\documentclass[addpoints,11pt]{exam} \usepackage{url} \usepackage{color} \usepackage{hyperref} \pagestyle{headandfoot} \runningheadrule \firstpageheadrule \firstpageheader{Scientific Computing}{Project Assignment}{11/02/2014 -- 11/05/2014} %\runningheader{Homework 01}{Page \thepage\ of \numpages}{23. October 2014} \firstpagefooter{}{}{{\bf Supervisor:} Jan Benda} \runningfooter{}{}{} \pointsinmargin \bracketedpoints %\printanswers %\shadedsolutions %%%%% listings %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \usepackage{listings} \lstset{ basicstyle=\ttfamily, numbers=left, showstringspaces=false, language=Matlab, breaklines=true, breakautoindent=true, columns=flexible, frame=single, % captionpos=t, xleftmargin=2em, xrightmargin=1em, % aboveskip=11pt, %title=\lstname, % title={\protect\filename@parse{\lstname}\protect\filename@base.\protect\filename@ext} } \begin{document} %%%%%%%%%%%%%%%%%%%%% Submission instructions %%%%%%%%%%%%%%%%%%%%%%%%% \sffamily % \begin{flushright} % \gradetable[h][questions] % \end{flushright} \begin{center} \input{../disclaimer.tex} \end{center} %%%%%%%%%%%%%% Questions %%%%%%%%%%%%%%%%%%%%%%%%% \begin{questions} \question You are recording the activity of a neuron in response to constant stimuli of intensity $I$ (think of that, for example, as a current $I$ injected via a patch-electrode into the neuron). Measure the tuning curve (also called the intensity-response curve) of the neuron. That is, what is the firing rate of the neuron's response as a function of the input $I$. How does this depend on the level of the intrinsic noise of the neuron? The neuron is implemented in the file \texttt{lifspikes.m}. Call it with the following parameters: \begin{lstlisting} trials = 10; tmax = 50.0; input = 10.0; % the input I Dnoise = 1.0; % noise strength spikes = lifspikes( trials, input, tmax, Dnoise ); \end{lstlisting} The returned \texttt{spikes} is a cell array with \texttt{trials} elements, each being a vector of spike times (in seconds) computed for a duration of \texttt{tmax} seconds. The input is set via the \texttt{input} variable, the noise strength via \texttt{Dnoise}. \begin{parts} \part First set the noise \texttt{Dnoise=0} (no noise). Compute and plot the firing rate as a function of the input for inputs ranging from 0 to 20. \part Do the same for various noise strength \texttt{Dnoise}. Use $D_{noise} = 1e-3$, 1e-2, and 1e-1. How does the intrinsic noise influence the response curve? \part Show some interspike interval histograms for some interesting values of the input and the noise strength. \part How does the coefficient of variation $CV_{isi}$ (standard deviation divided by mean) of the interspike intervalls depend on the input and the noise level? \end{parts} \end{questions} \end{document}