afni.nimh.nih.gov

You're confusing the Fisher-transformed Z-value with the Z-statistic. The reason the Pearson correlation coefficient is converted to Fisher Z-value in the context (like yours) is for the convenience of Gaussianity assumption at the group level. In other words, the Fisher Z-value is meant to be used as an effect estimate for further parametric analysis, not for significance or p-value; and there is no point talking about comparing Fisher Z-value to t-statistic or p-value. On the other hand, a Z-statistic, similar to t-statistic, provides some evidence about the significance for a hypothesis.

Gang