Ejemplo n.º 1
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# desired baseline length, and 0 for tmax_plot.
# Note, if using baseline data, the averaged evoked response in the baseline
# period should be flat.
noise_covs = []
for (l_freq, h_freq) in freq_bins:
    raw_band = raw_noise.copy()
    raw_band.filter(l_freq, h_freq, picks=epochs.picks, method='iir', n_jobs=1)
    epochs_band = mne.Epochs(raw_band, epochs_noise.events, event_id,
                             tmin=tmin_plot, tmax=tmax_plot, baseline=None,
                             picks=epochs.picks, proj=True)

    noise_cov = compute_covariance(epochs_band)
    noise_cov = mne.cov.regularize(noise_cov, epochs_band.info, mag=noise_reg,
                                   grad=noise_reg, eeg=noise_reg, proj=True)
    noise_covs.append(noise_cov)
    del raw_band  # to save memory

# Computing LCMV solutions for time-frequency windows in a label in source
# space for faster computation, use label=None for full solution
stcs = tf_lcmv(epochs, forward, noise_covs, tmin, tmax, tstep, win_lengths,
               freq_bins=freq_bins, subtract_evoked=subtract_evoked,
               reg=data_reg, label=label)

# Plotting source spectrogram for source with maximum activity.
# Note that tmin and tmax are set to display a time range that is smaller than
# the one for which beamforming estimates were calculated. This ensures that
# all time bins shown are a result of smoothing across an identical number of
# time windows.
plot_source_spectrogram(stcs, freq_bins, tmin=tmin_plot, tmax=tmax_plot,
                        source_index=None, colorbar=True)
Ejemplo n.º 2
0
                             tmax=tmax,
                             picks=epochs.picks,
                             proj=True)

    noise_cov = compute_covariance(epochs_band)
    noise_cov = mne.cov.regularize(noise_cov,
                                   epochs_band.info,
                                   mag=noise_reg,
                                   grad=noise_reg,
                                   eeg=noise_reg,
                                   proj=True)
    noise_covs.append(noise_cov)
    del raw_band  # to save memory

# Computing LCMV solutions for time-frequency windows in a label in source
# space for faster computation, use label=None for full solution
stcs = tf_lcmv(epochs,
               forward,
               noise_covs,
               tmin,
               tmax,
               tstep,
               win_lengths,
               freq_bins=freq_bins,
               subtract_evoked=subtract_evoked,
               reg=data_reg,
               label=label)

# Plotting source spectrogram for source with maximum activity
plot_source_spectrogram(stcs, freq_bins, source_index=None, colorbar=True)
Ejemplo n.º 3
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def test_tf_lcmv():
    """Test TF beamforming based on LCMV
    """
    fname_raw = op.join(data_path, 'MEG', 'sample',
                        'sample_audvis_filt-0-40_raw.fif')
    label = mne.read_label(fname_label)
    events = mne.read_events(fname_event)
    raw = mne.io.Raw(fname_raw, preload=True)
    forward = mne.read_forward_solution(fname_fwd)

    event_id, tmin, tmax = 1, -0.2, 0.2

    # Setup for reading the raw data
    raw.info['bads'] = ['MEG 2443', 'EEG 053']  # 2 bads channels

    # Set up pick list: MEG - bad channels
    left_temporal_channels = mne.read_selection('Left-temporal')
    picks = mne.pick_types(raw.info,
                           meg=True,
                           eeg=False,
                           stim=True,
                           eog=True,
                           exclude='bads',
                           selection=left_temporal_channels)

