From 90cae6c018131e05405c20528eb7c3c385792421 Mon Sep 17 00:00:00 2001
From: Jan Grewe <jan.grewe@g-node.org>
Date: Sun, 22 Jan 2017 13:55:59 +0100
Subject: [PATCH] [project] fixes to input resistance project

---
 .../input_resistance.tex                      | 31 +++++++++++--------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/projects/project_input_resistance/input_resistance.tex b/projects/project_input_resistance/input_resistance.tex
index 8cff3f4..189aefa 100644
--- a/projects/project_input_resistance/input_resistance.tex
+++ b/projects/project_input_resistance/input_resistance.tex
@@ -30,18 +30,20 @@
 
 %%%%%%%%%%%%%% Questions %%%%%%%%%%%%%%%%%%%%%%%%%
 \section*{Estimating cellular properties of different cell types.}
-You will analyse data from intracellular \texit{in vitro} recordings
+You will analyze data from intracellular \textit{in vitro} recordings
 of pyramidal neurons from two different maps of the electrosensory
 lateral line lobe (ELL) of the weakly electric fish
-\textit{Apteronotus leptorhynchus}. The resistance and capacitance of
-the membrane are typically estimated by injecting hyperpolarizing
-current pulses into the cell. From the respective responses we can
-calculate the membrane resistance by applying Ohm's law ($U = R \cdot
-I$). To estimate the membrane capacitance we need to fit an
-exponential function $y = a \cdot e^{(b \cdot x)}$to the response to
-get the membrane time-constant $\tau$. With the knowledge of $R$ and
-$\tau$ we can estimate the capacitance $C$ from the simple relation
-$\tau = R \cdot C$.
+\textit{Apteronotus leptorhynchus}. The membrane resistance and the
+membrane capacitance are fundamental properties of a neuron that have
+a great influence on the coding properties of the cell. They are
+typically estimated by injecting pulses of hyperpolarizing current
+into the cell. From the respective responses we can calculate the
+membrane resistance by applying Ohm's law ($U = R \cdot I$). To
+estimate the membrane capacitance we need to fit an exponential
+function of the form $y = a \cdot e^{(-x/\tau)}$ to the response to get the
+membrane time-constant $\tau$. With the knowledge of $R$ and $\tau$ we
+can estimate the capacitance $C$ from the simple relation $\tau = R
+\cdot C$.
 
 \begin{questions}
   \question{} The accompanying dataset (input\_resistance.zip)
@@ -59,13 +61,16 @@ $\tau = R \cdot C$.
     a function of time. This plot should also show the across-trial
     variability. Also plot the time-course of the injected
     current. \\[0.5ex]
-    \part{} Estimate the imput resistances of each cell.\\[0.5ex]
+    \part{} Estimate the input resistances of each cell.\\[0.5ex]
     \part{} Fit an exponential to the initial few milliseconds of the
     current-on response. Use a gradient-descent approach to do
-    this.\\[0.5ex]
+    this.\\ It is very important to understand the exponential decay
+    function. If you are unsure, play with the function and understand
+    how the parameters influence the decay. (Hint: It might be
+    necessary to transform the data a bit.)\\[0.5ex]
     \part{} Estimate the membrane capacitance of each cell. Compare
     $R$, $I$ and $\tau$ between cells of the two segments.\\[0.5ex]
-    \part{} Optional: use a double exponential and see, if the fit gets better.
+    \part{} Optional: use a double exponential and see, if the fit improves.
   \end{parts}
 \end{questions}