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[projects] minor fixes, change supervisor for some projects

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This commit is contained in:
Jan Grewe
2021-02-01 14:07:44 +01:00
parent ea8a4922a4
commit b55b5789dd
7 changed files with 39 additions and 34 deletions
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32
projects/project_stimulus_reconstruction/stimulus_reconstruction.tex
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@@ -11,27 +11,29 @@
%%%%%%%%%%%%%% Questions %%%%%%%%%%%%%%%%%%%%%%%%%
\section*{Reverse reconstruction of the stimulus that evoked a neuronal response.}
To analyse the encoding properties of a neuron one often calculates the
Spike-Triggered-Average (STA). The STA is the average stimulus that
When analyzing neuronal responses we want to figure out which aspects of the stimulus are actually encoded in the neuronal response.
One way to do this is to calculate the
Spike-Triggered-Average (STA) and use it to reversely estimate which aspects of the stimulus are encoded in the resopnse.
The STA is the average stimulus that
led to a spike in the neuron:
\[ STA(\tau) = \frac{1}{n} \displaystyle\sum_{i=1}^{n}{s(t_i - \tau)} \]
where $n$ is the number of spikes and $t_i$ is the time of the
$i_{th}$ spike. $\tau$ is a temporal shift relative to the spike
time. For the beginning let $\tau$ assume values in the range
$\pm50$\,ms. The STA can be estimated by cutting out snippets from the
time.
Another approach to understand the equation is to cut out snippets from the
stimulus that are centered on the respective spike time and by
subsequently averaging these stimulus snippets. The STA can be used to
reconstruct the stimulus from the neuronal response (reverse
reconstruction). The reconstructed stimulus can then be compared to
the original stimulus and provides a good impression about the
features that are encoded in the neuronal response.
subsequently averaging these stimulus snippets.
\begin{questions}
\question In the accompanying data files you find the spike
responses of a p-type electroreceptor afferent (P-unit) and a
pyramidal neuron recorded in the hindbrain of the weakly electric
fish \textit{Apteronotus leptorhynchus}. The respective stimuli are
stored in separate files. The neron is stimulated with an amplitude
stored in separate files. The neuron is stimulated with an amplitude
modulation of the fish's own electric field. The stored stimulus
trace is the modulator that is applied to the field and is
dimensionless, i.e. it has no unit. The data is sampled with
@@ -39,7 +41,15 @@ features that are encoded in the neuronal response.
seconds. Start with the P-unit and, in the end, apply the same
analyzes/functions to the pyramidal cell.
\begin{parts}
\part Estimate the STA and plot it. What does it tell?
\part Familiarize yourself with the cellular responses and the stimulus.
\part Estimate the STA and plot it. For the beginning let $\tau$ assume values in the range
$\pm50$\,ms. What does it tell?
\end{parts}
\question The STA can be used to reconstruct the stimulus from the neuronal response (reverse
reconstruction) by convolution of the spiking response with the STA. The reconstructed stimulus can then be compared to
the original stimulus and provides a good impression about the
features that are encoded in the neuronal response.
\begin{parts}
\part Implement a function that does the reverse reconstruction and uses the STA to reconstruct the stimulus.
\part Implement a function that estimates the reconstruction quality.
\part Test the robustness of the reconstruction: Estimate