    # Read epochs
    epochs = mne.Epochs(raw,
                        events,
                        event_id,
                        tmin,
                        tmax,
                        proj=True,
                        picks=picks,
                        baseline=None,
                        preload=False,
                        reject=dict(grad=4000e-13, mag=4e-12, eog=150e-6))
    epochs.drop_bad_epochs()

    freq_bins = [(4, 12), (15, 40)]
    time_windows = [(-0.1, 0.1), (0.0, 0.2)]
    win_lengths = [0.2, 0.2]
    tstep = 0.1
    reg = 0.05

    source_power = []
    noise_covs = []
    for (l_freq, h_freq), win_length in zip(freq_bins, win_lengths):
        raw_band = raw.copy()
        raw_band.filter(l_freq, h_freq, method='iir', n_jobs=1, picks=picks)
        epochs_band = mne.Epochs(raw_band,
                                 epochs.events,
                                 epochs.event_id,
                                 tmin=tmin,
                                 tmax=tmax,
                                 baseline=None,
                                 proj=True)
        with warnings.catch_warnings(record=True):  # not enough samples
            noise_cov = compute_covariance(epochs_band,
                                           tmin=tmin,
                                           tmax=tmin + win_length)
        noise_cov = mne.cov.regularize(noise_cov,
                                       epochs_band.info,
                                       mag=reg,
                                       grad=reg,
                                       eeg=reg,
                                       proj=True)
        noise_covs.append(noise_cov)
        del raw_band  # to save memory

        # Manually calculating source power in on frequency band and several
        # time windows to compare to tf_lcmv results and test overlapping
        if (l_freq, h_freq) == freq_bins[0]:
            for time_window in time_windows:
                with warnings.catch_warnings(record=True):
                    data_cov = compute_covariance(epochs_band,
                                                  tmin=time_window[0],
                                                  tmax=time_window[1])
                stc_source_power = _lcmv_source_power(epochs.info,
                                                      forward,
                                                      noise_cov,
                                                      data_cov,
                                                      reg=reg,
                                                      label=label)
                source_power.append(stc_source_power.data)

    stcs = tf_lcmv(epochs,
                   forward,
                   noise_covs,
                   tmin,
                   tmax,
                   tstep,
                   win_lengths,
                   freq_bins,
                   reg=reg,
                   label=label)

    assert_true(len(stcs) == len(freq_bins))
    assert_true(stcs[0].shape[1] == 4)

    # Averaging all time windows that overlap the time period 0 to 100 ms
    source_power = np.mean(source_power, axis=0)

    # Selecting the first frequency bin in tf_lcmv results
    stc = stcs[0]

    # Comparing tf_lcmv results with _lcmv_source_power results
    assert_array_almost_equal(stc.data[:, 2], source_power[:, 0])

    # Test if using unsupported max-power orientation is detected
    assert_raises(ValueError,
                  tf_lcmv,
                  epochs,
                  forward,
                  noise_covs,
                  tmin,
                  tmax,
                  tstep,
                  win_lengths,
                  freq_bins=freq_bins,
                  pick_ori='max-power')

    # Test if incorrect number of noise CSDs is detected
    # Test if incorrect number of noise covariances is detected
    assert_raises(ValueError, tf_lcmv, epochs, forward, [noise_covs[0]], tmin,
                  tmax, tstep, win_lengths, freq_bins)

    # Test if freq_bins and win_lengths incompatibility is detected
    assert_raises(ValueError,
                  tf_lcmv,
                  epochs,
                  forward,
                  noise_covs,
                  tmin,
                  tmax,
                  tstep,
                  win_lengths=[0, 1, 2],
                  freq_bins=freq_bins)

    # Test if time step exceeding window lengths is detected
    assert_raises(ValueError,
                  tf_lcmv,
                  epochs,
                  forward,
                  noise_covs,
                  tmin,
                  tmax,
                  tstep=0.15,
                  win_lengths=[0.2, 0.1],
                  freq_bins=freq_bins)

