diff --git a/multiarea_model/theory_helpers.py b/multiarea_model/theory_helpers.py
index ac3832f4d508afb12fab6132f4b2e01d12db73c4..d9fe25732865e8fc41987cb1332cbeb51f9c5f1c 100644
--- a/multiarea_model/theory_helpers.py
+++ b/multiarea_model/theory_helpers.py
@@ -85,7 +85,7 @@ def nu_0(tau_m, tau_r, V_th, V_r, mu, sigma):
     sigma : float
         Variance of the input current to the neurons in mV
     """
-    if mu <= V_th + (0.95 * abs(V_th) - abs(V_th)):
+    if mu <= V_th - 0.05 * abs(V_th):
         return siegert1(tau_m, tau_r, V_th, V_r, mu, sigma)
     else:
         return siegert2(tau_m, tau_r, V_th, V_r, mu, sigma)