diff --git a/core/src/main/java/network/aika/Model.java b/core/src/main/java/network/aika/Model.java
index 9aebdd201..876598d81 100644
--- a/core/src/main/java/network/aika/Model.java
+++ b/core/src/main/java/network/aika/Model.java
@@ -41,7 +41,7 @@ public class Model implements Writable {
 
     private long N = 0;
 
-    private SuspensionCallback suspensionCallback;
+    public SuspensionCallback suspensionCallback;
     private final AtomicLong retrievalCounter = new AtomicLong(0);
     private final AtomicLong thoughtIdCounter = new AtomicLong(0);
 
@@ -214,15 +214,6 @@ public void close() throws IOException {
         suspensionCallback.close();
     }
 
-    public Object modelClass(String clazzName) {
-        try {
-            Class clazz = getClass().getClassLoader().loadClass(clazzName);
-            return clazz.getConstructor().newInstance();
-        } catch (Exception e) {
-            throw new RuntimeException(e);
-        }
-    }
-
     @Override
     public void write(DataOutput out) throws IOException {
         out.writeLong(N);
diff --git a/core/src/main/java/network/aika/callbacks/SuspensionCallback.java b/core/src/main/java/network/aika/callbacks/SuspensionCallback.java
index a48e8080d..13096baa5 100644
--- a/core/src/main/java/network/aika/callbacks/SuspensionCallback.java
+++ b/core/src/main/java/network/aika/callbacks/SuspensionCallback.java
@@ -59,4 +59,13 @@ public interface SuspensionCallback {
     void loadIndex(Model m);
 
     void saveIndex(Model m) throws IOException;
+
+    default Object modelClass(String clazzName, Model model) {
+        try {
+            Class clazz = model.getClass().getClassLoader().loadClass(clazzName);
+            return clazz.getConstructor().newInstance();
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
 }
diff --git a/core/src/main/java/network/aika/elements/neurons/Neuron.java b/core/src/main/java/network/aika/elements/neurons/Neuron.java
index 92a2227da..e57082199 100644
--- a/core/src/main/java/network/aika/elements/neurons/Neuron.java
+++ b/core/src/main/java/network/aika/elements/neurons/Neuron.java
@@ -469,7 +469,7 @@ public void write(DataOutput out) throws IOException {
 
     public static Neuron read(DataInput in, Model m) throws Exception {
         String neuronClazz = in.readUTF();
-        Neuron n = (Neuron) m.modelClass(neuronClazz);
+        Neuron n = (Neuron) m.suspensionCallback.modelClass(neuronClazz, m);
 
         n.readFields(in, m);
         return n;
diff --git a/core/src/main/java/network/aika/elements/synapses/Synapse.java b/core/src/main/java/network/aika/elements/synapses/Synapse.java
index 4bc06e97d..70787054b 100644
--- a/core/src/main/java/network/aika/elements/synapses/Synapse.java
+++ b/core/src/main/java/network/aika/elements/synapses/Synapse.java
@@ -348,7 +348,7 @@ public void write(DataOutput out) throws IOException {
     public static Synapse read(DataInput in, Model m) throws IOException {
         String synClazz = in.readUTF();
 
-        Synapse s = (Synapse) m.modelClass(synClazz);
+        Synapse s = (Synapse) m.suspensionCallback.modelClass(synClazz, m);
         s.readFields(in, m);
         return s;
     }