G L Romani

Publications of G L Romani

• Reorganization of Functional Connectivity of the Language Network in Patients with Brain Gliomas.

  Authors: C Briganti, C Sestieri, P A Mattei, R Esposito, R J Galzio, A Tartaro, G L Romani, M Caulo

  AJNR. American journal of neuroradiology. 05/2012;

  BACKGROUND AND PURPOSE:fcMRI measures spontaneous and synchronous fluctuations of BOLD signal between spatially remote brain regions. The present study investigated potential LN fcMRI modificationsBACKGROUND AND PURPOSE:fcMRI measures spontaneous and synchronous fluctuations of BOLD signal between spatially remote brain regions. The present study investigated potential LN fcMRI modifications induced by left hemisphere brain gliomas.MATERIALS AND METHODS:We retrospectively evaluated fcMRI in 39 right-handed patients with a left hemisphere brain glioma and 13 healthy controls. Patients and controls performed a verb-generation task to identify individual BOLD activity in the left IFG (Broca area); the active region was used as seed to create whole-brain background connectivity maps and to identify the LN (including bilateral regions of the IFG, STS, and TPJ) following regression of task-evoked activity. We assessed differences between patients and controls in the pattern of functional connectivity of the LN, as well as potential effects of tumor position, histopathology, and volume.RESULTS:Global fcMRI of the LN was significantly reduced in patients with tumor compared with controls. Specifically, fcMRI was significantly reduced within seed regions of the affected hemisphere (left intrahemispheric fcMRI) and between the TPJ of the 2 hemispheres. In patients, the left TPJ node showed the greatest decrease of functional connectivity within the LN.CONCLUSIONS:The presence of a brain tumor in the left hemisphere significantly reduced the degree of fcMRI between language-related brain regions. The pattern of fcMRI was influenced by tumor position but was not restricted to the area immediately surrounding the tumor because the connectivity between remote and contralateral areas was also affected.

• Diffusion tensor imaging of subependymal heterotopia.

  Authors: C Briganti, R Navarra, C Celentano, B Matarrelli, A Tartaro, G L Romani, M Caulo

  Epilepsy research. 09/2011; 98(2-3):251-4.

  A magnetic resonance (MR) diffusion tensor imaging (DTI) study was performed in a newborn with bilateral subependymal heterotopia (SE). White matter fractional anisotropy (FA), axial diffusivity (AD)A magnetic resonance (MR) diffusion tensor imaging (DTI) study was performed in a newborn with bilateral subependymal heterotopia (SE). White matter fractional anisotropy (FA), axial diffusivity (AD) and radial diffusivity (RD) were compared to values obtained in four newborns with moderate perinatal asphyxia and normal MRI findings. The reduction of FA and increase of AD and RD in the newborn with SE were the in vivo late expression of alterations in the intermediate zone, with an underlying arrest of neuronal migration.

• Comparison of hypothesis- and a novel hybrid data/hypothesis-driven method of functional MR imaging analysis in patients with brain gliomas.

  Authors: M Caulo, R Esposito, D Mantini, C Briganti, C Sestieri, P A Mattei, C Colosimo, G L Romani, A Tartaro

  AJNR. American journal of neuroradiology. 03/2011; 32(6):1056-64.

  An alternative technique, which is less influenced by tumor- and patient-related factors, is required to overcome the limits of GLM analysis of fMRI data in patients. The aim of this study was toAn alternative technique, which is less influenced by tumor- and patient-related factors, is required to overcome the limits of GLM analysis of fMRI data in patients. The aim of this study was to statistically assess differences in the identification of language regions and hemispheric lateralization of language function between controls and patients as estimated by both the GLM and a novel combined ICA-GLM procedure. We retrospectively evaluated 42 patients with pathologically confirmed brain gliomas of the left frontal and/or temporoparietal lobes and a control group of 14 age-matched healthy volunteers who underwent BOLD fMRI to lateralize language functions in the cerebral hemispheres. Data were processed by using a classic GLM and ICA-GLM. ICA-GLM demonstrated a higher sensitivity in detecting language activation, specifically in the left TPJ of patients. There were no significant differences between the GLM and ICA-GLM in controls; however, statistically significant differences were observed by using ICA-GLM for the LI in patients. For the computation of the LI, ICA-GLM was less influenced by the chosen statistical threshold compared with the GLM. We suggest the use of the ICA-GLM as a valid alternative to the classic GLM method for presurgical mapping in patients with brain tumors and to replicate the present results in a broader sample of patients.

