예제 #1
0
def group_analysis(design, contrast):
    """ Compute group analysis effect, t, sd for `design` and `contrast`

    Saves to disk in 'group' analysis directory

    Parameters
    ----------
    design : {'block', 'event'}
    contrast : str
        contrast name
    """
    array = np.array  # shorthand
    # Directory where output will be written
    odir = futil.ensure_dir(futil.DATADIR, 'group', design, contrast)

    # Which subjects have this (contrast, design) pair?
    subj_con_dirs = futil.subj_des_con_dirs(design, contrast)
    if len(subj_con_dirs) == 0:
        raise ValueError('No subjects for %s, %s' % (design, contrast))

    # Assemble effects and sds into 4D arrays
    sds = []
    Ys = []
    for s in subj_con_dirs:
        sd_img = load_image(pjoin(s, "sd.nii"))
        effect_img = load_image(pjoin(s, "effect.nii"))
        sds.append(sd_img.get_data())
        Ys.append(effect_img.get_data())
    sd = array(sds)
    Y = array(Ys)

    # This function estimates the ratio of the fixed effects variance
    # (sum(1/sd**2, 0)) to the estimated random effects variance
    # (sum(1/(sd+rvar)**2, 0)) where rvar is the random effects variance.

    # The EM algorithm used is described in:
    #
    # Worsley, K.J., Liao, C., Aston, J., Petre, V., Duncan, G.H.,
    #    Morales, F., Evans, A.C. (2002). \'A general statistical
    #    analysis for fMRI data\'. NeuroImage, 15:1-15
    varest = onesample.estimate_varatio(Y, sd)
    random_var = varest['random']

    # XXX - if we have a smoother, use
    # random_var = varest['fixed'] * smooth(varest['ratio'])

    # Having estimated the random effects variance (and possibly smoothed it),
    # the corresponding estimate of the effect and its variance is computed and
    # saved.

    # This is the coordmap we will use
    coordmap = futil.load_image_ds105("fiac_00", "wanatomical.nii").coordmap

    adjusted_var = sd**2 + random_var
    adjusted_sd = np.sqrt(adjusted_var)

    results = onesample.estimate_mean(Y, adjusted_sd)
    for n in ['effect', 'sd', 't']:
        im = api.Image(results[n], copy(coordmap))
        save_image(im, pjoin(odir, "%s.nii" % n))
예제 #2
0
파일: ds105_example.py 프로젝트: Lx37/nipy
def group_analysis(design, contrast):
    """ Compute group analysis effect, t, sd for `design` and `contrast`

    Saves to disk in 'group' analysis directory

    Parameters
    ----------
    design : {'block', 'event'}
    contrast : str
        contrast name
    """
    array = np.array # shorthand
    # Directory where output will be written
    odir = futil.ensure_dir(futil.DATADIR, 'group', design, contrast)

    # Which subjects have this (contrast, design) pair?
    subj_con_dirs = futil.subj_des_con_dirs(design, contrast)
    if len(subj_con_dirs) == 0:
        raise ValueError('No subjects for %s, %s' % (design, contrast))

    # Assemble effects and sds into 4D arrays
    sds = []
    Ys = []
    for s in subj_con_dirs:
        sd_img = load_image(pjoin(s, "sd.nii"))
        effect_img = load_image(pjoin(s, "effect.nii"))
        sds.append(sd_img.get_data())
        Ys.append(effect_img.get_data())
    sd = array(sds)
    Y = array(Ys)

    # This function estimates the ratio of the fixed effects variance
    # (sum(1/sd**2, 0)) to the estimated random effects variance
    # (sum(1/(sd+rvar)**2, 0)) where rvar is the random effects variance.