    # Test correct detection of preloaded epochs objects that do not contain
    # the underlying raw object
    epochs_preloaded = mne.Epochs(raw,
                                  events,
                                  event_id,
                                  tmin,
                                  tmax,
                                  proj=True,
                                  baseline=(None, 0),
                                  preload=True)
    assert_raises(ValueError, tf_lcmv, epochs_preloaded, forward, noise_covs,
                  tmin, tmax, tstep, win_lengths, freq_bins)

    with warnings.catch_warnings(record=True):  # not enough samples
        # Pass only one epoch to test if subtracting evoked
        # responses yields zeros
        stcs = tf_lcmv(epochs[0],
                       forward,
                       noise_covs,
                       tmin,
                       tmax,
                       tstep,
                       win_lengths,
                       freq_bins,
                       subtract_evoked=True,
                       reg=reg,
                       label=label)

    assert_array_almost_equal(stcs[0].data, np.zeros_like(stcs[0].data))
Ejemplo n.º 4
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def test_tf_lcmv():
    """Test TF beamforming based on LCMV
    """
    fname_raw = op.join(data_path, 'MEG', 'sample',
                        'sample_audvis_filt-0-40_raw.fif')
    label = mne.read_label(fname_label)
    events = mne.read_events(fname_event)
    raw = mne.fiff.Raw(fname_raw, preload=True)
    forward = mne.read_forward_solution(fname_fwd)

    event_id, tmin, tmax = 1, -0.2, 0.2

    # Setup for reading the raw data
    raw.info['bads'] = ['MEG 2443', 'EEG 053']  # 2 bads channels

    # Set up pick list: MEG - bad channels
    left_temporal_channels = mne.read_selection('Left-temporal')
    picks = mne.fiff.pick_types(raw.info, meg=True, eeg=False,
                                stim=True, eog=True, exclude='bads',
                                selection=left_temporal_channels)

    # Read epochs
    epochs = mne.Epochs(raw, events, event_id, tmin, tmax, proj=True,
                        picks=picks, baseline=(None, 0),
                        preload=False,
                        reject=dict(grad=4000e-13, mag=4e-12, eog=150e-6))
    epochs.drop_bad_epochs()

    freq_bins = [(4, 12), (15, 40)]
    time_windows = [(-0.1, 0.1), (0.0, 0.2)]
    win_lengths = [0.2, 0.2]
    tstep = 0.1
    reg = 0.05

    source_power = []
    noise_covs = []
    for (l_freq, h_freq), win_length in zip(freq_bins, win_lengths):
        raw_band = raw.copy()
        raw_band.filter(l_freq, h_freq, method='iir', n_jobs=1, picks=picks)
        epochs_band = mne.Epochs(raw_band, epochs.events, epochs.event_id,
                                 tmin=tmin, tmax=tmax, proj=True)
        with warnings.catch_warnings(record=True):  # not enough samples
            noise_cov = compute_covariance(epochs_band, tmin=tmin, tmax=tmin +
                                           win_length)
        noise_cov = mne.cov.regularize(noise_cov, epochs_band.info, mag=reg,
                                       grad=reg, eeg=reg, proj=True)
        noise_covs.append(noise_cov)
        del raw_band  # to save memory

        # Manually calculating source power in on frequency band and several
        # time windows to compare to tf_lcmv results and test overlapping
        if (l_freq, h_freq) == freq_bins[0]:
            for time_window in time_windows:
                with warnings.catch_warnings(record=True):
                    data_cov = compute_covariance(epochs_band,
                                                  tmin=time_window[0],
                                                  tmax=time_window[1])
                stc_source_power = _lcmv_source_power(epochs.info, forward,
                                                      noise_cov, data_cov,
                                                      reg=reg, label=label)
                source_power.append(stc_source_power.data)

    stcs = tf_lcmv(epochs, forward, noise_covs, tmin, tmax, tstep, win_lengths,
                   freq_bins, reg=reg, label=label)

    assert_true(len(stcs) == len(freq_bins))
    assert_true(stcs[0].shape[1] == 4)