• Functional connectivity MR imaging of the language network in patients with drug-resistant epilepsy.

  Authors: E Pravatà, C Sestieri, D Mantini, C Briganti, G Colicchio, C Marra, C Colosimo, A Tartaro, G L Romani, M Caulo

  AJNR. American journal of neuroradiology. 12/2010; 32(3):532-40.

  Subtle linguistic dysfunction and reorganization of the language network were described in patients with epilepsy, suggesting the occurrence of plasticity changes. We used resting state FC-MRI toSubtle linguistic dysfunction and reorganization of the language network were described in patients with epilepsy, suggesting the occurrence of plasticity changes. We used resting state FC-MRI to investigate the effects induced by chronic epilepsy on the connectivity of the language-related brain regions and correlated it with language performance. FC-MRI was evaluated in 22 right-handed patients with drug-resistant epilepsy (11 with LE and 11 with RE) and in 12 healthy volunteers. Neuropsychological assessment of verbal IQ was performed. Patients and controls underwent BOLD fMRI with a verb-generation task, and language function was lateralized by an LI. Intrinsic activity fluctuations for FC analysis were extracted from data collected during the task. Six seeding cortical regions for speech in both hemispheres were selected to obtain a measure of the connectivity pattern among the language networks. Patients with LE presented atypical language lateralization and an overall reduced connectivity of the language network with respect to controls. In patients with both LE and RE, the mean FC was significantly reduced within the left (dominant) hemisphere and between the 2 hemispheres. In patients with LE, there was a positive correlation between verbal IQ scores and the left intrahemispheric FC. In patients with intractable epilepsy, FC-MRI revealed an overall reduction and reorganization of the connectivity pattern within the language network. FC was reduced in the left hemisphere regardless of the epileptogenic focus side and was positively correlated with linguistic performance only in patients with LE.

• Multimodal integration of fMRI and EEG data for high spatial and temporal resolution analysis of brain networks.

  Authors: D Mantini, L Marzetti, M Corbetta, G L Romani, C Del Gratta

  Brain topography. 06/2010; 23(2):150-8.

  Two major non-invasive brain mapping techniques, electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), have complementary advantages with regard to their spatial and temporalTwo major non-invasive brain mapping techniques, electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), have complementary advantages with regard to their spatial and temporal resolution. We propose an approach based on the integration of EEG and fMRI, enabling the EEG temporal dynamics of information processing to be characterized within spatially well-defined fMRI large-scale networks. First, the fMRI data are decomposed into networks by means of spatial independent component analysis (sICA), and those associated with intrinsic activity and/or responding to task performance are selected using information from the related time-courses. Next, the EEG data over all sensors are averaged with respect to event timing, thus calculating event-related potentials (ERPs). The ERPs are subjected to temporal ICA (tICA), and the resulting components are localized with the weighted minimum norm (WMNLS) algorithm using the task-related fMRI networks as priors. Finally, the temporal contribution of each ERP component in the areas belonging to the fMRI large-scale networks is estimated. The proposed approach has been evaluated on visual target detection data. Our results confirm that two different components, commonly observed in EEG when presenting novel and salient stimuli, respectively, are related to the neuronal activation in large-scale networks, operating at different latencies and associated with different functional processes.

• Elevated response of human amygdala to neutral stimuli in mild post traumatic stress disorder: neural correlates of generalized emotional response.

  Authors: M Brunetti, G Sepede, G Mingoia, C Catani, A Ferretti, A Merla, C Del Gratta, G L Romani, C Babiloni

  Neuroscience. 04/2010; 168(3):670-9.

