Multichannel Systems LTP-Director Manual - Manual (Page 37)

LTP-Director
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Test Pulse Parameter
Next step in setting up an experiment is to define the pulse parameters for your stimulation test
pulse. You can determine the shape of the pulse, the stimulus paradigm and the pulse interval.
The stimulation test pulse is for testing the response of the slices and for selecting the stimulation
electrodes at each slice.
Note: It is not possible to change pulse parameter while the stimulation is running!
Pulse Shape
The pulse shape of a stimulus pulse is biphasic symmetric rectangular. The parameters are the
negative or positive sign of the first pulse phase, the duration of each phase, and the amplitude
of the pulse.
The phase duration refers to one phase of a biphasic pulse, for example100
s, as shown
in the picture above. The total length of the pulse will be double the phase duration.
For MEA electrodes, it is recommended to use biphasic negative / positive pulses.
The amplitude of the stimulus test pulse has to be an integral number in a range between
0 and 8000 mV. Out of these range an error message appears. Usually, pulse amplitudes
between 500 and 3500 mV are enough to elicit responses in a hippocampal slice.
Stimulus Paradigm
Apart from single pulses, it is also possible to apply paired pulses to check for short term plasticity.
Using a paired pulse, you have to define the "IPI = inter pulse interval" from a drop down
menu in units of milliseconds.
According to the stimulus paradigm the analysis parameter will change: Using single pulse,
you have one region of interest (ROI), using paired pulse paradigm, you will have two regions
of interest.