    # Averaging all time windows that overlap the time period 0 to 100 ms
    source_power = np.mean(source_power, axis=0)

    # Selecting the first frequency bin in tf_lcmv results
    stc = stcs[0]

    # Comparing tf_lcmv results with _lcmv_source_power results
    assert_array_almost_equal(stc.data[:, 2], source_power[:, 0])

    # Test if using unsupported max-power orientation is detected
    assert_raises(ValueError, tf_lcmv, epochs, forward, noise_covs, tmin, tmax,
                  tstep, win_lengths, freq_bins=freq_bins,
                  pick_ori='max-power')

    # Test if incorrect number of noise CSDs is detected
    # Test if incorrect number of noise covariances is detected
    assert_raises(ValueError, tf_lcmv, epochs, forward, [noise_covs[0]], tmin,
                  tmax, tstep, win_lengths, freq_bins)

    # Test if freq_bins and win_lengths incompatibility is detected
    assert_raises(ValueError, tf_lcmv, epochs, forward, noise_covs, tmin, tmax,
                  tstep, win_lengths=[0, 1, 2], freq_bins=freq_bins)

    # Test if time step exceeding window lengths is detected
    assert_raises(ValueError, tf_lcmv, epochs, forward, noise_covs, tmin, tmax,
                  tstep=0.15, win_lengths=[0.2, 0.1], freq_bins=freq_bins)

    # Test correct detection of preloaded epochs objects that do not contain
    # the underlying raw object
    epochs_preloaded = mne.Epochs(raw, events, event_id, tmin, tmax, proj=True,
                                  baseline=(None, 0), preload=True)
    assert_raises(ValueError, tf_lcmv, epochs_preloaded, forward, noise_covs,
                  tmin, tmax, tstep, win_lengths, freq_bins)

    with warnings.catch_warnings(record=True):  # not enough samples
        # Pass only one epoch to test if subtracting evoked
        # responses yields zeros
        stcs = tf_lcmv(epochs[0], forward, noise_covs, tmin, tmax, tstep,
                       win_lengths, freq_bins, subtract_evoked=True, reg=reg,
                       label=label)

    assert_array_almost_equal(stcs[0].data, np.zeros_like(stcs[0].data))
Ejemplo n.º 5
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def test_tf_lcmv():
    """Test TF beamforming based on LCMV."""
    label = mne.read_label(fname_label)
    events = mne.read_events(fname_event)
    raw = mne.io.read_raw_fif(fname_raw, preload=True)
    forward = mne.read_forward_solution(fname_fwd)

    event_id, tmin, tmax = 1, -0.2, 0.2

    # Setup for reading the raw data
    raw.info['bads'] = ['MEG 2443', 'EEG 053']  # 2 bads channels

    # Set up pick list: MEG - bad channels
    left_temporal_channels = mne.read_selection('Left-temporal')
    picks = mne.pick_types(raw.info, selection=left_temporal_channels)
    picks = picks[::4]  # decimate for speed
    raw.pick_channels([raw.ch_names[ii] for ii in picks])
    raw.info.normalize_proj()  # avoid projection warnings
    del picks

    # Read epochs
    epochs = mne.Epochs(raw,
                        events,
                        event_id,
                        tmin,
                        tmax,
                        proj=True,
                        baseline=None,
                        preload=False,
                        reject=reject)
    epochs.load_data()

    freq_bins = [(4, 12), (15, 40)]
    time_windows = [(-0.1, 0.1), (0.0, 0.2)]
    win_lengths = [0.2, 0.2]
    tstep = 0.1
    reg = 0.05

    source_power = []
    noise_covs = []
    for (l_freq, h_freq), win_length in zip(freq_bins, win_lengths):
        raw_band = raw.copy()
        raw_band.filter(l_freq,
                        h_freq,
                        method='iir',
                        n_jobs=1,
                        iir_params=dict(output='ba'))
        epochs_band = mne.Epochs(raw_band,
                                 epochs.events,
                                 epochs.event_id,
                                 tmin=tmin,
                                 tmax=tmax,
                                 baseline=None,
                                 proj=True)
        with warnings.catch_warnings(record=True):  # not enough samples
            noise_cov = mne.compute_covariance(epochs_band,
                                               tmin=tmin,
                                               tmax=tmin + win_length)
        noise_cov = mne.cov.regularize(noise_cov,
                                       epochs_band.info,
                                       mag=reg,
                                       grad=reg,
                                       eeg=reg,
                                       proj=True)
        noise_covs.append(noise_cov)
        del raw_band  # to save memory