  Previous evidence from functional magnetic resonance imaging (fMRI) studies has shown that amygdala responses to emotionally neutral pictures are exaggerated at a group level in patients with severePrevious evidence from functional magnetic resonance imaging (fMRI) studies has shown that amygdala responses to emotionally neutral pictures are exaggerated at a group level in patients with severe post-traumatic stress disorder (PTSD) [Hendler T, Rotshtein P, Yeshurun Y, Weizmann T, Kahn I, Ben-Bashat D, Malach R, Bleich A (2003) Neuroimage 19(3):587-600]. The present fMRI study tested the hypothesis that amygdala responses are elevated not only in response to negative pictures but also to neutral pictures as a function of disease severity in patients with mild symptoms and in subjects who did not develop symptoms. To this end, fMRI scans were performed in 10 patients with mild PTSD and 10 healthy controls (both victims of a bank robbery), during the execution of a visuo-attentional task in which they were asked to observe emotionally negative or neutral pictures. Control subjects showed enhanced amygdala responses to emotionally negative stimuli compared to neutral stimuli. On the contrary, PTSD patients were characterized by high amygdala responses to both neutral and emotional pictures, with no statistically significant difference between the two classes of stimuli. In the entire group, we found correlations among the severity of the PTSD symptoms, task performance, and amygdala activation during the processing of neutral stimuli. Results of this study suggest that amygdala responses and the selectivity of the emotional response to neutral stimuli are elevated as a function of disease severity in PTSD patients with mild symptoms.

• Persistent genital arousal disorder associated with functional hyperconnectivity of an epileptic focus.

  Authors: F Anzellotti, R Franciotti, L Bonanni, G Tamburro, M G Perrucci, A Thomas, V Pizzella, G L Romani, M Onofrj

  Neuroscience. 02/2010; 167(1):88-96.

  Persistent Genital Arousal Disorder (PGAD) refers to the experience of persistent sensations of genital arousal that are felt to be unprovoked, intrusive and unrelieved by one or several orgasms. ItPersistent Genital Arousal Disorder (PGAD) refers to the experience of persistent sensations of genital arousal that are felt to be unprovoked, intrusive and unrelieved by one or several orgasms. It is often mistaken for hypersexuality since PGAD often results in a high frequency of sexual behaviour. At present little is known with certainty about the etiology of this condition. We described a woman with typical PGAD symptoms and orgasmic seizures that we found to be related to a specific epileptic focus. We performed a EEG/MEG and fMRI spontaneous activity study during genital arousal symptoms and after the chronic administration of 300 mg/day of topiramate. From MEG data an epileptic focus was localized in the left posterior insular gyrus (LPIG). FMRI data evidenced that sexual excitation symptoms with PGAD could be correlated with an increased functional connectivity (FC) between different brain areas: LPIG (epileptic focus), left middle frontal gyrus, left inferior and superior temporal gyrus and left inferior parietal lobe. The reduction of the FC observed after antiepileptic therapy was more marked in the left than in the right hemisphere in agreement with the lateralization identified by MEG results. Treatment completely abolished PGAD symptoms and functional hyperconnectivity. The functional hyperconnectivity found in the neuronal network including the epileptic focus could suggest a possible central mechanism for PGAD.

• An fMRI investigation on image generation in different sensory modalities: The influence of vividness.

  Authors: M Olivetti Belardinelli, M Palmiero, C Sestieri, D Nardo, R Di Matteo, A Londei, A D'Ausilio, A Ferretti, C Del Gratta, G L Romani

  Acta psychologica. 09/2009;

  In the present fMRI study the issue of the specific cortices activation during imagery generation in different sensory modalities is addressed. In particular, we tested whether the vividnessIn the present fMRI study the issue of the specific cortices activation during imagery generation in different sensory modalities is addressed. In particular, we tested whether the vividness variability of imagery was reflected in the BOLD signal within specific sensory cortices. Subjects were asked to generate a mental image for each auditory presented sentence. Each imagery modality was contrasted with an abstract sentence condition. In addition, subjects were asked to fill the Italian version of the Questionnaire Upon Mental Imagery (QMI) prior to each neuroimaging session. In general, greater involvement of sensory specific cortices in high-vivid versus low-vivid subjects was found for visual (occipital), gustatory (anterior insula), kinaesthetic (pre-motor), and tactile and for somatic (post-central parietal) imagery modalities. These results support the hypothesis that vividness is related to image format: high-vivid subjects would create more analogical representations relying on the same specific neural substrates active during perception with respect to low-vivid subjects. Results are also discussed according to the simulation perspective.

