def test_make_regressor_3():
""" test the generated regressor
"""
condition = ([1, 20, 36.5], [2, 2, 2], [1, 1, 1])
frame_times = np.linspace(0, 138, 70)
hrf_model = 'fir'
reg, reg_names = compute_regressor(condition, hrf_model, frame_times,
fir_delays=np.arange(4))
assert_array_equal(np.sum(reg, 0), np.array([3, 3, 3, 3]))
assert len(reg_names) == 4
reg_, reg_names_ = compute_regressor(condition, hrf_model, frame_times,
fir_delays=np.arange(4),
oversampling=50.)
assert_array_equal(reg, reg_)
def test_design_warnings():
"""
test that warnings are correctly raised upon weird design specification
"""
condition = ([-25, 20, 36.5], [0, 0, 0], [1, 1, 1])
frame_times = np.linspace(0, 69, 70)
hrf_model = 'spm'
with warnings.catch_warnings(record=True):
warnings.simplefilter("always")
with pytest.warns(UserWarning):
compute_regressor(condition, hrf_model, frame_times)
condition = ([-25, -25, 36.5], [0, 0, 0], [1, 1, 1])
with warnings.catch_warnings(record=True):
warnings.simplefilter("always")
with pytest.warns(UserWarning):
compute_regressor(condition, hrf_model, frame_times)
def convolveevents(evtable,
epi,
*,
hrf_model='spm',
target_col='stim_id',
regressors=None,
**kwarg):
"""return a convolved design matrix for the design in pd.DataFrame-like evtable,
using the meta data in nibabel.Nifti1Image-like epi to deduce tr and nvol."""
if not "amplitude" in evtable:
LOGGER.info("no amplitude field in evtable, creating")
evtable = evtable.assign(amplitude=1)
if regressors is None:
LOGGER.info("no regressors input, using unique entries in target_col")
regressors = evtable[target_col].unique()
regressors = np.sort(regressors[np.isnan(regressors) == False])
tr = epi.header.get_zooms()[-1]
nvol = epi.shape[-1]
frametimes = np.arange(0, nvol * tr, tr)
convolved = []
for thisreg in regressors:
regtable = evtable.loc[evtable[target_col] == thisreg]
vals = regtable[['onset', 'duration', 'amplitude']].values.T
convolved.append(
hrf.compute_regressor(vals, hrf_model, frametimes, **kwarg)[0])
return np.concatenate(convolved, axis=1)
def get_bold_signal(self, exp, amplitudes, hrf_model, fmri_gain=1):
'''To get the response vector'''
# # To get the stimuli signal within the frame_times framework
# stim = np.zeros_like(self.frame_times) # Contains amplitude of the stimulus in the frame_times space
# for k, idx in idx_stimuli_within_frames:
# stim[idx] = amplitudes[k]
# Build experimental condition vector
exp_condition = np.array((exp.stimulus_onsets, exp.stimulus_durations, amplitudes[:exp.n_stimuli]))\
.reshape(3, exp.n_stimuli)
signal, name = hemodynamic_models.compute_regressor(exp_condition,
hrf_model,
self.frame_times,
con_id='main',
oversampling=1)
# Amplify the signal
signal = fmri_gain * signal
# Take the signal only at the scan values
scan_signal = np.zeros_like(self.scan_times)
for k, idx in enumerate(self.idx_scans_within_frames):
scan_signal[k] = signal[idx, 0]
return signal, scan_signal, name
def test_make_regressor_1():
""" test the generated regressor
"""
condition = ([1, 20, 36.5], [2, 2, 2], [1, 1, 1])
frame_times = np.linspace(0, 69, 70)
hrf_model = "spm"
reg, reg_names = compute_regressor(condition, hrf_model, frame_times)
assert_almost_equal(reg.sum(), 6, 1)
assert_equal(reg_names[0], "cond")
def test_make_regressor_2():
""" test the generated regressor
"""
condition = ([1, 20, 36.5], [0, 0, 0], [1, 1, 1])
frame_times = np.linspace(0, 69, 70)
hrf_model = 'spm'
reg, reg_names = compute_regressor(condition, hrf_model, frame_times)
assert_almost_equal(reg.sum() * 50, 3, 1)
assert_equal(reg_names[0], 'cond')
def test_make_regressor_2():
""" test the generated regressor
"""
condition = ([1, 20, 36.5], [0, 0, 0], [1, 1, 1])
frame_times = np.linspace(0, 69, 70)
hrf_model = 'spm'
reg, reg_names = compute_regressor(condition, hrf_model, frame_times)
assert_almost_equal(reg.sum() * 50, 3, 1)
assert_equal(reg_names[0], 'cond')
def test_make_regressor_3():
""" test the generated regressor
"""
condition = ([1, 20, 36.5], [0, 0, 0], [1, 1, 1])
frame_times = np.linspace(0, 138, 70)
hrf_model = "fir"
reg, reg_names = compute_regressor(condition, hrf_model, frame_times, fir_delays=np.arange(4))
assert_array_equal(np.unique(reg), np.array([0, 1]))