        # Manually calculating source power in on frequency band and several
        # time windows to compare to tf_lcmv results and test overlapping
        if (l_freq, h_freq) == freq_bins[0]:
            for time_window in time_windows:
                with warnings.catch_warnings(record=True):  # bad samples
                    data_cov = mne.compute_covariance(epochs_band,
                                                      tmin=time_window[0],
                                                      tmax=time_window[1])
                with warnings.catch_warnings(record=True):  # bad proj
                    stc_source_power = _lcmv_source_power(
                        epochs.info,
                        forward,
                        noise_cov,
                        data_cov,
                        reg=reg,
                        label=label,
                        weight_norm='unit-noise-gain')
                source_power.append(stc_source_power.data)

    pytest.raises(ValueError,
                  tf_lcmv,
                  epochs,
                  forward,
                  noise_covs,
                  tmin,
                  tmax,
                  tstep,
                  win_lengths,
                  freq_bins,
                  reg=reg,
                  label=label)
    stcs = tf_lcmv(epochs,
                   forward,
                   noise_covs,
                   tmin,
                   tmax,
                   tstep,
                   win_lengths,
                   freq_bins,
                   reg=reg,
                   label=label,
                   raw=raw)

    assert (len(stcs) == len(freq_bins))
    assert (stcs[0].shape[1] == 4)

    # Averaging all time windows that overlap the time period 0 to 100 ms
    source_power = np.mean(source_power, axis=0)

    # Selecting the first frequency bin in tf_lcmv results
    stc = stcs[0]

    # Comparing tf_lcmv results with _lcmv_source_power results
    assert_array_almost_equal(stc.data[:, 2], source_power[:, 0])

    # Test if using unsupported max-power orientation is detected
    pytest.raises(ValueError,
                  tf_lcmv,
                  epochs,
                  forward,
                  noise_covs,
                  tmin,
                  tmax,
                  tstep,
                  win_lengths,
                  freq_bins=freq_bins,
                  pick_ori='max-power')

    # Test if incorrect number of noise CSDs is detected
    # Test if incorrect number of noise covariances is detected
    pytest.raises(ValueError, tf_lcmv, epochs, forward, [noise_covs[0]], tmin,
                  tmax, tstep, win_lengths, freq_bins)

    # Test if freq_bins and win_lengths incompatibility is detected
    pytest.raises(ValueError,
                  tf_lcmv,
                  epochs,
                  forward,
                  noise_covs,
                  tmin,
                  tmax,
                  tstep,
                  win_lengths=[0, 1, 2],
                  freq_bins=freq_bins)

    # Test if time step exceeding window lengths is detected
    pytest.raises(ValueError,
                  tf_lcmv,
                  epochs,
                  forward,
                  noise_covs,
                  tmin,
                  tmax,
                  tstep=0.15,
                  win_lengths=[0.2, 0.1],
                  freq_bins=freq_bins)

    # Test if missing of noise covariance matrix is detected when more than
    # one channel type is present in the data
    pytest.raises(ValueError,
                  tf_lcmv,
                  epochs,
                  forward,
                  noise_covs=None,
                  tmin=tmin,
                  tmax=tmax,
                  tstep=tstep,
                  win_lengths=win_lengths,
                  freq_bins=freq_bins)

