48 lines
1.9 KiB
TeX
48 lines
1.9 KiB
TeX
\documentclass[a4paper,12pt,pdftex]{exam}
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\newcommand{\ptitle}{Onset f-I curve}
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\input{../header.tex}
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\firstpagefooter{Supervisor: Jan Grewe}{phone: 29 74588}%
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{email: jan.grewe@uni-tuebingen.de}
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\begin{document}
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\input{../instructions.tex}
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%%%%%%%%%%%%%% Questions %%%%%%%%%%%%%%%%%%%%%%%%%
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\section*{Quantifying the responsiveness of a neuron using the F-I curve.}
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The responsiveness of a neuron is often quantified using an F-I
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curve. The F-I curve plots the \textbf{F}iring rate of the neuron as a
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function of the stimulus \textbf{I}ntensity.
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\begin{questions}
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\question In the accompanying datasets you find the
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\textit{spike\_times} of an P-unit electroreceptor of the weakly
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electric fish \textit{Apteronotus leptorhynchus} to a stimulus of a
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certain intensity, i.e. the \textit{contrast}. The spike times are
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given in milliseconds relative to the stimulus onset.
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\begin{parts}
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\part For each stimulus intensity estimate the average response
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(PSTH) and plot it. You will see that there are three parts. (i)
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The first 200\,ms is the baseline (no stimulus) activity. (ii)
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During the next 1000\,ms the stimulus was switched on. (iii) After
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stimulus offset the neuronal activity was recorded for further
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825\,ms.
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\part Extract the neuron's activity in the first 50\,ms after
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stimulus onset and plot it against the stimulus intensity,
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respectively the contrast, in an appropriate way.
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\part Fit a Boltzmann function to the FI-curve. The Boltzmann function
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is defined as:
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\begin{equation}
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y=\frac{\alpha-\beta}{1+e^{(x-x_0)/\Delta x}}+\beta,
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\end{equation}
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where $\alpha$ is the starting firing rate, $\beta$ the saturation
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firing rate, $x$ the current stimulus intensity, $x_0$ starting
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stimulus intensity, and $\Delta x$ a measure of the slope.
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\part Plot the fit into the data.
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\end{parts}
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\end{questions}
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\end{document}
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