Note

This page is a reference documentation. It only explains the class signature, and not how to use it. Please refer to the user guide for the big picture.

nilearn.maskers.MultiNiftiMapsMasker

class nilearn.maskers.MultiNiftiMapsMasker(maps_img, mask_img=None, allow_overlap=True, smoothing_fwhm=None, standardize=False, standardize_confounds=True, high_variance_confounds=False, detrend=False, low_pass=None, high_pass=None, t_r=None, dtype=None, resampling_target='data', memory=Memory(location=None), memory_level=0, verbose=0, reports=True, n_jobs=1)

Class for masking of Niimg-like objects.

MultiNiftiMapsMasker is useful when data from overlapping volumes and from different subjects should be extracted (contrary to nilearn.maskers.NiftiMapsMasker).

Note

Inf or NaN present in the given input images are automatically put to zero rather than considered as missing data.

Parameters

maps_img4D niimg-like object

See Input and output: neuroimaging data representation. Set of continuous maps. One representative time course per map is extracted using least square regression.

mask_img3D niimg-like object, optional

See Input and output: neuroimaging data representation. Mask to apply to regions before extracting signals.

allow_overlapbool, optional

If False, an error is raised if the maps overlaps (ie at least two maps have a non-zero value for the same voxel). Default=True.

smoothing_fwhmfloat, optional.

If smoothing_fwhm is not None, it gives the full-width at half maximum in millimeters of the spatial smoothing to apply to the signal.

standardize{False, True, ‘zscore’, ‘psc’}, optional

Strategy to standardize the signal.

• ‘zscore’: the signal is z-scored. Timeseries are shifted to zero mean and scaled to unit variance.

• ‘psc’: Timeseries are shifted to zero mean value and scaled to percent signal change (as compared to original mean signal).

• True : the signal is z-scored. Timeseries are shifted to zero mean and scaled to unit variance.

• False : Do not standardize the data.

Default=False.

standardize_confoundsbool, optional

If set to True, the confounds are z-scored: their mean is put to 0 and their variance to 1 in the time dimension. Default=True.

high_variance_confoundsbool, optional

If True, high variance confounds are computed on provided image with nilearn.image.high_variance_confounds and default parameters and regressed out. Default=False.

detrendbool, optional

Whether to detrend signals or not.

low_passfloat or None, optional

Low cutoff frequency in Hertz. If specified, signals above this frequency will be filtered out. If None, no low-pass filtering will be performed. Default=None.

high_passfloat, optional

High cutoff frequency in Hertz. If specified, signals below this frequency will be filtered out. Default=None.

t_rfloat or None, optional

Repetition time, in seconds (sampling period). Set to None if not provided. Default=None.

dtype{dtype, “auto”}, optional

Data type toward which the data should be converted. If “auto”, the data will be converted to int32 if dtype is discrete and float32 if it is continuous.

resampling_target{“data”, “mask”, “maps”, None}, optional.

Gives which image gives the final shape/size:

• “data” means the atlas is resampled to the shape of the data if needed

• “mask” means the maps_img and images provided to fit() are resampled to the shape and affine of mask_img

• “maps” means the mask_img and images provided to fit() are resampled to the shape and affine of maps_img

• None means no resampling: if shapes and affines do not match, a ValueError is raised.

Default=”data”.

memoryinstance of joblib.Memory, str, or pathlib.Path

Used to cache the masking process. By default, no caching is done. If a str is given, it is the path to the caching directory.

memory_levelint, optional.

Rough estimator of the amount of memory used by caching. Higher value means more memory for caching. Zero means no caching. Default=0.

n_jobsint, optional.

The number of CPUs to use to do the computation. -1 means ‘all CPUs’. Default=1.

verboseint, optional

Verbosity level (0 means no message). Default=0.

reportsbool, optional

If set to True, data is saved in order to produce a report. Default=True.

See also

nilearn.maskers.NiftiMasker

nilearn.maskers.NiftiLabelsMasker

nilearn.maskers.NiftiMapsMasker

Notes

If resampling_target is set to “maps”, every 3D image processed by transform() will be resampled to the shape of maps_img. It may lead to a very large memory consumption if the voxel number in maps_img is large.

__init__(maps_img, mask_img=None, allow_overlap=True, smoothing_fwhm=None, standardize=False, standardize_confounds=True, high_variance_confounds=False, detrend=False, low_pass=None, high_pass=None, t_r=None, dtype=None, resampling_target='data', memory=Memory(location=None), memory_level=0, verbose=0, reports=True, n_jobs=1)

transform_imgs(imgs_list, confounds=None, n_jobs=1, sample_mask=None)

Extract signals from a list of 4D niimgs.