    # Test if unsupported weight normalization specification is detected
    pytest.raises(ValueError,
                  tf_lcmv,
                  epochs,
                  forward,
                  noise_covs,
                  tmin,
                  tmax,
                  tstep,
                  win_lengths,
                  freq_bins,
                  weight_norm='nai')

    # Test unsupported pick_ori (vector not supported here)
    with pytest.raises(ValueError, match='pick_ori must be one of'):
        tf_lcmv(epochs,
                forward,
                noise_covs,
                tmin,
                tmax,
                tstep,
                win_lengths,
                freq_bins,
                pick_ori='vector')
    # Test correct detection of preloaded epochs objects that do not contain
    # the underlying raw object
    epochs_preloaded = mne.Epochs(raw,
                                  events,
                                  event_id,
                                  tmin,
                                  tmax,
                                  proj=True,
                                  baseline=(None, 0),
                                  preload=True)
    epochs_preloaded._raw = None
    with warnings.catch_warnings(record=True):  # not enough samples
        pytest.raises(ValueError, tf_lcmv, epochs_preloaded, forward,
                      noise_covs, tmin, tmax, tstep, win_lengths, freq_bins)

    with warnings.catch_warnings(record=True):  # not enough samples
        # Pass only one epoch to test if subtracting evoked
        # responses yields zeros
        stcs = tf_lcmv(epochs[0],
                       forward,
                       noise_covs,
                       tmin,
                       tmax,
                       tstep,
                       win_lengths,
                       freq_bins,
                       subtract_evoked=True,
                       reg=reg,
                       label=label,
                       raw=raw)

    assert_array_almost_equal(stcs[0].data, np.zeros_like(stcs[0].data))
Ejemplo n.º 6
0
def test_tf_lcmv():
    """Test TF beamforming based on LCMV."""
    label = mne.read_label(fname_label)
    events = mne.read_events(fname_event)
    raw = mne.io.read_raw_fif(fname_raw, preload=True)
    forward = mne.read_forward_solution(fname_fwd)

    event_id, tmin, tmax = 1, -0.2, 0.2

    # Setup for reading the raw data
    raw.info['bads'] = ['MEG 2443', 'EEG 053']  # 2 bads channels

    # Set up pick list: MEG - bad channels
    left_temporal_channels = mne.read_selection('Left-temporal')
    picks = mne.pick_types(raw.info, selection=left_temporal_channels)
    picks = picks[::2]  # decimate for speed
    raw.pick_channels([raw.ch_names[ii] for ii in picks])
    raw.info.normalize_proj()  # avoid projection warnings
    del picks

    # Read epochs
    epochs = mne.Epochs(raw, events, event_id, tmin, tmax, proj=True,
                        baseline=None, preload=False, reject=reject)
    epochs.load_data()

    freq_bins = [(4, 12), (15, 40)]
    time_windows = [(-0.1, 0.1), (0.0, 0.2)]
    win_lengths = [0.2, 0.2]
    tstep = 0.1
    reg = 0.05

    source_power = []
    noise_covs = []
    for (l_freq, h_freq), win_length in zip(freq_bins, win_lengths):
        raw_band = raw.copy()
        raw_band.filter(l_freq, h_freq, method='iir', n_jobs=1,
                        iir_params=dict(output='ba'))
        epochs_band = mne.Epochs(
            raw_band, epochs.events, epochs.event_id, tmin=tmin, tmax=tmax,
            baseline=None, proj=True)
        noise_cov = mne.compute_covariance(
            epochs_band, tmin=tmin, tmax=tmin + win_length)
        noise_cov = mne.cov.regularize(
            noise_cov, epochs_band.info, mag=reg, grad=reg, eeg=reg,
            proj=True)
        noise_covs.append(noise_cov)
        del raw_band  # to save memory