    # The EM algorithm used is described in:
    #
    # Worsley, K.J., Liao, C., Aston, J., Petre, V., Duncan, G.H.,
    #    Morales, F., Evans, A.C. (2002). \'A general statistical
    #    analysis for fMRI data\'. NeuroImage, 15:1-15
    varest = onesample.estimate_varatio(Y, sd)
    random_var = varest['random']

    # XXX - if we have a smoother, use
    # random_var = varest['fixed'] * smooth(varest['ratio'])

    # Having estimated the random effects variance (and possibly smoothed it),
    # the corresponding estimate of the effect and its variance is computed and
    # saved.

    # This is the coordmap we will use
    coordmap = futil.load_image_ds105("fiac_00","wanatomical.nii").coordmap

    adjusted_var = sd**2 + random_var
    adjusted_sd = np.sqrt(adjusted_var)

    results = onesample.estimate_mean(Y, adjusted_sd) 
    for n in ['effect', 'sd', 't']:
        im = api.Image(results[n], copy(coordmap))
        save_image(im, pjoin(odir, "%s.nii" % n))
예제 #3
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def view_thresholdedT(design, contrast, threshold, inequality=np.greater):
    """
    A mayavi isosurface view of thresholded t-statistics

    Parameters
    ----------
    design : {'standard'}
    contrast : str
    threshold : float
    inequality : {np.greater, np.less}, optional
    """
    maska = np.asarray(MASK)
    tmap = np.array(load_image_ds105('group', design, contrast, 't.nii'))
    test = inequality(tmap, threshold)
    tval = np.zeros(tmap.shape)
    tval[test] = tmap[test]

    # XXX make the array axes agree with mayavi2
    avganata = np.array(AVGANAT)
    avganat_iso = mlab.contour3d(avganata * maska, opacity=0.3, contours=[3600],
                               color=(0.8,0.8,0.8))

    avganat_iso.actor.property.backface_culling = True
    avganat_iso.actor.property.ambient = 0.3

    tval_iso = mlab.contour3d(tval * MASK, color=(0.8,0.3,0.3),
                            contours=[threshold])
    return avganat_iso, tval_iso
예제 #4
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def fixed_effects(subj, design):
    """ Fixed effects (within subject) for OpenfMRI ds105 model

    Finds run by run estimated model results, creates fixed effects results
    image per subject.

    Parameters
    ----------
    subj : int
        subject number 1..6 inclusive
    design : {'standard'}
        design type
    """
    # First, find all the effect and standard deviation images
    # for the subject and this design type
    path_dict = futil.path_info_design(subj, design)
    rootdir = path_dict['rootdir']
    # The output directory
    fixdir = pjoin(rootdir, "fixed")
    # Fetch results images from run estimations
    results = futil.results_table(path_dict)
    # Get our hands on the relevant coordmap to save our results
    coordmap = futil.load_image_ds105("_%02d" % subj,
                                      "wanatomical.nii").coordmap
    # Compute the "fixed" effects for each type of contrast
    for con in results:
        fixed_effect = 0
        fixed_var = 0
        for effect, sd in results[con]:
            effect = load_image(effect).get_data()
            sd = load_image(sd).get_data()
            var = sd**2

            # The optimal, in terms of minimum variance, combination of the
            # effects has weights 1 / var
            #
            # XXX regions with 0 variance are set to 0
            # XXX do we want this or np.nan?
            ivar = np.nan_to_num(1. / var)
            fixed_effect += effect * ivar
            fixed_var += ivar

        # Now, compute the fixed effects variance and t statistic
        fixed_sd = np.sqrt(fixed_var)
        isd = np.nan_to_num(1. / fixed_sd)
        fixed_t = fixed_effect * isd

        # Save the results
        odir = futil.ensure_dir(fixdir, con)
        for a, n in zip([fixed_effect, fixed_sd, fixed_t],
                        ['effect', 'sd', 't']):
            im = api.Image(a, copy(coordmap))
            save_image(im, pjoin(odir, '%s.nii' % n))
예제 #5
0
파일: ds105_example.py 프로젝트: Lx37/nipy
def fixed_effects(subj, design):
    """ Fixed effects (within subject) for OpenfMRI ds105 model

    Finds run by run estimated model results, creates fixed effects results
    image per subject.

