Vittorio Pizzella

Publications of Vittorio Pizzella

• A signal-processing pipeline for magnetoencephalography resting-state networks.

  Authors: Dante Mantini, Stefania Della Penna, Laura Marzetti, Francesco de Pasquale, Vittorio Pizzella, Maurizio Corbetta, Gian Luca Romani

  Brain connectivity. 01/2011; 1(1):49-59.

  Abstract To study functional connectivity using magnetoencephalographic (MEG) data, the high-quality source-level reconstruction of brain activity constitutes a critical element. MEG resting-stateAbstract To study functional connectivity using magnetoencephalographic (MEG) data, the high-quality source-level reconstruction of brain activity constitutes a critical element. MEG resting-state networks (RSNs) have been documented by means of a dedicated processing pipeline: MEG recordings are decomposed by independent component analysis (ICA) into artifact and brain components (ICs); next, the channel maps associated with the latter ones are projected into the source space and the resulting voxel-wise weights are used to linearly combine the IC time courses. An extensive description of the proposed pipeline is provided here, along with an assessment of its performances with respect to alternative approaches. The following investigations were carried out: (1) ICA decomposition algorithm. Synthetic data are used to assess the sensitivity of the ICA results to the decomposition algorithm, by testing FastICA, INFOMAX, and SOBI. FastICA with deflation approach, a standard solution, provides the best decomposition. (2) Recombination of brain ICs versus subtraction of artifactual ICs (at the channel level). Both the recombination of the brain ICs in the sensor space and the classical procedure of subtracting the artifactual ICs from the recordings provide a suitable reconstruction, with a lower distortion using the latter approach. (3) Recombination of brain ICs after localization versus localization of artifact-corrected recordings. The brain IC recombination after source localization, as implemented in the proposed pipeline, provides a lower source-level signal distortion. (4) Detection of RSNs. The accuracy in source-level reconstruction by the proposed pipeline is confirmed by an improved specificity in the retrieval of RSNs from experimental data.

• Temporal dynamics of spontaneous MEG activity in brain networks.

  Authors: Francesco de Pasquale, Stefania Della Penna, Abraham Z Snyder, Christopher Lewis, Dante Mantini, Laura Marzetti, Paolo Belardinelli, Luca Ciancetta, Vittorio Pizzella, Gian Luca Romani, Maurizio Corbetta

  Proceedings of the National Academy of Sciences of the United States of America. 03/2010; 107(13):6040-5.

  Functional MRI (fMRI) studies have shown that low-frequency (<0.1 Hz) spontaneous fluctuations of the blood oxygenation level dependent (BOLD) signal during restful wakefulness are coherent withinFunctional MRI (fMRI) studies have shown that low-frequency (<0.1 Hz) spontaneous fluctuations of the blood oxygenation level dependent (BOLD) signal during restful wakefulness are coherent within distributed large-scale cortical and subcortical networks (resting state networks, RSNs). The neuronal mechanisms underlying RSNs remain poorly understood. Here, we describe magnetoencephalographic correspondents of two well-characterized RSNs: the dorsal attention and the default mode networks. Seed-based correlation mapping was performed using time-dependent MEG power reconstructed at each voxel within the brain. The topography of RSNs computed on the basis of extended (5 min) epochs was similar to that observed with fMRI but confined to the same hemisphere as the seed region. Analyses taking into account the nonstationarity of MEG activity showed transient formation of more complete RSNs, including nodes in the contralateral hemisphere. Spectral analysis indicated that RSNs manifest in MEG as synchronous modulation of band-limited power primarily within the theta, alpha, and beta bands-that is, in frequencies slower than those associated with the local electrophysiological correlates of event-related BOLD responses.

• Modulation of alpha oscillations in insular cortex reflects the threat of painful stimuli.

