Does anyone have a method for deciding whether a BOLD response is positive or negative in an Event-related design? I've narrowed it down to two possible equations in my mind, but I am open to others.
Equation 1: Positive response is when the sum of all IRF coefficents is greater than 0; Negative response is when the sum of all IRF coefficents is less than 0.
Equation 2: Postive response is when the sum of all IRF coefficents (when each coefficent has the average of the first and last coefficent subtracted out); negative response is when that sum is neagtive.
Any thoughts would be appreciated.