• Motor control in young patients with unilateral brain lesions: an MEG study.

  Authors: P Belardinelli, L Ciancetta, M Staudt, V Pizzella, A Londei, N Birbaumer, G L Romani, C Braun

  Cognitive processing. 09/2009; 10 Suppl 2:S185-8.

• Empirical Markov Chain Monte Carlo Bayesian analysis of fMRI data.

  Authors: F de Pasquale, C Del Gratta, G L Romani

  NeuroImage. 09/2008; 42(1):99-111.

  In this work an Empirical Markov Chain Monte Carlo Bayesian approach to analyse fMRI data is proposed. The Bayesian framework is appealing since complex models can be adopted in the analysis both forIn this work an Empirical Markov Chain Monte Carlo Bayesian approach to analyse fMRI data is proposed. The Bayesian framework is appealing since complex models can be adopted in the analysis both for the image and noise model. Here, the noise autocorrelation is taken into account by adopting an AutoRegressive model of order one and a versatile non-linear model is assumed for the task-related activation. Model parameters include the noise variance and autocorrelation, activation amplitudes and the hemodynamic response function parameters. These are estimated at each voxel from samples of the Posterior Distribution. Prior information is included by means of a 4D spatio-temporal model for the interaction between neighbouring voxels in space and time. The results show that this model can provide smooth estimates from low SNR data while important spatial structures in the data can be preserved. A simulation study is presented in which the accuracy and bias of the estimates are addressed. Furthermore, some results on convergence diagnostic of the adopted algorithm are presented. To validate the proposed approach a comparison of the results with those from a standard GLM analysis, spatial filtering techniques and a Variational Bayes approach is provided. This comparison shows that our approach outperforms the classical analysis and is consistent with other Bayesian techniques. This is investigated further by means of the Bayes Factors and the analysis of the residuals. The proposed approach applied to Blocked Design and Event Related datasets produced reliable maps of activation.

• Trigeminal activation using chemical, electrical, and mechanical stimuli.

  Authors: E Iannilli, C Del Gratta, J C Gerber, G L Romani, T Hummel

  Pain. 07/2008;

  Tactile, proprioceptive, and nociceptive information, including also chemosensory functions are expressed in the trigeminal nerve sensory response. To study differences in the processing of differentTactile, proprioceptive, and nociceptive information, including also chemosensory functions are expressed in the trigeminal nerve sensory response. To study differences in the processing of different stimulus qualities, we performed a study based on functional magnetic resonance imaging. The first trigeminal branch (ophthalmic nerve) was activated by (a) intranasal chemical stimulation with gaseous CO(2) which produces stinging and burning sensations, but is virtually odorless, (b) painful, but not nociceptive specific cutaneous electrical stimulation, and (c) cutaneous mechanical stimulation using air puffs. Eighteen healthy subjects participated (eight men, 10 women, mean age 31 years). Painful stimuli produced patterns of activation similar to what has been reported for other noxious stimuli, namely activation in the primary and secondary somatosensory cortices, anterior cingulate cortex, insular cortex, and thalamus. In addition, analyses indicated intensity-related activation in the prefrontal cortex which was specifically involved in the evaluation of stimulus intensity. Importantly, the results also indicated similarities between activation patterns after intranasal chemosensory trigeminal stimulation and patterns usually found following intranasal odorous stimulation, indicating the intimate connection between these two systems in the processing of sensory information.

• Hypothalamus, sexual arousal and psychosexual identity in human males: a functional magnetic resonance imaging study.

  Authors: M Brunetti, C Babiloni, A Ferretti, C Del Gratta, A Merla, M Olivetti Belardinelli, G L Romani

  The European journal of neuroscience. 07/2008; 27(11):2922-7.

