diff --git a/Runtime/Scripts/Core/Cluster.cs b/Runtime/Scripts/Core/Cluster.cs
index 3264d8a..50ab0a0 100644
--- a/Runtime/Scripts/Core/Cluster.cs
+++ b/Runtime/Scripts/Core/Cluster.cs
@@ -382,14 +382,21 @@ namespace NanoBrain {
             }
 
             // Otherwise find the stalest cluster?
-            Cluster stalestCluster = this.siblingClusters[0];
-            for (int ix = 1; ix < this.siblingClusters.Length; ix++) {
-                if (this.siblingClusters[ix].defaultOutput.stale > stalestCluster.defaultOutput.stale)
-                    stalestCluster = this.siblingClusters[ix];
-            }
+            // Cluster stalestCluster = this.siblingClusters[0];
+            // for (int ix = 1; ix < this.siblingClusters.Length; ix++) {
+            //     if (this.siblingClusters[ix].defaultOutput.stale > stalestCluster.defaultOutput.stale)
+            //         stalestCluster = this.siblingClusters[ix];
+            // }
 
-            RemoveThingCluster(stalestCluster);
-            return stalestCluster;
+            // Otherwise find longest unused cluster
+            Cluster unusedCluster = this.siblingClusters[0];
+            for (int ix = 1; ix < this.siblingClusters.Length; ix++) {
+                if (this.siblingClusters[ix].defaultOutput.lastUpdate < unusedCluster.defaultOutput.lastUpdate)
+                    unusedCluster = this.siblingClusters[ix];
+            }
+            
+            RemoveThingCluster(unusedCluster);
+            return unusedCluster;
         }
 
         private void RemoveThingCluster(Cluster cluster) {
diff --git a/Runtime/Scripts/Core/Neuron.cs b/Runtime/Scripts/Core/Neuron.cs
index 16d4a1a..c622bcf 100644
--- a/Runtime/Scripts/Core/Neuron.cs
+++ b/Runtime/Scripts/Core/Neuron.cs
@@ -213,11 +213,23 @@ namespace NanoBrain {
         public Action WhenFiring;
 
 
-        public virtual bool isSleeping => this.outputMagnitude == 0;
+        public virtual bool isSleeping => Time.time - this.lastUpdate > this.timeToSleep; //this.outputMagnitude == 0;
+        public void SleepCheck() {
+            if (this.isSleeping) {
+#if UNITY_MATHEMATICS
+                this.bias = new float3(0, 0, 0);
+#else
+                this.bias = new Vector3(0,0,0);
+#endif
+            }
+        }
 
+        // [NonSerialized]
+        // public int stale = 1000;
         [NonSerialized]
-        public int stale = 1000;
-        public readonly int staleValueForSleep = 20;
+        public float lastUpdate = 0;
+        // public readonly int staleValueForSleep = 20;
+        public readonly float timeToSleep = 1f;
 
         /// \copydoc NanoBrain::Nucleus::ShallowCloneTo
         public override Nucleus ShallowCloneTo(Cluster newParent) {
@@ -288,8 +300,18 @@ namespace NanoBrain {
         }
 
         public override void UpdateStateIsolated() {
+            CheckSleepingSynapses();
             var result = Combinator();
             this.outputValue = Activator(result);
+            this.lastUpdate = Time.time;
+        }
+
+        protected void CheckSleepingSynapses() {
+            foreach (Synapse synapse in this.synapses) {
+                if (synapse.isSleeping) {
+                    synapse.neuron.outputValue = Vector3.zero;
+                }
+            }
         }
 
         #region Combinator
@@ -524,7 +546,8 @@ namespace NanoBrain {
         }
 
         public void ProcessStimulusDirect(Vector3 inputValue) { //}, int thingId = 0, string thingName = null) {
-            this.stale = 0;
+            // this.stale = 0;
+            this.lastUpdate = Time.time;
             this.bias = inputValue;
             this.parent.UpdateFromNucleus(this);
         }
diff --git a/Runtime/Scripts/Core/Synapse.cs b/Runtime/Scripts/Core/Synapse.cs
index 63bacf7..e71130d 100644
--- a/Runtime/Scripts/Core/Synapse.cs
+++ b/Runtime/Scripts/Core/Synapse.cs
@@ -28,6 +28,12 @@ namespace NanoBrain {
             this.neuron = nucleus;
             this.weight = weight;
         }
+
+        public bool isSleeping {
+            get {
+                return this.neuron.isSleeping;
+            }
+        }
     }
 
 }
\ No newline at end of file