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

\newcommand{\ptitle}{Photoreceptor activity}
\input{../header.tex}
\firstpagefooter{Supervisor: Jan Grewe}{phone: 29 74588}%
{email: jan.grewe@uni-tuebingen.de}

\begin{document}

\input{../instructions.tex}


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\section*{Analysis of insect photoreceptor data.}
In this project you will analyse data from intracellular recordings of
a fly R\.1--6 photoreceptor. The membrane potential of the
photoreceptor was recorded while the cell was stimulated with a
light stimulus.

\begin{questions}
  \question{} The accompanying dataset (photoreceptor\_data.zip)
  contains seven mat files. Each of these holds the data from one
  stimulus intensity. In each file are three variables.  (i)
  \textit{voltage} a matrix with the recorded membrane potential from
  10 consecutive trials, (ii) \textit{time} a matrix with the
  time-axis for each trial, and (iii) \textit{trace\_meta} a structure
  that stores several metadata. This is the place where you find the
  \emph{amplitude}, that is the voltage that drives the light
  stimulus, i.e. the light-intensity.
  
  \begin{parts}
    \part{} Create a plot of the raw data. Plot the average response as
    a function of time. This plot should also show the
    across-trial variability.\\[0.5ex]
    \part{} You will notice that the responses have three main parts, a
    pre-stimulus phase, the phase in which the light was on, and
    finally a post-stimulus phase. Create an characteristic curve that
    plots the response strength as a function of the stimulus
    intensity for the ``onset'' and the ``steady state''
    phases.\\[0.5ex]
    \part{} The light switches on at time zero. Estimate the delay between stimulus.\\[0.5ex]
    \part{} You may also decide to analyze the post-stimulus response in some
    more detail.
  \end{parts}
\end{questions}

\end{document}