  In a recent functional magnetic resonance imaging study, a complex neural circuit was shown to be involved in human males during sexual arousal [A. Ferretti et al. (2005) Neuroimage, 26, 1086]. AtIn a recent functional magnetic resonance imaging study, a complex neural circuit was shown to be involved in human males during sexual arousal [A. Ferretti et al. (2005) Neuroimage, 26, 1086]. At group level, there was a specific correlation between penile erection and activations in anterior cingulate, insula, amygdala, hypothalamus and secondary somatosensory regions. However, it is well known that there are remarkable inter-individual differences in the psychological view and attitude to sex of human males. Therefore, a crucial issue is the relationship among cerebral responses, sexual arousal and psychosexual identity at individual level. To address this issue, 18 healthy male subjects were recruited. Their deep sexual identity (DSI) was assessed following the construct revalidation by M. Olivetti Belardinelli [(1994) Sci. Contrib. Gen. Psychol., 11, 131] of the Franck drawing completion test, a projective test providing, according to this revalidation, quantitative scores on 'accordance/non-accordance' between self-reported and psychological sexual identity. Cerebral activity was evaluated by means of functional magnetic resonance imaging during hard-core erotic movies and sport movies. Results showed a statistically significant positive correlation between the blood oxygen level-dependent signal in bilateral hypothalamus and the Franck drawing completion test score during erotic movies. The higher the blood oxygen level-dependent activation in bilateral hypothalamus, the higher the male DSI profile. These results suggest that, in male subjects, inter-individual differences in the DSI are strongly correlated with blood flow to the bilateral hypothalamus, a dimorphic brain region deeply implicated in instinctual drives including reproduction.

• A frontoparietal network for spatial attention reorienting in the auditory domain: a human fMRI/MEG study of functional and temporal dynamics.

  Authors: M Brunetti, S Della Penna, A Ferretti, C Del Gratta, F. Cianflone, P Belardinelli, M Caulo, V Pizzella, M Olivetti Belardinelli, G L Romani

  Cerebral cortex (New York, N.Y. : 1991). 06/2008; 18(5):1139-47.

  Several studies have identified a supramodal network critical to the reorienting of attention toward stimuli at novel locations and which involves the right temporoparietal junction and the inferiorSeveral studies have identified a supramodal network critical to the reorienting of attention toward stimuli at novel locations and which involves the right temporoparietal junction and the inferior frontal areas. The present functional magnetic resonance imaging (fMRI)\magnetoencephalography (MEG) study investigates: 1) the cerebral circuit underlying attentional reorienting to spatially varying sound locations; 2) the circuit related to the regular change of sound location in the same hemifield, the change of sound location across hemifields, or sounds presented randomly at different locations on the azimuth plane; 3) functional temporal dynamics of the observed cortical areas exploiting the complementary characteristics of the fMRI and MEG paradigms. fMRI results suggest 3 distinct roles: the supratemporal plane appears modulated by variations of sound location; the inferior parietal lobule is modulated by the cross-meridian effect; and the inferior frontal cortex is engaged by the inhibition of a motor response. MEG data help to elucidate the temporal dynamics of this network by providing high-resolution time series with which to measure latency of neural activation manipulated by the reorienting of attention.

• Improving MEG source localizations: an automated method for complete artifact removal based on independent component analysis.

  Authors: D Mantini, R Franciotti, G L Romani, V Pizzella

  NeuroImage. 04/2008; 40(1):160-73.