        # Manually calculating source power in on frequency band and several
        # time windows to compare to tf_lcmv results and test overlapping
        if (l_freq, h_freq) == freq_bins[0]:
            for time_window in time_windows:
                data_cov = mne.compute_covariance(
                    epochs_band, tmin=time_window[0], tmax=time_window[1])
                stc_source_power = _lcmv_source_power(
                    epochs.info, forward, noise_cov, data_cov,
                    reg=reg, label=label, weight_norm='unit-noise-gain')
                source_power.append(stc_source_power.data)

    pytest.raises(ValueError, tf_lcmv, epochs, forward, noise_covs, tmin, tmax,
                  tstep, win_lengths, freq_bins, reg=reg, label=label)
    stcs = tf_lcmv(epochs, forward, noise_covs, tmin, tmax, tstep,
                   win_lengths, freq_bins, reg=reg, label=label, raw=raw)

    assert (len(stcs) == len(freq_bins))
    assert (stcs[0].shape[1] == 4)

    # Averaging all time windows that overlap the time period 0 to 100 ms
    source_power = np.mean(source_power, axis=0)

    # Selecting the first frequency bin in tf_lcmv results
    stc = stcs[0]

    # Comparing tf_lcmv results with _lcmv_source_power results
    assert_array_almost_equal(stc.data[:, 2], source_power[:, 0])

    # Test if using unsupported max-power orientation is detected
    pytest.raises(ValueError, tf_lcmv, epochs, forward, noise_covs, tmin, tmax,
                  tstep, win_lengths, freq_bins=freq_bins,
                  pick_ori='max-power')

    # Test if incorrect number of noise CSDs is detected
    # Test if incorrect number of noise covariances is detected
    pytest.raises(ValueError, tf_lcmv, epochs, forward, [noise_covs[0]], tmin,
                  tmax, tstep, win_lengths, freq_bins)

    # Test if freq_bins and win_lengths incompatibility is detected
    pytest.raises(ValueError, tf_lcmv, epochs, forward, noise_covs, tmin, tmax,
                  tstep, win_lengths=[0, 1, 2], freq_bins=freq_bins)

    # Test if time step exceeding window lengths is detected
    pytest.raises(ValueError, tf_lcmv, epochs, forward, noise_covs, tmin, tmax,
                  tstep=0.15, win_lengths=[0.2, 0.1], freq_bins=freq_bins)

    # Test if missing of noise covariance matrix is detected when more than
    # one channel type is present in the data
    pytest.raises(ValueError, tf_lcmv, epochs, forward, noise_covs=None,
                  tmin=tmin, tmax=tmax, tstep=tstep, win_lengths=win_lengths,
                  freq_bins=freq_bins)

    # Test if unsupported weight normalization specification is detected
    pytest.raises(ValueError, tf_lcmv, epochs, forward, noise_covs, tmin, tmax,
                  tstep, win_lengths, freq_bins, weight_norm='nai')

    # Test unsupported pick_ori (vector not supported here)
    with pytest.raises(ValueError, match='pick_ori must be one of'):
        tf_lcmv(epochs, forward, noise_covs, tmin, tmax, tstep, win_lengths,
                freq_bins, pick_ori='vector')
    # Test correct detection of preloaded epochs objects that do not contain
    # the underlying raw object
    epochs_preloaded = mne.Epochs(raw, events, event_id, tmin, tmax, proj=True,
                                  baseline=(None, 0), preload=True)
    epochs_preloaded._raw = None
    pytest.raises(ValueError, tf_lcmv, epochs_preloaded, forward,
                  noise_covs, tmin, tmax, tstep, win_lengths, freq_bins)

    # Pass only one epoch to test if subtracting evoked
    # responses yields zeros
    with pytest.warns(RuntimeWarning,
                      match='Too few samples .* estimate may be unreliable'):
        stcs = tf_lcmv(epochs[0], forward, noise_covs, tmin, tmax, tstep,
                       win_lengths, freq_bins, subtract_evoked=True, reg=reg,
                       label=label, raw=raw)

    assert_array_almost_equal(stcs[0].data, np.zeros_like(stcs[0].data))