diff --git a/pyhgf/model.py b/pyhgf/model.py
index bdc5a1685..52115cca7 100644
--- a/pyhgf/model.py
+++ b/pyhgf/model.py
@@ -459,6 +459,7 @@ def add_input_node(
         pihat: Union[float, np.ndarray, ArrayLike] = jnp.inf,
         eta0: Union[float, np.ndarray, ArrayLike] = 0.0,
         eta1: Union[float, np.ndarray, ArrayLike] = 1.0,
+        additional_parameters: Optional[Dict] = None,
     ):
         """Create an input node.
 
@@ -477,6 +478,8 @@ def add_input_node(
             The lower bound of the binary process (only relevant if `kind="binary"`).
         eta1 :
             The lower bound of the binary process (only relevant if `kind="binary"`).
+        additional_parameters :
+            Add more custom parameters to the input node.
 
         """
         if kind == "continuous":
@@ -495,6 +498,11 @@ def add_input_node(
                 "time_step": jnp.nan,
                 "value": jnp.nan,
             }
+
+        # add more parameters (optional)
+        if additional_parameters is not None:
+            input_node_parameters = {**input_node_parameters, **additional_parameters}
+
         if input_idx == 0:
             # this is the first node, create the node structure
             self.parameters_structure = {input_idx: input_node_parameters}
@@ -527,6 +535,7 @@ def add_value_parent(
         psis: Optional[Tuple] = None,
         omega: Union[float, np.ndarray, ArrayLike] = -4.0,
         rho: Union[float, np.ndarray, ArrayLike] = 0.0,
+        additional_parameters: Optional[Dict] = None,
     ):
         """Add a value parent to a given set of nodes.
 
@@ -559,6 +568,8 @@ def add_value_parent(
             volatility parent(s)).
         rho :
             The drift of the random walk. Defaults to `0.0` (no drift).
+        additional_parameters :
+            Add more custom parameters to the node.
 
         """
         # how many nodes in structure
@@ -578,6 +589,10 @@ def add_value_parent(
             "rho": rho,
         }
 
+        # add more parameters (optional)
+        if additional_parameters is not None:
+            node_parameters = {**node_parameters, **additional_parameters}
+
         # add a new node to connection structure with no parents
         self.node_structure += (Indexes(None, None, tuple(children_idxs), None),)
 
@@ -632,6 +647,7 @@ def add_volatility_parent(
         psis: Optional[Tuple] = None,
         omega: Union[float, np.ndarray, ArrayLike] = -4.0,
         rho: Union[float, np.ndarray, ArrayLike] = 0.0,
+        additional_parameters: Optional[Dict] = None,
     ):
         """Add a volatility parent to a given set of nodes.
 
@@ -663,6 +679,8 @@ def add_volatility_parent(
             volatility parent(s)).
         rho :
             The drift of the random walk. Defaults to `0.0` (no drift).
+        additional_parameters :
+            Add more custom parameters to the node.
 
         """
         # how many nodes in structure
@@ -682,6 +700,10 @@ def add_volatility_parent(
             "rho": rho,
         }
 
+        # add more parameters (optional)
+        if additional_parameters is not None:
+            node_parameters = {**node_parameters, **additional_parameters}
+
         # add a new node to the connection structure with no parents
         self.node_structure += (Indexes(None, None, None, tuple(children_idxs)),)