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800581-2.11 NeurOne System User Manual.doc
Decay fit start (ms)
– Clearing time, the duration of software mute in
milliseconds. No
te that the “mute ramp” starts at -1 ms.
Coefficients 1 & 2
– (Active only if TMS Decay is selected) Determine the shape
of the exponential decay function, which is fitted on the response. Use is
recommended only if there actually is a substantial exponentially decaying
artefact following the TMS artefact. The decay can be caused by relatively slow
discharging of a charge accumulated on the scalp from the TMS pulse. The
function is
where a and b are slope coefficients (these are the user settable coefficients), fs
is sampling frequency and θ1, θ2 and θ3 are fitting parameters determined by the
fit for each TMS-EEG response, to best match the curve to the response.
The shape of the function with negative slope coefficients a and b is a decaying
exponent. With positive slope coefficients, the function would be an increasing
exponent, which would not make much sense in this context. With larger slope
coefficients, the function falls to a lower value more slowly. Slope coefficients are
equal in the sense that a = -50, b = -400 gives the same result as a = -400,
b = -50.
In the figure below, Left: original EEG response to a TMS pulse. Right:
Response after using software TMS Mute with a duration.
