diff --git a/meap/physio_regressors.py b/meap/physio_regressors.py
index cf6dc72..808590a 100644
--- a/meap/physio_regressors.py
+++ b/meap/physio_regressors.py
@@ -453,7 +453,7 @@ def process_mri_slices(self, slice_regressors):
                 cardiac_fits[nvox] = np.dot(whole_design, reg.coef_ * cardiac_mask)
                 resp_fits[nvox] = np.dot(whole_design, reg.coef_ * resp_mask)
                 ix_fits[nvox] = np.dot(whole_design, reg.coef_ * ix_mask)
-                drift_fits[nvox] = np.dot(whole_design, reg.coef_ * ix_mask)
+                drift_fits[nvox] = np.dot(whole_design, reg.coef_ * detrend_mask)
                 
             if self.write_4d_nuisance:
                 fitts[nvox] = np.dot(whole_design, reg.coef_)