def get_nii_data_from_folder(folder, use_verbs=False):
# inside the folder, search only for betasXX.nii files
beta_map_regex = r'betas(\d{2}).nii$'
beta_map_filter = re_filter(beta_map_regex)
beta_files = filter(beta_map_filter, glob.glob(os.path.join(folder, "*")))
beta_files = sorted(beta_files)
# get mask file. It must be in same folder
mask_file = os.path.join(folder, "mask.nii")
#new_folder = '/volatile/thirion/mygit/worddecoding/brain_reading/fmri/vl100318/fmri/' ## ugly
#mask_file = os.path.join(new_folder, "HO_epi.nii")
masker = NiftiMasker(mask_file, smooth=3.)
masker.fit(beta_files[0])
masked_nii_data = [masker.transform(beta_file) for beta_file in beta_files]
# this returns a 3D array with dimensions
# (sessions, trials, voxels)
masked_nii_data = np.array(masked_nii_data)
# return only the useful values: The last 6 are
# drift regressors and are thrown away
masked_nii_data = masked_nii_data[:, :-6, :]
if use_verbs:
return masked_nii_data
else:
# In case we do not want the verbs (default case)
# we need to remove the lines corresponding to verbs
masked_nii_data = masked_nii_data.reshape(-1,
masked_nii_data.shape[-1])
masked_nii_data = masked_nii_data[:, masked_nii_data.std(0) > 0]
_, verbs, _, _, _ = parse_stimuli()
return masked_nii_data[verbs == False]
Simple example of NiftiMasker use
==================================
Here is a simple example of automatic mask computation using the nifti masker.
The mask is computed and visualized.
"""
### Load nyu_rest dataset #####################################################
from nisl import datasets
from nisl.io import NiftiMasker
dataset = datasets.fetch_nyu_rest(n_subjects=1)
### Compute the mask ##########################################################
nifti_masker = NiftiMasker(memory="nisl_cache", memory_level=2)
nifti_masker.fit(dataset.func[0])
mask = nifti_masker.mask_img_.get_data()
### Visualize the mask ########################################################
import pylab as pl
import numpy as np
import nibabel
pl.figure()
pl.axis('off')
pl.imshow(np.rot90(nibabel.load(dataset.func[0]).get_data()[..., 20, 0]),
interpolation='nearest', cmap=pl.cm.gray)
ma = np.ma.masked_equal(mask, False)
pl.imshow(np.rot90(ma[..., 20]), interpolation='nearest', cmap=pl.cm.autumn,
alpha=0.5)
pl.title("Mask")
Simple example of NiftiMasker use
==================================
Here is a simple example of automatic mask computation using the nifti masker.
The mask is computed and visualized.
"""
### Load nyu_rest dataset #####################################################
from nisl import datasets
from nisl.io import NiftiMasker
dataset = datasets.fetch_nyu_rest(n_subjects=1)
### Compute the mask ##########################################################
nifti_masker = NiftiMasker(transpose=True,
memory="nisl_cache", memory_level=2)
nifti_masker.fit(dataset.func[0])
mask = nifti_masker.mask_img_.get_data()
### Visualize the mask ########################################################
import pylab as pl
import numpy as np
import nibabel
pl.figure()
pl.axis('off')
pl.imshow(np.rot90(nibabel.load(dataset.func[0]).get_data()[..., 20, 0]),
interpolation='nearest', cmap=pl.cm.gray)
ma = np.ma.masked_equal(mask, False)
pl.imshow(np.rot90(ma[..., 20]), interpolation='nearest', cmap=pl.cm.autumn,
alpha=0.5)
pl.title("Mask")
### Restrict to faces and houses ############################################## # Keep only data corresponding to face or houses condition_mask = np.logical_or(conditions == 'face', conditions == 'house') X = fmri_data[..., condition_mask] y = y[condition_mask] session = session[condition_mask] conditions = conditions[condition_mask] # We have 2 conditions n_conditions = np.size(np.unique(y)) ### Loading step ############################################################## from nisl.io import NiftiMasker from nibabel import Nifti1Image nifti_masker = NiftiMasker(mask=mask, detrend=True, sessions=session) niimg = Nifti1Image(X, affine) X = nifti_masker.fit_transform(niimg) ### Prediction function ####################################################### ### Define the prediction function to be used. # Here we use a Support Vector Classification, with a linear kernel and C=1 from sklearn.svm import SVC clf = SVC(kernel='linear', C=1.) ### Dimension reduction ####################################################### from sklearn.feature_selection import SelectKBest, f_classif ### Define the dimension reduction to be used.
