Built color selection infrastructure and assigned stage-specific colors (WIP).

Added 2 plots to methods (WIP).

main.tex

@@ -409,6 +409,14 @@ intensity-adapted envelope $\adapt(t)$ is then passed on from the local
 interneurons to the ascending neurons, where it serves as the basis for the
 following feature extraction stage.
 
+\begin{figure}[!ht]
+    \centering
+    \includegraphics[width=\textwidth]{figures/pathway_stages_pre.pdf}
+    \caption{}
+    \label{fig:pre}
+\end{figure}
+\FloatBarrier
+
 \subsection{Feature extraction by individual neurons}
 
 The ascending neurons extract and encode a number of different features of the
@@ -508,6 +516,14 @@ the resulting high-dimensional feature space, different species-specific song
 patterns are characterized by a distinct combination of feature values, which
 can be read out by a simple linear classifier.
 
+\begin{figure}[!ht]
+    \centering
+    \includegraphics[width=\textwidth]{figures/pathway_stages_feat.pdf}
+    \caption{}
+    \label{fig:stages_feat}
+\end{figure}
+\FloatBarrier
+
 \section{Two mechanisms driving the emergence of intensity-invariant song representation}
 
 \textbf{Definition of invariance (general, systemic):}\\