  Authors: Raffaella Franciotti, Luca Ciancetta, Stefania Della Penna, Paolo Belardinelli, Vittorio Pizzella, Gian Luca Romani

  NeuroImage. 04/2009;

  Pain is a sensory and emotional experience that involves numerous brain areas. Among these areas the insular cortex has been shown to be involved in the expectation and processing of pain. AlphaPain is a sensory and emotional experience that involves numerous brain areas. Among these areas the insular cortex has been shown to be involved in the expectation and processing of pain. Alpha power modulation has been associated with the experience of pain. The aim of this study was to test the hypothesis that the threat of a painful stimulus affects alpha rhythm oscillation in the insular cortex and to find the time intervals during which the insular cortex is most active. We used a beamforming method in the frequency domain to estimate alpha power associated with source activity during psychologically different conditions, namely a sequence of nonpainful somatosensory stimuli (non-threatening condition) and a sequence of nonpainful stimuli randomly intermixed with painful stimuli (threatening condition). The results revealed that the anterior insula alone was involved during the threat of painful stimuli. Conversely, the posterior insula - as well as other brain areas such as SII - was involved in the processing of somatosensory stimuli regardless their painfulness. Additionally, the involvement of the anterior insula should not be accounted for by fear, arousal, habituation effect or by the occurrence of randomly interleaved different stimuli, but it is likely to be related mainly to expectancy mechanisms enhancing activity of specific neuronal populations.

• Chapter 5 fundamentals of electroencefalography, magnetoencefalography, and functional magnetic resonance imaging.

  Authors: Claudio Babiloni, Vittorio Pizzella, Cosimo Del Gratta, Antonio Ferretti, Gian Luca Romani

  International review of neurobiology. 01/2009; 86:67-80.

  This review introduces readers to fundamentals of electroencephalography (EEG), magnetoencephalography (MEG), and functional magnetic resonance imaging (fMRI). EEG and MEG signals are mainly producedThis review introduces readers to fundamentals of electroencephalography (EEG), magnetoencephalography (MEG), and functional magnetic resonance imaging (fMRI). EEG and MEG signals are mainly produced by postsynaptic ionic currents of synchronically active pyramidal cortical neurons. These signals reflect the integrative information processing of neurons representing the output of cortical neural modules. EEG and MEG signals have a high temporal resolution (<1ms) ideal to investigate an emerging propriety of brain physiology, namely the brain rhythms. A background spontaneous oscillatory activity of brain neurons at about 10Hz generates dominant alpha rhythms of resting-state EEG and MEG activity. This background activity is blocked during sensory and cognitive-motor events. Standard EEG shows a low spatial resolution (5-9cm), which partially improves by high-resolution EEG including 64-128 channels and source estimation techniques (1-3cm); source estimation of MEG data shows a better spatial resolution (0.5-2cm). fMRI is an indirect measurement of regional brain activity based on the ratio between deoxyhemoglobin and oxyhemoglobin blood (BOLD) during events referenced to baseline conditions. Event-related BOLD response has low temporal resolution (>1s) and quite high spatial resolution (<1cm), and is especially suitable to investigate spatial details of both cortical and subcortical activation.

• Neuromagnetic functional coupling during dichotic listening of speech sounds.

  Authors: Alfredo Brancucci, Stefania Della Penna, Claudio Babiloni, Fabrizio Vecchio, Paolo Capotosto, Davide Rossi, Raffaella Franciotti, Kathya Torquati, Vittorio Pizzella, Paolo M Rossini, Gian Luca Romani

  Human brain mapping. 04/2008; 29(3):253-64.

