Multichannel Systems MC_Rack Manual - Manual (Page 137)

MC_Rack Features
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Select from the “Spike Count” drop down menu either “Single Spike” or values from 2 to 100.
This corresponds with the number of spikes that have to be detected in the defined time window
to fulfill the criteria to generate a feedback. The frequency resulting from the selected
combination of time window and spike count is also shown in the drop down menu in brackets.
If more than one electrode and a spike count larger than one is selected, the selection Single
Rate / Overall Rate becomes available. “Single Rate” means that the spike rate of each selected
electrode is counted separately, and that the given spike count has to be reached on any of these
electrodes to set the logical state of this channel on TRUE. “Overall Rate” means that the spikes
of all selected channels are counted together, and that the combined spike count in the selected
time window must reach the threshold to generate the logical state TRUE. If more than one
electrode and “Single Spike”, or “Single Rates” is selected, it is necessary to combine the logical
states of the different electrodes with the functions “AND” or “OR”.
If “AND” is selected, a feedback is generated only if all electrodes have the logical state TRUE
at the same time. If “OR” is selected, a TTL is generated if any of the electrodes has the logical
state TRUE.
The length of the TTL is determined by the overlap (AND) or addition (OR) of the TRUE states
of the individual electrodes.
Please see the following example:
When selecting “Overall Rate” or one channel only, the logic option “And” or “Or” is not
applicable.
Rate Detection
Important: For the purpose of this feature, a Rate is defined as the number of events in
the selected time window. The time window is not a fixed time bin, but a moving window.
For example if the window is set to 1 s, and a rate of 10 Hz is set as condition, the condition
is fulfilled as soon as ten events within a second are detected. It may not happen that these
ten events fall by chance in two separate time bins and are therefore not counted as 10 Hz.