\documentclass[a4paper,12pt,pdftex]{exam} \newcommand{\ptitle}{Neuronal encoding of quantities} \input{../header.tex} \firstpagefooter{Supervisor: Jan Grewe}{phone: 29 74588}% {email: jan.grewe@uni-tuebingen.de} \begin{document} \input{../instructions.tex} %%%%%%%%%%%%%% Questions %%%%%%%%%%%%%%%%%%%%%%%%% \begin{questions} \question The accompanying data {\tt Neuron22.mat} stores a single data matrix {\tt data\_unsorted} containing spikes from a neuron in macaque prefrontal cortex (data courtesy of Prof. Nieder). The task of the monkey was to discriminate point-sets with 1 to 4 points. The first column contains the number of points shown plus one. The remaining columns contain the spike response across 2300\,ms. During the first 500\,ms the monkey was fixating a target. The stimulus was shown for the next 800\,ms. This period was followed by 1000\,ms delay before the monkey was allowed to respond. \begin{parts} \part Plot the data in an appropriate way (e.g. a rasterplot). \part Sort the trials according to the stimulus presented and compute plot for each condition the firing rate as a function of time. The plot should illustrate the average response and the variability of the data. \part Extract the average firing rates for the time intervals 0-499\,ms, 500-1299\,ms and 1300-2299\,ms. Plot them in an appropriate way that illustrates the average and the the across trial variability. Do these measures correlate with the stimulus condition? Test it! \part Use an appropriate test to determine whether the firing rate in the interval 500-1299\,ms is statistically significantly different for 1 vs. 4 points. Is it statistically significantly different from the first 500\,ms period? \end{parts} \end{questions} \end{document}