  The present magnetoencephalography (MEG) study tested the hypothesis of a phase synchronization (functional coupling) of cortical alpha rhythms (about 6-12 Hz) within a "speech" cortical neuralThe present magnetoencephalography (MEG) study tested the hypothesis of a phase synchronization (functional coupling) of cortical alpha rhythms (about 6-12 Hz) within a "speech" cortical neural network comprising bilateral primary auditory cortex and Wernicke's areas, during dichotic listening (DL) of consonant-vowel (CV) syllables. Dichotic stimulation was done with the CV-syllable pairs /da/-/ba/ (true DL, yielded by stimuli having high spectral overlap) and /da/-/ka/ (sham DL, obtained with stimuli having poor spectral overlap). Whole-head MEG activity (165 sensors) was recorded from 10 healthy right-handed non-musicians showing right ear advantage in a speech DL task. Functional coupling of alpha rhythms was defined as the spectral coherence at the following bands: alpha 1 (about 6-8 Hz), alpha 2 (about 8-10 Hz), and alpha 3 (about 10-12) with respect to the peak of individual alpha frequency. Results showed an inverse pattern of functional coupling: during DL of speech sounds, spectral coherence of the high-band alpha rhythms increased between left auditory and Wernicke's areas with respect to sham DL, whereas it decreased between left and right auditory areas. The increase of functional coupling within the left hemisphere would underlie the processing of the syllable presented to the right ear, which arrives to the left auditory cortex without the interference of the other syllable presented to the left ear. Conversely, the decrease of inter-hemispherical coupling of the high-band alpha might be due to the fact that the two auditory cortices do not receive the same information from the ears during DL. These results suggest that functional coupling of alpha rhythms can constitute a neural substrate for the lateralization of auditory stimuli during DL.

• Functional source separation applied to induced visual gamma activity.

  Authors: Giulia Barbati, Camillo Porcaro, Avgis Hadjipapas, Peyman Adjamian, Vittorio Pizzella, Gian Luca Romani, Stefano Seri, Franca Tecchio, Gareth R Barnes

  Human brain mapping. 02/2008; 29(2):131-41.

  Objective of this work was to explore the performance of a recently introduced source extraction method, FSS (Functional Source Separation), in recovering induced oscillatory change responses fromObjective of this work was to explore the performance of a recently introduced source extraction method, FSS (Functional Source Separation), in recovering induced oscillatory change responses from extra-cephalic magnetoencephalographic (MEG) signals. Unlike algorithms used to solve the inverse problem, FSS does not make any assumption about the underlying biophysical source model; instead, it makes use of task-related features (functional constraints) to estimate source/s of interest. FSS was compared with blind source separation (BSS) approaches such as Principal and Independent Component Analysis, PCA and ICA, which are not subject to any explicit forward solution or functional constraint, but require source uncorrelatedness (PCA), or independence (ICA). A visual MEG experiment with signals recorded from six subjects viewing a set of static horizontal black/white square-wave grating patterns at different spatial frequencies was analyzed. The beamforming technique Synthetic Aperture Magnetometry (SAM) was applied to localize task-related sources; obtained spatial filters were used to automatically select BSS and FSS components in the spatial area of interest. Source spectral properties were investigated by using Morlet-wavelet time-frequency representations and significant task-induced changes were evaluated by means of a resampling technique; the resulting spectral behaviours in the gamma frequency band of interest (20-70 Hz), as well as the spatial frequency-dependent gamma reactivity, were quantified and compared among methods. Among the tested approaches, only FSS was able to estimate the expected sustained gamma activity enhancement in primary visual cortex, throughout the whole duration of the stimulus presentation for all subjects, and to obtain sources comparable to invasively recorded data.

• Lateralization of dichotic speech stimuli is based on specific auditory pathway interactions: neuromagnetic evidence.

  Authors: Stefania Della Penna, Alfredo Brancucci, Claudio Babiloni, Raffaella Franciotti, Vittorio Pizzella, Davide Rossi, Kathya Torquati, Paolo M Rossini, Gian Luca Romani

  Cerebral cortex (New York, N.Y. : 1991). 11/2007; 17(10):2303-11.

