MRI Laboratory

Pisa, Italy

MRI Laboratory

Pisa, Italy
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Bonino D.,University of Pisa | Ricciardi E.,University of Pisa | Ricciardi E.,MRI Laboratory | Bernardi G.,University of Pisa | And 5 more authors.
Neuropsychologia | Year: 2015

Although vision offers distinctive information to space representation, individuals who lack vision since birth often show perceptual and representational skills comparable to those found in sighted individuals. However, congenitally blind individuals may result in impaired spatial analysis, when engaging in 'visual' spatial features (e.g., perspective or angle representation) or complex spatial mental abilities. In the present study, we measured behavioral and brain responses using functional magnetic resonance imaging in sighted and congenitally blind individuals during spatial imagery based on a modified version of the mental clock task (e.g., angle discrimination) and a simple recognition control condition, as conveyed across distinct sensory modalities: visual (sighted individuals only), tactile and auditory. Blind individuals were significantly less accurate during the auditory task, but comparable-to-sighted during the tactile task. As expected, both groups showed common neural activations in intraparietal and superior parietal regions across visual and non-visual spatial perception and imagery conditions, indicating the more abstract, sensory independent functional organization of these cortical areas, a property that we named supramodality. At the same time, however, comparisons in brain responses and functional connectivity patterns across experimental conditions demonstrated also a functional lateralization, in a way that correlated with the distinct behavioral performance in blind and sighted individuals. Specifically, blind individuals relied more on right parietal regions, mainly in the tactile and less in the auditory spatial processing. In sighted, spatial representation across modalities relied more on left parietal regions. In conclusions, intraparietal and superior parietal regions subserve supramodal spatial representations in sighted and congenitally blind individuals. Differences in their recruitment across non-visual spatial processing in sighted and blind individuals may be related to distinctive behavioral performance and/or mental strategies adopted when they deal with the same spatial representation as conveyed through different sensory modalities. © 2015 Elsevier Ltd.

Forzoni L.,Esaote S.p.A. | D'Onofrio S.,Esaote S.p.A. | Beni S.D.,Esaote S.p.A. | Lagana M.M.,MRI Laboratory | And 4 more authors.
Biomedizinische Technik | Year: 2012

Three-dimensional (3D) Panoramic ultrasound imaging is a Virtual Navigator option which allows the acquisition of ultrasound (US) volumes of Doppler signals, then it merges them together to obtain a panoramic volume dataset of the full scanned area. This technology can also be used for the fusion imaging between a 3D Panoramic US dataset and a second imaging modality as Magnetic Resonance Imaging (MRI) or Computed Tomography (CT). In the present work Virtual Navigator 3D Panoramic technology was applied to the transcranial district, where hemodynamic data provided by 3D US scans of Power Doppler signals were fused with the anatomical brain MRI data. A Motion Control Sensor enabled correction of the examined subject's movements, even after the Virtual Navigator registration procedure. In vitro tests for the Motion Compensation technology precision measurement and in vivo tests for the feasibility of the fusion of 3D Panoramic US Power Doppler data with anatomical MRI are provided as well. © 2012 by Walter de Gruyter Berlin Boston.

Ricciardi E.,University of Pisa | Ricciardi E.,MRI Laboratory | Handjaras G.,University of Pisa | Bonino D.,University of Pisa | And 5 more authors.
PLoS ONE | Year: 2013

The representation of actions within the action-observation network is thought to rely on a distributed functional organization. Furthermore, recent findings indicate that the action-observation network encodes not merely the observed motor act, but rather a representation that is independent from a specific sensory modality or sensory experience. In the present study, we wished to determine to what extent this distributed and 'more abstract' representation of action is truly supramodal, i.e. shares a common coding across sensory modalities. To this aim, a pattern recognition approach was employed to analyze neural responses in sighted and congenitally blind subjects during visual and/or auditory presentation of hand-made actions. Multivoxel pattern analyses-based classifiers discriminated action from non-action stimuli across sensory conditions (visual and auditory) and experimental groups (blind and sighted). Moreover, these classifiers labeled as 'action' the pattern of neural responses evoked during actual motor execution. Interestingly, discriminative information for the action/non action classification was located in a bilateral, but left-prevalent, network that strongly overlaps with brain regions known to form the action-observation network and the human mirror system. The ability to identify action features with a multivoxel pattern analyses-based classifier in both sighted and blind individuals and independently from the sensory modality conveying the stimuli clearly supports the hypothesis of a supramodal, distributed functional representation of actions, mainly within the action-observation network. © 2013 Ricciardi et al.

Baselli G.,Polytechnic of Milan | Bergsland N.,Polytechnic of Milan | Bergsland N.,MRI Laboratory | Costantini I.,Polytechnic of Milan | And 9 more authors.
2015 AEIT International Annual Conference, AEIT 2015 | Year: 2015

Resting state (RS) functional magnetic resonance images (rsfMRI) were analyzed by spatial independent component analysis (sICA). Functional connectivity (FC) was further analyzed within the identified RS networks either by high dimension sICA or by local clustering. The latter approach permitted to drive a matched structural connectivity (SC) based on probabilistic tractography between the same clusters. Cortex segmentation tools ad diffusion MRI were used to correlate fiber and cortical damage. Methods and results are here compared concerning the translational fall-outs and the applicability in the evaluation and follow-up of neurodegenerative diseases. Emphasis is given to the integration of image, signal, and data processing methods. © 2015 AEIT.

Tomaiuolo F.,Volterra | Campana S.,University of Padua | Collins D.L.,Montreal Neurological Institute | Fonov V.S.,Montreal Neurological Institute | And 8 more authors.
PLoS ONE | Year: 2014

We examined the effects of visual deprivation at birth on the development of the corpus callosum in a large group of congenitally blind individuals. We acquired high-resolution T1-weighted MRI scans in 28 congenitally blind and 28 normal sighted subjects matched for age and gender. There was no overall group effect of visual deprivation on the total surface area of the corpus callosum. However, subdividing the corpus callosum into five subdivisions revealed significant regional changes in its three most posterior parts. Compared to the sighted controls, congenitally blind individuals showed a 12% reduction in the splenium, and a 20% increase in the isthmus and the posterior part of the body. A shape analysis further revealed that the bending angle of the corpus callosum was more convex in congenitally blind compared to the sighted control subjects. The observed morphometric changes in the corpus callosum are in line with the well-described cross-modal functional and structural neuroplastic changes in congenital blindness. © 2014 Tomaiuolo et al.

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