diff --git a/src/Ironpen.jl b/src/Ironpen.jl
index a2d1810..3caefc1 100644
--- a/src/Ironpen.jl
+++ b/src/Ironpen.jl
@@ -36,7 +36,7 @@ using .interface
     Todo:
         [] using RL to control learning signal
         [] consider using Dates.now() instead of timestamp because time_stamp may overflow
-        [1] training should include adjusting α, neuron membrane potential decay factor
+        [*1] training should include adjusting α, neuron membrane potential decay factor
             which defined by neuron.tau_m formula in type.jl
 
         [DONE] each knowledgeFn should have its own noise generater