diff --git a/doc/whats_new.rst b/doc/whats_new.rst
index f028de491..4d8030524 100644
--- a/doc/whats_new.rst
+++ b/doc/whats_new.rst
@@ -16,6 +16,9 @@ Changelog
 Bug
 ~~~
 
+- Allow regular strings as filenames in :meth:`~hnn_core.Cell_response.write` by
+  `Mainak Jas`_ in :gh:456.
+
 API
 ~~~
 
diff --git a/hnn_core/cell_response.py b/hnn_core/cell_response.py
index ee088c58c..f5e8f3912 100644
--- a/hnn_core/cell_response.py
+++ b/hnn_core/cell_response.py
@@ -376,8 +376,10 @@ def write(self, fname):
         Parameters
         ----------
         fname : str
-            String format (e.g., '<pathname>/spk_%d.txt') of the
-            path to the output spike file(s).
+            String format (e.g., 'spk_%d.txt' or 'spk_{0}.txt') of the
+            path to the output spike file(s). If no string format
+            is provided, the trial index will be automatically
+            appended to the file name.
 
         Outputs
         -------
@@ -387,9 +389,23 @@ def write(self, fname):
             2) spike gid, and
             3) gid type
         """
+        fname = str(fname)
+        old_style = True
+        try:
+            fname % 0
+        except TypeError:
+            fname.format(0)
+            old_style = False
+        except TypeError:
+            fname.replace('.txt', '_%d.txt')
 
         for trial_idx in range(len(self._spike_times)):
-            with open(str(fname) % (trial_idx,), 'w') as f:
+            if old_style:
+                this_fname = fname % (trial_idx,)
+            else:
+                this_fname = fname.format(trial_idx)
+            print(f'Writing file {this_fname}')
+            with open(this_fname, 'w') as f:
                 for spike_idx in range(len(self._spike_times[trial_idx])):
                     f.write('{:.3f}\t{}\t{}\n'.format(
                         self._spike_times[trial_idx][spike_idx],
diff --git a/hnn_core/tests/test_cell_response.py b/hnn_core/tests/test_cell_response.py
index c49695b00..24d7c6db6 100644
--- a/hnn_core/tests/test_cell_response.py
+++ b/hnn_core/tests/test_cell_response.py
@@ -44,6 +44,8 @@ def test_cell_response(tmpdir):
     empty_spike = CellResponse(spike_times=[[], []], spike_gids=[[], []],
                                spike_types=[[], []])
     empty_spike.write(tmpdir.join('empty_spk_%d.txt'))
+    empty_spike.write(tmpdir.join('empty_spk.txt'))
+    empty_spike.write(tmpdir.join('empty_spk_{0}.txt'))
     assert empty_spike == read_spikes(tmpdir.join('empty_spk_*.txt'))
 
     assert ("CellResponse | 2 simulation trials" in repr(empty_spike))