diff --git a/multirecording_spikeanalysis.py b/multirecording_spikeanalysis.py
index 85df809..281037c 100644
--- a/multirecording_spikeanalysis.py
+++ b/multirecording_spikeanalysis.py
@@ -6,6 +6,7 @@
 import pandas as pd
 import matplotlib.pyplot as plt
 
+from collections import defaultdict
 from scipy.stats import sem, ranksums, fisher_exact, wilcoxon
 from statistics import mean, StatisticsError
 from sklearn.decomposition import PCA
@@ -439,9 +440,9 @@ def get_spike_specs(self):
 
     def get_unit_timestamps(self):
         """
-        creates a dictionary of units to spike timestamps
-        keys are unit ids (int) and values are spike timestamps for
-        that unit (numpy arrays)and assigns dictionary to self.unit_timestamps
+        Creates a dictionary of units to spike timestamps.
+        Keys are unit ids (int) and values are spike timestamps for that unit (numpy arrays),
+        and assigns dictionary to self.unit_timestamps.
 
         Args:
             None
@@ -450,21 +451,16 @@ def get_unit_timestamps(self):
             None
         """
 
-        unit_timestamps = {}
-        for spike in range(len(self.timestamps_var)):
-            if self.unit_array[spike] in unit_timestamps.keys():
-                timestamp_list = unit_timestamps[self.unit_array[spike]]
-                timestamp_list = np.append(
-                    timestamp_list, self.timestamps_var[spike]
-                )
-                unit_timestamps[self.unit_array[spike]] = timestamp_list
-            else:
-                unit_timestamps[self.unit_array[spike]] = self.timestamps_var[
-                    spike
-                ]
+        # Initialize a defaultdict for holding lists
+        unit_timestamps = defaultdict(list)
+        default_dict = defaultdict(lambda: np.array([]))
 
-        self.unit_timestamps = unit_timestamps
+        # Loop through each spike only once
+        for spike, unit in enumerate(self.unit_array):
+            # Append the timestamp to the list for the corresponding unit
+            unit_timestamps[unit].append(self.timestamps_var[spike])
 
+        self.unit_timestamps = unit_timestamps
 
 class EphysRecordingCollection:
     """