# Cannot select Labels while applying inverse operator to Epochs object **URL:** \ **Category:** Support & Discussions\ **Tags:** source-localization, epochs\ **Created:** [May 18, 2023, 9:49pm UTC](https://mne.discourse.group/t/cannot-select-labels-while-applying-inverse-operator-to-epochs-object/6923 "2023-05-18T21:49:02Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![georgekenefati](https://avatars.discourse-cdn.com/v4/letter/g/34f0e0/32.png) [@georgekenefati](https://mne.discourse.group/u/georgekenefati)\ **Post date:** [May 18, 2023, 9:49pm UTC](https://mne.discourse.group/t/cannot-select-labels-while-applying-inverse-operator-to-epochs-object/6923/1 "2023-05-18T21:49:02Z")
In trying to compute STC from an Epochs object from just a select number of labels, I get the following error: `TypeError: cannot unpack non-iterable Exception object`. I did a test run with just one Label object and I get the same error. I don’t understand why the Label becomes construed as an Exception object. Any help would be greatly appreciated. Thanks 🙂 **OS details:** - MNE version: 1.3.0 - operating system: Ubuntu 20.04 **Code snippet:** ```python roi_names = ['rostralanteriorcingulate-lh', 'postcentral-lh', # Left ACC, Left S1, 'insula-lh', 'superiorfrontal-lh', # Left Insula, Left DL-PFC, 'medialorbitofrontal-lh', # Left Medial-PFC 'rostralanteriorcingulate-rh', 'postcentral-rh', # Right ACC, Right S1 'insula-rh', 'superiorfrontal-rh', # Right Insula, Right DL-PFC 'medialorbitofrontal-rh'] # Right Medial-PFC selected_labels = [mne.read_labels_from_annot(subject, regexp=roi, subjects_dir=subjects_dir)[0] for roi in roi_names] apply_inverse_kwargs = dict( epochs=epochs, inverse_operator=inverse_operator, lambda2 = 1. / snr ** 2, # regularizer parameter (λ²) method='dSPM', pick_ori=None, verbose=True) for i in range(int(len(selected_labels)/2)): # half because mne automatically saves both hemispheres #dSPM stc_tmp = mne.minimum_norm.apply_inverse_epochs(label=selected_labels[i], **apply_inverse_kwargs) stc_tmp.save(save_path+f"{sub_num}_{selected_labels[i].name[:-3]}_dSPM",overwrite=True) ``` **Full error:** ```python Preparing the inverse operator for use... Scaled noise and source covariance from nave = 1 to nave = 1 Created the regularized inverter Created an SSP operator (subspace dimension = 1) Created the whitener using a noise covariance matrix with rank 51 (1 small eigenvalues omitted) Computing noise-normalization factors (dSPM)... [done] Picked 52 channels from the data Computing inverse... --------------------------------------------------------------------------- TypeError Traceback (most recent call last) Cell In[22], line 19 16 print(f"************\t{i}\t{selected_labels[i].name}\t\t************\n") 18 #dSPM ---> 19 stc_dSPM_tmp = mne.minimum_norm.apply_inverse_epochs(label=selected_labels[i], 20 **apply_inverse_kwargs) 21 stc_dSPM_tmp.save(save_path+f"{sub_num}_{selected_labels[i].name[:-3]}_{method1}",overwrite=True) 23 #LCMV File :10, in apply_inverse_epochs(epochs, inverse_operator, lambda2, method, label, nave, pick_ori, return_generator, prepared, method_params, use_cps, verbose) File ~/anaconda3/envs/eegenv/lib/python3.9/site-packages/mne/minimum_norm/inverse.py:1269, in apply_inverse_epochs(epochs, inverse_operator, lambda2, method, label, nave, pick_ori, return_generator, prepared, method_params, use_cps, verbose) 1262 stcs = _apply_inverse_epochs_gen( 1263 epochs, inverse_operator, lambda2, method=method, label=label, 1264 nave=nave, pick_ori=pick_ori, verbose=verbose, prepared=prepared, 1265 method_params=method_params, use_cps=use_cps) 1267 if not return_generator: 1268 # return a list -> 1269 stcs = [stc for stc in stcs] 1271 return stcs File ~/anaconda3/envs/eegenv/lib/python3.9/site-packages/mne/minimum_norm/inverse.py:1269, in (.0) 1262 stcs = _apply_inverse_epochs_gen( 1263 epochs, inverse_operator, lambda2, method=method, label=label, 1264 nave=nave, pick_ori=pick_ori, verbose=verbose, prepared=prepared, 1265 method_params=method_params, use_cps=use_cps) 1267 if not return_generator: 1268 # return a list -> 1269 stcs = [stc for stc in stcs] 1271 return stcs File ~/anaconda3/envs/eegenv/lib/python3.9/site-packages/mne/minimum_norm/inverse.py:1164, in _apply_inverse_epochs_gen(epochs, inverse_operator, lambda2, method, label, nave, pick_ori, prepared, method_params, use_cps, verbose) 1162 logger.info('Picked %d channels from the data' % len(sel)) 1163 logger.info('Computing inverse...') -> 1164 K, noise_norm, vertno, source_nn = _assemble_kernel( 1165 inv, label, method, pick_ori, use_cps) 1167 tstep = 1.0 / epochs.info['sfreq'] 1168 tmin = epochs.times[0] File :12, in _assemble_kernel(inv, label, method, pick_ori, use_cps, verbose) File ~/anaconda3/envs/eegenv/lib/python3.9/site-packages/mne/minimum_norm/inverse.py:733, in _assemble_kernel(inv, label, method, pick_ori, use_cps, verbose) 730 source_nn = inv['source_nn'] 732 if label is not None: --> 733 vertno, src_sel = label_src_vertno_sel(label, src) 735 if method not in ["MNE", "eLORETA"]: 736 noise_norm = noise_norm[src_sel] TypeError: cannot unpack non-iterable Exception object ``` ---
**Author:** ![georgekenefati](https://avatars.discourse-cdn.com/v4/letter/g/34f0e0/32.png) [@georgekenefati](https://mne.discourse.group/u/georgekenefati)\ **Post date:** [May 19, 2023, 7:44pm UTC](https://mne.discourse.group/t/cannot-select-labels-while-applying-inverse-operator-to-epochs-object/6923/2 "2023-05-19T19:44:02Z")
I decided I do not want to use stc.save() since I would have to save each epoch individually. I’d rather just work with the object from memory. I will leave up the question anyway in case a solution is required. Thanks, George ---
**Author:** ![TijmenWB](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/tijmenwb/32/2665_2.png) [@TijmenWB](https://mne.discourse.group/u/TijmenWB)\ **Post date:** [May 22, 2023, 3:27pm UTC](https://mne.discourse.group/t/cannot-select-labels-while-applying-inverse-operator-to-epochs-object/6923/3 "2023-05-22T15:27:26Z")
I could be entirely wrong here, but isn’t what you want to do selected\_labels[0][i] in the for loop as you put the labels object into a list?