  Dichotic listening (DL) is a neuropsychological technique for the study of functional laterality. Based on behavioral patient studies, the "structural theory" states that lateralization of theDichotic listening (DL) is a neuropsychological technique for the study of functional laterality. Based on behavioral patient studies, the "structural theory" states that lateralization of the auditory input during DL is allowed by an inhibition of the ipsilateral pathways. We aimed here at extending this theory to provide a neurophysiological basis of verbal DL. We investigated the magnetic responses of the primary auditory cortices elicited by dichotic consonant-vowel syllables. Dichotic stimuli consisted of 2 syllables pairs, a "competing" one composed by syllables with high spectral overlap (/da/ and /ba/) and a "noncompeting" pair (/da/ and /ka/). One of the syllables in each pair was delivered at 2 intensities, whereas the other did not change. A reduced increase of source intensity in response to dichotic pairs at the 2 levels was assumed to indicate pathway inhibition effects. We obtained that the left ipsilateral pathway (i.e., the left ipsilateral signal) was strongly inhibited by the right contralateral one. Conversely, the right ipsilateral pathway did not show an inhibition larger than the left contralateral one. These results extend the notion of auditory functional asymmetries by showing that beyond hemispheric functional specialization there is an asymmetry within the ascending auditory system, which is based on a competition mechanism. The larger the competition between the left and right ear stimuli, the larger are the inhibition effects, which determine the pathway asymmetry. These findings represent as well a neurophysiological basis for the "structural theory" explaining the right ear preference usually found in verbal DL tasks.

• Temporal dynamics of plastic changes in human primary somatosensory cortex after finger webbing.

  Authors: Maria L Stavrinou, Stefania Della Penna, Vittorio Pizzella, Kathya Torquati, Francesco Cianflone, Raffaella Franciotti, Anastasios Bezerianos, Gian Luca Romani, Paolo Maria Rossini

  Cerebral cortex (New York, N.Y. : 1991). 10/2007; 17(9):2134-42.

  The primary somatosensory cortex (SI) exhibits a detailed topographic organization of the hand and fingers, which has been found to undergo plastic changes following modifications of the sensoryThe primary somatosensory cortex (SI) exhibits a detailed topographic organization of the hand and fingers, which has been found to undergo plastic changes following modifications of the sensory input. Although the spatial properties of these changes have been extensively investigated, little is known about their temporal dynamics. In this study, we adapted the paradigm of finger webbing, in which 4 fingers are temporarily webbed together, hence modifying their sensory feedback. We used magnetoencephalography, to measure changes in the hand representation in SI, before, during, and after finger webbing for about 5 h. Our results showed a decrease in the Euclidean distance (ED) between cortical sources activated by electrical stimuli to the index and small finger 30 min after webbing, followed by an increase lasting for about 2 h after webbing, which was followed by a return toward baseline values. These results provide a unique frame in which the different representational changes occur, merging previous findings that were only apparently controversial, in which either increases or decreases in ED were reported after sensory manipulation for relatively long or short duration, respectively. Moreover, these observations further confirm that the mechanisms that underlie cortical reorganization are extremely rapid in their expression and, for the first time, show how brain reorganization occurs over time.

• fMRI-vs-MEG evaluation of post-stroke interhemispheric asymmetries in primary sensorimotor hand areas.

  Authors: Claudia Altamura, Kahtya Torquati, Filippo Zappasodi, Antonio Ferretti, Vittorio Pizzella, Francesco Tibuzzi, Fabrizio Vernieri, Patrizio Pasqualetti, Doriana Landi, Cosimo Del Gratta, Gian Luca Romani, Paolo Maria Rossini, Franca Tecchio

  Experimental neurology. 05/2007; 204(2):631-9.