    Parameters
    ----------
    subj : int
        subject number 1..6 inclusive
    design : {'standard'}
        design type
    """
    # First, find all the effect and standard deviation images
    # for the subject and this design type
    path_dict = futil.path_info_design(subj, design)
    rootdir = path_dict['rootdir']
    # The output directory
    fixdir = pjoin(rootdir, "fixed")
    # Fetch results images from run estimations
    results = futil.results_table(path_dict)
    # Get our hands on the relevant coordmap to save our results
    coordmap = futil.load_image_ds105("_%02d" % subj,
                                     "wanatomical.nii").coordmap
    # Compute the "fixed" effects for each type of contrast
    for con in results:
        fixed_effect = 0
        fixed_var = 0
        for effect, sd in results[con]:
            effect = load_image(effect).get_data()
            sd = load_image(sd).get_data()
            var = sd ** 2

            # The optimal, in terms of minimum variance, combination of the
            # effects has weights 1 / var
            #
            # XXX regions with 0 variance are set to 0
            # XXX do we want this or np.nan?
            ivar = np.nan_to_num(1. / var)
            fixed_effect += effect * ivar
            fixed_var += ivar

        # Now, compute the fixed effects variance and t statistic
        fixed_sd = np.sqrt(fixed_var)
        isd = np.nan_to_num(1. / fixed_sd)
        fixed_t = fixed_effect * isd

        # Save the results
        odir = futil.ensure_dir(fixdir, con)
        for a, n in zip([fixed_effect, fixed_sd, fixed_t],
                        ['effect', 'sd', 't']):
            im = api.Image(a, copy(coordmap))
            save_image(im, pjoin(odir, '%s.nii' % n))
예제 #6
0
#-----------------------------------------------------------------------------
# Globals
#-----------------------------------------------------------------------------

SUBJECTS = tuple(range(1,7))
RUNS = tuple(range(1, 13))
DESIGNS = ('standard',)
CONTRASTS = ('speaker_0', 'speaker_1',
             'sentence_0', 'sentence_1',
             'sentence:speaker_0',
             'sentence:speaker_1')

# XXX: this mask was copied by hand from one of the subjects
# we should have a function to create this mask from the ds105 data
GROUP_MASK = futil.load_image_ds105('group', 'mask.nii.gz') 
TINY_MASK = np.zeros(GROUP_MASK.shape, np.bool)
TINY_MASK[30:32,40:42,30:32] = 1

#-----------------------------------------------------------------------------
# Public functions
#-----------------------------------------------------------------------------

# For group analysis

def run_model(subj, run):
    """
    Single subject fitting of FIAC model
    """
    #----------------------------------------------------------------------
    # Set initial parameters of the FIAC dataset
예제 #7
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import ds105_util as futil
reload(futil)  # while developing interactively

#-----------------------------------------------------------------------------
# Globals
#-----------------------------------------------------------------------------

SUBJECTS = tuple(range(1, 7))
RUNS = tuple(range(1, 13))
DESIGNS = ('standard', )
CONTRASTS = ('speaker_0', 'speaker_1', 'sentence_0', 'sentence_1',
             'sentence:speaker_0', 'sentence:speaker_1')

# XXX: this mask was copied by hand from one of the subjects
# we should have a function to create this mask from the ds105 data
GROUP_MASK = futil.load_image_ds105('group', 'mask.nii.gz')
TINY_MASK = np.zeros(GROUP_MASK.shape, np.bool)
TINY_MASK[30:32, 40:42, 30:32] = 1

#-----------------------------------------------------------------------------
# Public functions
#-----------------------------------------------------------------------------

# For group analysis


def run_model(subj, run):
    """
    Single subject fitting of OpenfMRI ds105 model
    """
    #----------------------------------------------------------------------