diff --git a/src/Neuron/NeuronBiased.h b/src/Neuron/NeuronBiased.h
index b8ca40ecf21c005271800ac06835c37651d60615..a8e10422ec4bf9159da8ad90365e85af84aecec5 100644
--- a/src/Neuron/NeuronBiased.h
+++ b/src/Neuron/NeuronBiased.h
@@ -30,7 +30,7 @@ namespace lib4neuro {
          * f(x) = x + b
          * @param[in] b Bias
          */
-        LIB4NEURO_API explicit NeuronBiased( double b );
+        LIB4NEURO_API explicit NeuronBiased( double b = 0 );
 
         /**
          * Evaluates 'x + this->bias' and stores the result into the 'state' property