User manual

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CHAPTER 10 – Automated Experiments using Automated Perfusion
Control
Note: we have recently published a paper on using WinLTP for Automated Perfusion experiments in the
Journal of Neuroscience Methods:
Anderson WW, Fitzjohn SM and Collingridge GL (2012) Automated Multi-Slice Extracellular
and Patch-Clamp Experiments using the WinLTP Data Acquisition System with Automated
Perfusion Control, J Neurosci. Methods, 207:148-160.
This paper should be a good, quick synopsis of using automated perfusion in WinLTP.
10.1 Automated Perfusion Control
Although Sequential Protocol Scripting can generate all the stimulation pulses needed for the typical LTP
experiment after a stable baseline has been achieved, manual changing of bath perfusion fluids is still
required. The big advance in WinLTP 2.00 is automated perfusion control by adding the Perfuse
statement to sequential protocol scripting (Fig. 10.2.7.2B).
This means that once baseline stability has been achieved, for extracellularly recorded experiments, you
don’t have to stay around watching the experiment in order to change solutions – because unlike patch-
clamping, you can’t do much to rectify an extracellular electrode recording problem anyways. You can go
read a paper in peace, reanalyse yesterday’s experiment in peace, run another slice, or go to the pub.
You don’t have to stay around ‘watching paint dry’.
WinLTP can control up to four perfusion lines. Slow0 Perfusion Change can control one perfusion line by
making only ‘slow’ changes BETWEEN PxSweeps. The same holds for Slow1 Perfusion Change.
However, Fast0 Perfusion Change can control one perfusion line by making ‘fast’ changes DURING
sweeps AS WELL AS BETWEEN sweeps. The same holds for Fast1 Perfusion Change. Also, Fast0
and/or Fast1 Perfusion change can control piezo steppers between sweeps, but this is discussed in
automated perfusion control for patch-clamping.
Normally WinLTP would be using Slow0 Perfusion Change for controlling one perfusion line to one
extracellular slice chamber, and that is how extracellular experiments will be dealt with here. However, all
four perfusion line controls (Slow0, Slow1, Fast0 and Fast1) can be used for extracellular slice and patch
clamp experiments.
For slice experiments and fast perfusion changes during a sweep by a stepper, the inexpensive, slowly
operating pinch-valves are appropriate, with valve switching times usually of around 100 ms (although
they can be as low as 10 ms, (personal communication, Joe Cordes, Automate Scientific). For fast single-
line perfusion changes, faster, more expensive valves, such as Lee valves, with 4 ms changing times, are
usually required.