Parameters

%(imgs)s

Images to process. Each element of the list is a 4D image.

%(confounds)s

%(sample_mask)s

Returns

region_signalslist of 2D numpy.ndarray

List of signals for each map per subject. shape: list of (number of scans, number of maps)

transform(imgs, confounds=None, sample_mask=None)

Apply mask, spatial and temporal preprocessing

Parameters

%(imgs)s

Images to process. Each element of the list is a 4D image.

%(confounds)s

%(sample_mask)s

Returns

region_signalslist of 2D numpy.ndarray

List of signals for each map per subject. shape: list of (number of scans, number of maps)

fit(imgs=None, y=None)

Prepare signal extraction from regions.

All parameters are unused, they are for scikit-learn compatibility.

fit_transform(imgs, confounds=None, sample_mask=None)

Prepare and perform signal extraction.

generate_report(displayed_maps=10)

Generate an HTML report for the current NiftiMapsMasker object.

Note

This functionality requires to have Matplotlib installed.

Parameters

displayed_mapsint, or list, or ndarray, or “all”, optional

Indicates which maps will be displayed in the HTML report.

• If “all”: All maps will be displayed in the report.

masker.generate_report("all")

• If a list or ndarray: This indicates the indices of the maps to be displayed in the report. For example, the following code will generate a report with maps 6, 3, and 12, displayed in this specific order:

masker.generate_report([6, 3, 12])

• If an int: This will only display the first n maps, n being the value of the parameter. By default, the report will only contain the first 10 maps. Example to display the first 16 maps:

masker.generate_report(16)

Default=10.

Returns

reportnilearn.reporting.html_report.HTMLReport

HTML report for the masker.

get_params(deep=True)

Get parameters for this estimator.

Parameters

deepbool, default=True

If True, will return the parameters for this estimator and contained subobjects that are estimators.

Returns

paramsdict

Parameter names mapped to their values.

inverse_transform(region_signals)

Compute voxel signals from region signals

Any mask given at initialization is taken into account.

Parameters

region_signals1D/2D numpy.ndarray

Signal for each region. If a 1D array is provided, then the shape should be (number of elements,), and a 3D img will be returned. If a 2D array is provided, then the shape should be (number of scans, number of elements), and a 4D img will be returned.

Returns

voxel_signalsnibabel.Nifti1Image

Signal for each voxel. shape: that of maps.

set_output(*, transform=None)

Set output container.

See Introducing the set_output API for an example on how to use the API.

Parameters

transform{“default”, “pandas”}, default=None

Configure output of transform and fit_transform.

• “default”: Default output format of a transformer

• “pandas”: DataFrame output

• None: Transform configuration is unchanged

Returns

selfestimator instance

Estimator instance.

set_params(**params)

Set the parameters of this estimator.

The method works on simple estimators as well as on nested objects (such as Pipeline). The latter have parameters of the form <component>__<parameter> so that it’s possible to update each component of a nested object.

Parameters

**paramsdict

Estimator parameters.

Returns

selfestimator instance

Estimator instance.

transform_single_imgs(imgs, confounds=None, sample_mask=None)

Extract signals from a single 4D niimg.

Parameters

imgs3D/4D Niimg-like object

See Input and output: neuroimaging data representation. Images to process. If a 3D niimg is provided, a singleton dimension will be added to the output to represent the single scan in the niimg.

confoundsCSV file or array-like, optional

This parameter is passed to signal.clean. Please see the related documentation for details. shape: (number of scans, number of confounds)

sample_maskAny type compatible with numpy-array indexing, optional

shape: (number of scans - number of volumes removed, ) Masks the niimgs along time/fourth dimension to perform scrubbing (remove volumes with high motion) and/or non-steady-state volumes. This parameter is passed to signal.clean.

New in version 0.8.0.

Returns

region_signals2D numpy.ndarray

Signal for each map. shape: (number of scans, number of maps)

Warns

DeprecationWarning

If a 3D niimg input is provided, the current behavior (adding a singleton dimension to produce a 2D array) is deprecated. Starting in version 0.12, a 1D array will be returned for 3D inputs.

Examples using nilearn.maskers.MultiNiftiMapsMasker

Comparing connectomes on different reference atlases

Comparing connectomes on different reference atlases