What effect do EPSPs and IPSPs have on the probability of triggering an action potential?

    a.    The probability is decreased by EPSPs and increased by IPSPs.
    b.    The probability is decreased by EPSPs and decreased by IPSPs.
    c.    The probability is increased by EPSPs and increased by IPSPs.
    *d.    The probability is increased by EPSPs and decreased by IPSPs.