# For compatibility with numpy 1.3 and scikit-learn 0.12 # "return_inverse" option appeared in numpy 1.4, scikit-learn >= 0.14 supports # text labels. # With scikit-learn >= 0.14, replace this line by: target = labels _, target = sklearn.utils.fixes.unique(labels, return_inverse=True) ### Remove resting state condition ############################################ no_rest_indices = (labels != 'rest') target = target[no_rest_indices] ### Load the mask ############################################################# from nisl.io import NiftiMasker nifti_masker = NiftiMasker(mask=dataset.mask_vt[0]) # We give to the nifti_masker a filename, and retrieve a 2D array ready # for machine learning with scikit-learn fmri_masked = nifti_masker.fit_transform(dataset.func[0]) ### Prediction function ####################################################### # First, we remove rest condition fmri_masked = fmri_masked[no_rest_indices] # Here we use a Support Vector Classification, with a linear kernel and C=1 from sklearn.svm import SVC svc = SVC(kernel='linear', C=1.) # And we run it
# Keep only data corresponding to faces or houses
condition_mask = np.logical_or(conditions == 'face', conditions == 'house')
X = fmri_data[..., condition_mask]
y = y[condition_mask]
session = session[condition_mask]
conditions = conditions[condition_mask]
# We have 2 conditions
n_conditions = np.size(np.unique(y))
### Loading step ##############################################################
from nisl.io import NiftiMasker
from nibabel import Nifti1Image
nifti_masker = NiftiMasker(mask=mask,
sessions=session,
smooth=4,
memory="nisl_cache",
memory_level=1)
niimg = Nifti1Image(X, affine)
X = nifti_masker.fit_transform(niimg)
### Prediction function #######################################################
### Define the prediction function to be used.
# Here we use a Support Vector Classification, with a linear kernel and C=1
from sklearn.svm import SVC
clf = SVC(kernel='linear', C=1.)
### Dimension reduction #######################################################
from sklearn.feature_selection import SelectKBest, f_classif
images by mean on the parcellation.
This parcellation may be useful in a supervised learning, see for
instance: `A supervised clustering approach for fMRI-based inference of
brain states <http://hal.inria.fr/inria-00589201>`_, Michel et al,
Pattern Recognition 2011.
"""
### Load nyu_rest dataset #####################################################
from nisl import datasets
from nisl.io import NiftiMasker
dataset = datasets.fetch_nyu_rest(n_subjects=1)
nifti_masker = NiftiMasker()
fmri_masked = nifti_masker.fit_transform(dataset.func[0])
mask = nifti_masker.mask_.get_data()
### Ward ######################################################################
# Compute connectivity matrix: which voxel is connected to which
from sklearn.feature_extraction import image
shape = mask.shape
connectivity = image.grid_to_graph(n_x=shape[0],
n_y=shape[1],
n_z=shape[2],
mask=mask)
# Computing the ward for the first time, this is long...
# Build the mean image because we have no anatomic data
mean_img = fmri_data.mean(axis=-1)
### Restrict to faces and houses ##############################################
condition_mask = np.logical_or(conditions == 'face', conditions == 'house')
X = fmri_data[..., condition_mask]
y = y[condition_mask]
session = session[condition_mask]
conditions = conditions[condition_mask]
### Loading step ##############################################################
from nisl.io import NiftiMasker
from nibabel import Nifti1Image
nifti_masker = NiftiMasker(mask=mask,
sessions=session,
memory='nisl_cache',
memory_level=1)
niimg = Nifti1Image(X, affine)
X_masked = nifti_masker.fit(niimg).transform(niimg)
#X_preprocessed = nifti_masker.inverse_transform(X_masked).get_data()
#X_preprocessed = np.rollaxis(X_preprocessed, axis=-1)
mask = nifti_masker.mask_img_.get_data().astype(np.bool)
### Prepare the masks #########################################################
# Here we will use several masks :
# * mask is the originalmask
# * process_mask is a subset of mask, it contains voxels that should be
# processed (we only keep the slice z = 26 and the back of the brain to speed
# up computation)
process_mask = mask.copy()
process_mask[..., 38:] = False