Blow Control
Although we are deliberately minimising the amount of practical information in this manual, and referring users to the accompanying Plymouth book instead for this purpose, one subject we can usefully mention here is that of destroying the membrane patch in order to enter whole-cell recording mode. There are several ways of doing this, one of which is just by providing mechanical suction to the electrode, but a simple alternative is to provide a large depolarising pulse at the electrode, to destroy the patch electrically. This is not a new technique, but we thought we'd give it a more appropriate name! So, as an alternative to suction, here we describe the "blow" control (and the name is also appropriate if one regards the membrane patch as a fuse). By depressing the blow switch, which has a momentary action, a single depolarising pulse of about 1.4V is applied to the electrode, for the period set by the blow control. This is a single-turn control with a logarithmic law, and the minimum and maximum pulse duration's are 0.2msec and 50msec respectively. The logarithmic law means that the pulse duration is 5msec when the control is at its mid position. Our suggestions for its use are to start with a short pulse (or few), and if that doesn't work, then try some longer ones.
