diff --git a/csys.lisp b/csys.lisp
index 295d468..1b60291 100644
--- a/csys.lisp
+++ b/csys.lisp
@@ -8,9 +8,9 @@
 
 (in-package :decons/csys)
 
-(defun neuron (proc &key state syns)
+(defun neuron (proc &key state syns env)
   (actor:create 
-    (lambda (msg) (funcall proc msg state syns))))
+    (lambda (msg) (funcall proc msg state syns env))))
 
 (defun synapse (rcvr &optional (op #'identity))
   (lambda (msg)
diff --git a/test-csys.lisp b/test-csys.lisp
index 0f6ea88..68a7036 100644
--- a/test-csys.lisp
+++ b/test-csys.lisp
@@ -2,13 +2,18 @@
 
 (in-package :decons/test-decons)
 
-(defun probe (msg state syns)
-  (let ((t:*test-suite* state))
-    (== (actor:content msg) 42)))
+(defun probe (msg state syns env)
+  (let ((t:*test-suite* env))
+    (== (actor:content msg) (pop state))
+    (lambda (msg) (probe msg state syns env))
+  ))
 
 (deftest test-neuron ()
-  (let ((prb (csys:neuron #'probe :state t:*test-suite*)))
+  (let ((prb (csys:neuron #'probe 
+                          :state '(42 43)
+                          :env t:*test-suite*)))
     (actor:send prb (actor:message 42))
-    (sleep 0.2)
+    (actor:send prb (actor:message 43))
+    (sleep 0.1)
     (actor:stop prb)
     ))