\documentclass[a4paper,12pt,pdftex]{exam}

\newcommand{\ptitle}{Serial ISI correlations}
\input{../header.tex}
\firstpagefooter{Supervisor: Jan Benda}{phone: 29 74573}%
{email: jan.benda@uni-tuebingen.de}

\begin{document}

\input{../instructions.tex}


%%%%%%%%%%%%%% Questions %%%%%%%%%%%%%%%%%%%%%%%%%

\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. 
  \begin{itemize}
  \item How do the firing rates and the serial correlations of the
    interspike intervals vary between different cells?
  \end{itemize}

  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{parts}
    \part Load the data! How many cells are contained in the file?

    \part Plot the spike rasters of a few cells.

    For the presentation, choose a few cells based on the results of
    this project.

    By just looking on the spike rasters, what are the differences
    betwen the cells?

    \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.

    \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 Implement a permutation test for computing the significance
    at a 1\,\% level of the serial correlations. Illustrate for a few
    cells the computed serial correlations and the 1\,\% and 99\,\%
    percentile from the permutation test. At which lag are the serial
    correlations clearly significant?

    \part Are the serial correlations somehow dependent on the firing rate?

    Plot the significant correlations against the firing rate. Do you
    observe any dependence?
  \end{parts}

\end{questions}

\end{document}