  The major limitation for the acquisition of high-quality magnetoencephalography (MEG) recordings is the presence of disturbances of physiological and technical origins: eye movements, cardiacThe major limitation for the acquisition of high-quality magnetoencephalography (MEG) recordings is the presence of disturbances of physiological and technical origins: eye movements, cardiac signals, muscular contractions, and environmental noise are serious problems for MEG signal analysis. In the last years, multi-channel MEG systems have undergone rapid technological developments in terms of noise reduction, and many processing methods have been proposed for artifact rejection. Independent component analysis (ICA) has already shown to be an effective and generally applicable technique for concurrently removing artifacts and noise from the MEG recordings. However, no standardized automated system based on ICA has become available so far, because of the intrinsic difficulty in the reliable categorization of the source signals obtained with this technique. In this work, approximate entropy (ApEn), a measure of data regularity, is successfully used for the classification of the signals produced by ICA, allowing for an automated artifact rejection. The proposed method has been tested using MEG data sets collected during somatosensory, auditory and visual stimulation. It was demonstrated to be effective in attenuating both biological artifacts and environmental noise, in order to reconstruct clear signals that can be used for improving brain source localizations.

• Power map during painful and nonpainful stimulation using beamformer technique

  Authors: R Franciotti, L Ciancetta, S Della Penna, P Belardinelli, V Pizzella, G L Romani

  Noninvasive Functional Source Imaging of the Brain and Heart and the International Conference on Functional Biomedical Imaging, 2007. NFSI-ICFBI 2007. Joint Meeting of the 6th International Symposium on; 11/2007

  Pain can influence brain processing on many levels, not only in terms of proper pain processing but also in terms of consciousness such as attention, information selection, anticipation . FunctionalPain can influence brain processing on many levels, not only in terms of proper pain processing but also in terms of consciousness such as attention, information selection, anticipation . Functional neuroimaging attempts to distinguish brain responses related to the expectation of pain from those associated with the experience of pain. The aim of the present study is to investigate brain regions involved in the emotional aspect of pain perception using beamforming technique in the alpha range.

• Neural Correlates of Mindfulness and Concentration in Buddhist Monks: A fMRI study

  Authors: A. Raffone, A. Manna, G.M. Perrucci, A. Ferretti, C. Del Gratta, M.O. Belardinelli, G.L. Romani

  Noninvasive Functional Source Imaging of the Brain and Heart and the International Conference on Functional Biomedical Imaging, 2007. NFSI-ICFBI 2007. Joint Meeting of the 6th International Symposium on; 11/2007

  Recent neuroimaging studies have shown consistent neural correlates of meditation states and traits. These studies present important implications for understanding core brain systems, also forRecent neuroimaging studies have shown consistent neural correlates of meditation states and traits. These studies present important implications for understanding core brain systems, also for clinical applications. In our fMRI study, we investigate neural correlates of both concentrative and mindfulness-based meditation forms, in long-term meditators (Buddhist monks). We found selective activation and deactivation patterns associated to these meditation forms, including the involvement of left frontoparietal areas in mindfulness-based meditation. Our findings present important implications for current models of awareness.

• MEG-EEG-fMRI: What can be gained in the Study of the Brain with a Multimodal Approach

  Authors: C. Del Gratta, M. Brunetti, D. Mantini, G.L. Romani

  Noninvasive Functional Source Imaging of the Brain and Heart and the International Conference on Functional Biomedical Imaging, 2007. NFSI-ICFBI 2007. Joint Meeting of the 6th International Symposium on; 11/2007

  In this short review we describe the potentialities, the difficulties, and the most common methods of combining EEG/MEG and fMRI data into a single neuroimaging technique with high spatial andIn this short review we describe the potentialities, the difficulties, and the most common methods of combining EEG/MEG and fMRI data into a single neuroimaging technique with high spatial and temporal resolution. Two examples of application to brain studies, from our own experience, are also described.

• High-resolution spatio-temporal neuronal activation in the visual oddball task: a simultaneous EEG/fMRI study

  Authors: L. Marzetti, D. Mantini, S. Cugini, G.L. Romani, C. Del Gratta

  Noninvasive Functional Source Imaging of the Brain and Heart and the International Conference on Functional Biomedical Imaging, 2007. NFSI-ICFBI 2007. Joint Meeting of the 6th International Symposium on; 11/2007

