[BUG, MRG] Fix coordinate frame loading from disc for non-scalp EEG recordings and fNIRS

doc/changes/latest.inc

@@ -177,6 +177,8 @@ Bugs
 
 - Fix bug where setting of a montage with fNIRS data got set to "unknown" coordinate frame when it should have been in "head" (:gh:`9630` by `Alex Rockhill`_)
 
+- Fix bug where "seeg", "ecog", "dbs" and "fnirs" data had coordinate frame unknown upon loading from a file when it should have been in "head" (:gh:`9636` by `Alex rockhill`_)
+
 API changes
 ~~~~~~~~~~~
 - In `mne.compute_source_morph`, the ``niter_affine`` and ``niter_sdr`` parameters have been replaced by ``niter`` and ``pipeline`` parameters for more consistent and finer-grained control of registration/warping steps and iteration (:gh:`9505` by `Alex Rockhill`_ and `Eric Larson`_)

mne/channels/tests/test_montage.py

@@ -1362,10 +1362,8 @@ def test_montage_head_frame(ch_type):
     # gh-9446
     data = np.random.randn(2, 100)
     info = create_info(['a', 'b'], 512, ch_type)
-    coord_frame = getattr(
-        FIFF, f'FIFFV_COORD_{"HEAD" if ch_type == "eeg" else "UNKNOWN"}')
     for ch in info['chs']:
-        assert ch['coord_frame'] == coord_frame
+        assert ch['coord_frame'] == FIFF.FIFFV_COORD_HEAD
     raw = RawArray(data, info)
     ch_pos = dict(a=[-0.00250136, 0.04913788, 0.05047056],
                   b=[-0.00528394, 0.05066484, 0.05061559])

mne/io/tag.py

@@ -333,6 +333,10 @@ def _read_coord_trans_struct(fid, tag, shape, rlims):
     FIFF.FIFFV_MEG_CH: FIFF.FIFFV_COORD_DEVICE,
     FIFF.FIFFV_REF_MEG_CH: FIFF.FIFFV_COORD_DEVICE,
     FIFF.FIFFV_EEG_CH: FIFF.FIFFV_COORD_HEAD,
+    FIFF.FIFFV_ECOG_CH: FIFF.FIFFV_COORD_HEAD,
+    FIFF.FIFFV_SEEG_CH: FIFF.FIFFV_COORD_HEAD,
+    FIFF.FIFFV_DBS_CH: FIFF.FIFFV_COORD_HEAD,
+    FIFF.FIFFV_FNIRS_CH: FIFF.FIFFV_COORD_HEAD,
 }
 
 

mne/io/tests/test_meas_info.py

@@ -317,6 +317,18 @@ def test_io_dig_points(tmpdir):
             read_polhemus_fastscan(dest, on_header_missing='warn')
 
 
+def test_io_coord_frame(tmpdir):
+    """Test round trip for coordinate frame."""
+    fname = tmpdir.join('test.fif')
+    for ch_type in ('eeg', 'seeg', 'ecog', 'dbs', 'hbo', 'hbr'):
+        info = create_info(
+            ch_names=['Test Ch'], sfreq=1000., ch_types=[ch_type])
+        info['chs'][0]['loc'][:3] = [0.05, 0.01, -0.03]
+        write_info(fname, info)
+        info2 = read_info(fname)
+        assert info2['chs'][0]['coord_frame'] == FIFF.FIFFV_COORD_HEAD
+
+
 def test_make_dig_points():
     """Test application of Polhemus HSP to info."""
     extra_points = read_polhemus_fastscan(