assert_array_equal(np.sum(reg, 0), np.array([3, 3, 3, 3]))
assert_equal(len(reg_names), 4)
def test_make_regressor_3():
""" test the generated regressor
"""
condition = ([1, 20, 36.5], [0, 0, 0], [1, 1, 1])
frame_times = np.linspace(0, 138, 70)
hrf_model = 'fir'
reg, reg_names = compute_regressor(condition,
hrf_model,
frame_times,
fir_delays=np.arange(4))
assert_array_equal(np.unique(reg), np.array([0, 1]))
assert_array_equal(np.sum(reg, 0), np.array([3, 3, 3, 3]))
assert_equal(len(reg_names), 4)
def process_raw_features(run, tr, nscans):
# compute convolution of raw_features with hrf kernel
df = pd.read_csv(run)
result = []
count = 0
raw_features_columns = [
col for col in df.columns if col not in ['offsets', 'duration']
]
for col in raw_features_columns:
conditions = np.vstack((df.offsets, df.duration, df[col]))
tmp = compute_regressor(exp_condition=conditions,
hrf_model='spm',
frame_times=np.arange(0.0, nscans * tr, tr),
oversampling=10)
result.append(pd.DataFrame(tmp[0], columns=[col]))
count += 1
return pd.concat(result, axis=1)
def onset2reg(df, nscans, tr):
""" df : pandas dataframe with columnes onset and amplitude, and, optionnaly, duration
nscans: number of scans
tr : sampling period of scanning"""
n_events = len(df)
onsets = df.onset
amplitudes = df.amplitude
if 'duration' in df.columns: # optionaly, use "duration"
durations = df.duration
else:
durations = np.zeros(n_events)
conditions = np.vstack((onsets, durations, amplitudes))
x = compute_regressor(exp_condition=conditions,
hrf_model="spm",
frame_times=np.arange(0.0, nscans * tr, tr),
oversampling=10)
return pd.DataFrame(x[0], columns=['hrf'])
def __init__(self, name, frame_times, onset, *, duration=None,
modulation=None):
'''
Args:
name (str): Name of the regressor.
frame_times (np.ndarray of shape (n_frames,)):
The timing of acquisition of the scans in seconds.
onset (array-like):
Specifies the start time of each event in seconds.
duration (array-like, optional):
Duration of each event in seconds. Defaults duration is set to 0
(impulse function).
modulation (array-like, optional):
Parametric modulation of event amplitude. Before convolution
regressor is demeaned.
'''
if not isinstance(frame_times, np.ndarray) or frame_times.ndim != 1:
msg = 'frame_times should be np.ndarray of shape (n_frames, )'
raise TypeError(msg)
self._name = name
self._frame_times = frame_times
n_events = len(onset)
if duration is None:
duration = np.zeros(n_events)
if modulation is None or (len(modulation) > 1
and np.all(np.array(modulation) == modulation[0])):
modulation = np.ones(n_events)
elif len(modulation) > 1:
modulation = np.array(modulation)
modulation = modulation - np.mean(modulation)
self._values, _ = hemodynamic_models.compute_regressor(
exp_condition=np.vstack((onset, duration, modulation)),
hrf_model='spm',
frame_times=frame_times
)
def convolve(signal, t_r=2, oversampling=50, hrf_model='spm'):
'''Convolve signal with hemodynamic response function.
Performs signal convolution with requested hrf model. This function wraps around nistats
compute_regressor function usually used for creating task-based regressors. The trick is to
define neural regressor as a sequence of equally spaced (with the gap of 1TR) and modulated
'task events'. Event amplitude modulation corresponds to neural signal amplitude at a given
timepoint.
Args:
signal (iterable):
Neural signal.
t_r (float):
Repetition time in seconds.
oversampling (int, optional):
Convolution upsampling rate.
hrf_model (str, optional):
Hemodynamic response function type. See the documentation of compute regressor function
from nistats.hemodynamic_models for more details.
Returns:
Convolved neural signal in BOLD space.
'''
n_volumes = len(signal)
frame_times = np.arange(0, n_volumes * t_r, t_r)
onsets = np.zeros((3, n_volumes))
for vol, amplitude in enumerate(signal):
onsets[:, vol] = (vol * t_r, 0, amplitude)
signal_bold = hemodynamic_models.compute_regressor(
onsets,
hrf_model=hrf_model,
frame_times=frame_times,
oversampling=oversampling,
fir_delays=None)[0].ravel()
return signal_bold
def compute_regressor(self, dataframe, offset_type, duration_type,
run_index):
""" Compute the convolution with an hrf for each column of the dataframe.
