diff --git a/projects/project_serialcorrelation/serialcorrelation.tex b/projects/project_serialcorrelation/serialcorrelation.tex
index 98dc07e..3950c7a 100644
--- a/projects/project_serialcorrelation/serialcorrelation.tex
+++ b/projects/project_serialcorrelation/serialcorrelation.tex
@@ -9,21 +9,28 @@
 
 \input{../instructions.tex}
 
-
-%%%%%%%%%%%%%% Questions %%%%%%%%%%%%%%%%%%%%%%%%%
+The gymnotiform weakly electric fish \textit{Apteronotus
+  leptorhynchus} has an active electrosensory system.  An electric
+organ generates an electric field surrounding the
+fish. Electroreceptive organs distributed over the whole body of the
+fish sense minute perturbations of the electric field caused by
+objects close to the fish. P-unit electroreceptor afferents send
+information from the electroreceptive organs to the brain. They are
+spontaneously active when the fish is not electrically stimulated,
+that is when the electroreceptors are only stimulated by the fish's
+own unperturbed electric field.
+
+In this project we want to analyze how the baseline firing rates and
+the serial correlations of the interspike intervals vary between
+different P-units.
+
+In the file \texttt{baselinespikes.mat} you find two variables:
+\texttt{cells} is a cell-array with the names of the recorded cells
+and \texttt{spikes} is a cell array containing the spike times in
+seconds of recorded spontaneous activity for each of these cells.
 
 \begin{questions}
-  \question P-unit electroreceptor afferents of the gymnotiform weakly
-  electric fish \textit{Apteronotus leptorhynchus} are spontaneously
-  active when the fish is not electrically stimulated. 
-
-  How do the firing rates and the serial correlations of the
-  interspike intervals vary between different cells?
-
-  In the file \texttt{baselinespikes.mat} you find two variables:
-  \texttt{cells} is a cell-array with the names of the recorded cells
-  and \texttt{spikes} is a cell array containing the spike times in
-  seconds of recorded spontaneous activity for each of these cells.
+  \question Baseline firing rates
   \begin{parts}
     \part Load the data! How many cells are contained in the file?
 
@@ -38,12 +45,21 @@
     \part Compute the firing rate of each cell, i.e. number of spikes per time.
 
     Illustrate the results by means of a histogram and/or box whisker plot.
+  \end{parts}
 
-    \part Compute and plot the serial correlations between interspike intervals up to lag 10.
+  \question Serial correlations
+  \begin{parts}
+    \part Compute and plot the serial correlations between interspike
+    intervals up to lag 10.
 
     What do you observe? In what way are the interspike-interval
     correlations similar betwen the cells? How do they differ?
 
+    \part Illustrate relevant serial correlations with a return
+    map. How is the return map related to what you see in the
+    corresponding raster plot? How is it related to the corresponding
+    serial correlation?
+
     \part Implement a permutation test for computing the significance
     at an appropriate significance level of the serial
     correlations. Keep in mind that you test the correlations at 10