  The combined use of EEG and fMRI allows for the fusion of electrophysiological and hemodynamic information in the study of human cognitive functions. In order to investigate cerebral activity duringThe combined use of EEG and fMRI allows for the fusion of electrophysiological and hemodynamic information in the study of human cognitive functions. In order to investigate cerebral activity during a visual oddball task, simultaneous EEG/fMRI recording from 10 healthy subjects was performed. A devoted data-analysis method based on trial-by-trial coupling of concurrent EEG and fMRI for the high-resolution spatio-temporal analysis of P300 neuronal activation was developed. Our results obtained from fMRI data showed the involvement of inferior and medial frontal gyrus, cingulated motor area, middle temporal gyrus, and inferior parietal lobule in the oddball task; furthermore, activations were generally right lateralized, in accordance with previous findings. Using the high temporal resolution of EEG, we could separate neuronal activations specifically related to P300 activity, and therefore study the activation timing. We found that the detection of rare targets, that is able to elicit the P300 component, stimulates a limbic-parietofrontal circuit, with latencies ranging between 300 and 400 ms. Our findings suggest that the proposed approach might be extended to other event-related experimental paradigms, and might represent an valuable tool for a clearer understanding of the cerebral mechanisms underlying a wide range of cognitive functions.

• Fusion of EEG and fMRI for the investigation of functional connectivity during a visual oddball task

  Authors: D. Mantini, S. Cugini, G.L. Romani, C. Del Gratta

  Noninvasive Functional Source Imaging of the Brain and Heart and the International Conference on Functional Biomedical Imaging, 2007. NFSI-ICFBI 2007. Joint Meeting of the 6th International Symposium on; 11/2007

  The combined use of EEG and fMRI allows the fusion of electrophysiological and hemodynamic information for the study of the human brain function. In order to investigate functional connectivityThe combined use of EEG and fMRI allows the fusion of electrophysiological and hemodynamic information for the study of the human brain function. In order to investigate functional connectivity during a visual oddball task, we performed simultaneous EEG/fMRI recording from 14 healthy subjects. A completely data-driven approach, based on trial-by-trial coupling of concurrent EEG and fMRI, was used for the retrieval of cerebral networks linked to P300. An ICA-based analysis of fMRI BOLD data allowed to characterize neuro-anatomically defined patterns, each of them with a definite spatial map and a specific time-course of activation. In addition, we performed single-trial analysis on EEG data, reconstructing the temporal evolution of the P300 amplitude. This time-course, convolved with a canonical HRF, was considered as an estimate of the P300-related activity in the BOLD signals, and allowed to identify two cerebral networks linked to target detection. They showed spatial maps already observed in previous studies, which could be respectively associated with the dorsal attention and the change-detection networks. Time-domain analysis of BOLD data suggested that the attention network might account for sustained activity reflecting amplitude modulations of P300, whereas the change-detection network for transient activity associated with the event-related P300 response.

• From where to how: assessing mechanisms of neural plasticity in patients with unilateral brain lesions

  Authors: P Belardinelli, L Ciancetta, M Staudt, V Pizzella, A Londei, N Birbaumer, G L Romani, C Braun

  Noninvasive Functional Source Imaging of the Brain and Heart and the International Conference on Functional Biomedical Imaging, 2007. NFSI-ICFBI 2007. Joint Meeting of the 6th International Symposium on; 11/2007

  A set of different algorithms was involved to analyze the anomalous motor control in four young hemi-paretic patients with pre-and perinatally acquired brain lesions. The effects of a peculiarA set of different algorithms was involved to analyze the anomalous motor control in four young hemi-paretic patients with pre-and perinatally acquired brain lesions. The effects of a peculiar cerebral reorganization allow the patients to move the paretic arm. Patients performed a pinch grip using their paretic and non-paretic hands alternatively. EMG was simultaneously recorded as a basis for coherence calculations. 3D coherence mapping was performed in the beta frequency range. Such approach evidenced the relocation of motor functions from the lesioned (left) to the contralesional (right) hemisphere. While in case of left, non-paretic pinch grip, coherent activity originated from contralateral (right) Ml exclusively, right (paretic) grip, produced coherent activity in ipsilateral Ml as well as significant coherence of ipsilateral cerebellum. Coupling direction analysis demonstrated that throughout pinch grip the coupling direction goes from Ml to cerebellum.