[pointprocesses] improved code

pointprocesses/lecture/pointprocesses-chapter.tex

@@ -25,9 +25,9 @@
 \item Multitrial firing rates
 \item Better explain difference between ISI method and PSTHes. The
   latter is dependent on precision of spike times the former not.
-\item Choice of bin width for PSTH, kernel width, also in relation sto
+\item Choice of bin width for PSTH, kernel width, also in relation to
   stimulus time scale
-\item Kernle firing rate: discuss different kernel shapes, in
+\item Kernel firing rate: discuss different kernel shapes, in
   particular causal kernels (gamma, exponential), relation to synaptic
   potentials
 \end{itemize}