
+clear spikes;
+% alternative 2:
+% pro: clean code. contra: structs that we do not really know yet
+clear all
+x = load( 'poisson.mat' );
+poissonspikes = x.spikes;
+x = load( 'pifou.mat' );
+pifouspikes = x.spikes;
+x = load( 'lifadapt.mat' );
+lifadaptspikes = x.spikes;
+
+%% spike raster plots:
+subplot(1, 3, 1);
+spikeraster(poissonspikes, 1.0);
+title('Poisson');
+
+subplot(1, 3, 2);
+spikeraster(pifouspikes, 1.0);
+title('PIF OU');
+
+subplot(1, 3, 3);
+spikeraster(lifadaptspikes, 1.0);
+title('LIF adapt');
+
+%% isi histograms:
+maxisi = 300.0;
+subplot(1, 3, 1);
+poissonisis = isis(poissonspikes);
+isihist(poissonisis, 0.001);
+xlim([0, maxisi])
+title('Poisson');
+
+subplot(1, 3, 2);
+pifouisis = isis(pifouspikes);
+isihist(pifouisis, 0.001);
+xlim([0, maxisi])
+title('PIF OU');
+
+subplot(1, 3, 3);
+lifadaptisis = isis(lifadaptspikes);
+isihist(lifadaptisis, 0.001);
+xlim([0, maxisi])
+title('LIF adapt');
+
+%% serial correlations:
+maxlag = 10;
+rrange = [-0.5, 1.05];
+subplot(1, 3, 1);
+isiserialcorr(poissonisis, maxlag);
+ylim(rrange)
+title('Poisson');
+
+subplot(1, 3, 2);
+isiserialcorr(pifouisis, maxlag);
+ylim(rrange)
+title('PIF OU');
+
+subplot(1, 3, 3);
+isiserialcorr(lifadaptisis, maxlag);
+ylim(rrange)
+title('LIF adapt');