Arguments:
- dataframes: pd.DataFrame
- offset_type: str
- duration_type: str
- run_index: str
Returns:
- matrix: np.array
"""
regressors = []
dataframe = dataframe.dropna(axis=0)
representations = [col for col in dataframe.columns]
offsets = fetch_offsets(offset_type, run_index, self.offset_path,
self.language)
duration = fetch_duration(duration_type,
run_index,
self.duration_path,
default_size=len(dataframe))
offsets += self.temporal_shifting # shift offsets by 'temporal_shifting' seconds
for col in representations:
conditions = np.vstack((offsets, duration, dataframe[col]))
signal, name = compute_regressor(
exp_condition=conditions,
hrf_model=self.hrf,
frame_times=np.arange(0.0, self.nscans[run_index] * self.tr,
self.tr),
oversampling=self.oversampling)
col = str(col)
regressors.append(
pd.DataFrame(signal,
columns=[col] +
[col + '_' + item for item in name[1:]]))
matrix = pd.concat(regressors, axis=1).values
return matrix
stim = np.zeros_like(frame_times)
for k in range(n_events):
stim[(frame_times > onset[k]) *
(frame_times <= onset[k] + duration[k])] = amplitude[k]
exp_condition = np.array((onset, duration, amplitude)).reshape(3, n_events)
hrf_models = [None, 'spm', 'glover + derivative']
#########################################################################
# sample the hrf
fig = plt.figure(figsize=(9, 4))
for i, hrf_model in enumerate(hrf_models):
signal, name = hemodynamic_models.compute_regressor(exp_condition,
hrf_model,
frame_times,
con_id='main',
oversampling=16,
fir_delays=np.array(
[1., 2.]))
plt.subplot(1, 3, i + 1)
# plt.fill(frame_times, stim, 'k', alpha=.5, label='stimulus')
for j in range(signal.shape[1]):
plt.plot(frame_times, signal.T[j], label=name[j])
plt.xlabel('time (s)')
#plt.legend(loc=1)
plt.title(hrf_model)
plt.subplots_adjust(bottom=.12)
plt.savefig('output/figures/example_hrf.png', bbox_inches='tight')
# ----------------------------------
#
# Let's quickly plot this file:
frame_times = np.linspace(0, 30, 61)
onset, amplitude, duration = 0., 1., 1.
stim = np.zeros_like(frame_times)
stim[(frame_times > onset) * (frame_times <= onset + duration)] = amplitude
exp_condition = np.array((onset, duration, amplitude)).reshape(3, 1)
hrf_models = [None, 'glover + derivative', 'glover + derivative + dispersion']
#########################################################################
# sample the hrf
fig = plt.figure(figsize=(9, 4))
for i, hrf_model in enumerate(hrf_models):
signal, name = hemodynamic_models.compute_regressor(exp_condition,
hrf_model,
frame_times,
con_id='main',
oversampling=16)
plt.subplot(1, 3, i + 1)
plt.fill(frame_times, stim, 'k', alpha=.5, label='stimulus')
for j in range(signal.shape[1]):
plt.plot(frame_times, signal.T[j], label=name[j])
plt.xlabel('time (s)')
plt.legend(loc=1)
plt.title(hrf_model)
plt.subplots_adjust(bottom=.12)
plt.show()
import matplotlib.pyplot as plt
from nistats import hemodynamic_models
# parameters
frame_times = np.linspace(0, 30, 61)
onset, amplitude, duration = 0., 1., 1.
stim = np.zeros_like(frame_times)
stim[(frame_times > onset) * (frame_times <= onset + duration)] = amplitude
exp_condition = np.array((onset, duration, amplitude)).reshape(3, 1)
hrf_models = ['glover + derivative', 'glover + derivative + dispersion']
fig = plt.figure(figsize=(9, 4))
# sample the hrf
for i, hrf_model in enumerate(hrf_models):
signal, name = hemodynamic_models.compute_regressor(
exp_condition, hrf_model, frame_times, con_id='main',
oversampling=16)
plt.subplot(1, 2, i + 1)
plt.fill(frame_times, stim, 'k', alpha=.5, label='stimulus')
for j in range(signal.shape[1]):
plt.plot(frame_times, signal.T[j], label=name[j])
plt.xlabel('time (s)')
plt.legend(loc=1)
plt.title(hrf_model)
plt.subplots_adjust(bottom=.12)
fig.show()