\documentclass[addpoints,10pt]{exam} \usepackage{url} \usepackage{color} \usepackage{hyperref} \pagestyle{headandfoot} \runningheadrule \firstpageheadrule \firstpageheader{Scientific Computing}{Project Assignment}{11/05/2014 -- 11/06/2014} %\runningheader{Homework 01}{Page \thepage\ of \numpages}{23. October 2014} \firstpagefooter{}{}{} \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=10pt, %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, of sound waves with intensities $I$). 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? \begin{parts} \part 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}. \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. \end{parts} \end{questions} \end{document}