  Growing evidence emphasizes a positive role of brain ipsilesional (IL) reorganization in stroke patients with partial recovery. Ten patients affected by a monohemispheric stroke in the middleGrowing evidence emphasizes a positive role of brain ipsilesional (IL) reorganization in stroke patients with partial recovery. Ten patients affected by a monohemispheric stroke in the middle cerebral artery territory underwent functional magnetic resonance (fMRI) and magnetoencephalography (MEG) evaluation of the primary sensory (S1) activation via the same paradigm (median nerve galvanic stimulation). Four patients did not present S1 fMRI activation [Rossini, P.M., Altamura, C., Ferretti, A., Vernieri, F., Zappasodi, F., Caulo, M., Pizzella, V., Del Gratta, C., Romani, G.L., Tecchio, F., 2004. Does cerebrovascular disease affect the coupling between neuronal activity and local haemodynamics? Brain 127, 99-110], although inclusion criteria required bilateral identifiable MEG responses. Mean Euclidean distance between fMRI and MEG S1 activation Talairach coordinates was 10.1+/-2.9 mm, with a 3D intra-class correlation (ICC) coefficient of 0.986. Interhemispheric asymmetries, evaluated by an MEG procedure independent of Talairach transformation, were outside or at the boundaries of reference ranges in 6 patients. In 3 of them, the IL activation presented medial or lateral shift with respect to the omega-shaped post-rolandic area while in the other 3, IL areas were outside the peri-rolandic region. In conclusion, despite dissociated intensity, the MEG and fMRI activations displayed good spatial consistency in stroke patients, thus confirming excessive interhemispheric asymmetries as a suitable indicator of unusual recruitments in the ipsilesional hemisphere, within or outside the peri-rolandic region.

• Sequential Activation of Human Oculomotor Centers During Planning of Visually-Guided Eye Movements: A Combined fMRI-MEG Study.

  Authors: Carlo Sestieri, Vittorio Pizzella, Francesco Cianflone, Gian Luca Romani, Maurizio Corbetta

  Frontiers in human neuroscience. 02/2007; 1:1.

  We used magneto-encephalography (MEG) to measure visually evoked activity in healthy volunteers performing saccadic eye movements to visual targets. The neuromagnetic activity was analyzed fromWe used magneto-encephalography (MEG) to measure visually evoked activity in healthy volunteers performing saccadic eye movements to visual targets. The neuromagnetic activity was analyzed from regions of cortical activation identified in separate functional magnetic resonance imaging (fMRI) studies. The latency of visual responses significantly increased from the Middle Temporal region (MT+) to the Intraparietal Sulcus (IPS) to the Frontal Eye Field (FEF), and their amplitude was greater in the hemisphere contralateral to the visual target. Trial-to-trial variability of oculomotor reaction times correlated with visual response latency across cortical areas. These results support a feedforward recruitment of oculomotor cortical centers by visual information, and a model in which behavioral variability depends on variability at different neural stages of processing.

• Brain plasticity in recovery from stroke: an MEG assessment.

  Authors: Franca Tecchio, Filippo Zappasodi, Mario Tombini, Antonio Oliviero, Patrizio Pasqualetti, Fabrizio Vernieri, Matilde Ercolani, Vittorio Pizzella, Paolo Maria Rossini

  NeuroImage. 10/2006; 32(3):1326-34.

  The aim of this paper was to deepen understanding about the role played by brain plasticity in obtaining clinical recovery. Eighteen patients, who had recovered partially or totally from dysfunctionsThe aim of this paper was to deepen understanding about the role played by brain plasticity in obtaining clinical recovery. Eighteen patients, who had recovered partially or totally from dysfunctions due to a monohemispheric infarction within the middle cerebral artery territory, underwent magnetoencephalographic (MEG) recordings of rolandic areas cerebral activity both in rest state (spectral power properties) and in response to the electrical stimulation of the contralateral median nerve (M20 and M30 cortical sources). MEG evaluation was performed in acute (T0: mean 5 days from ischemic attach) and post-acute phase (T1: median 6 months). At T1, all the inter-hemispheric asymmetries were reduced for both spontaneous and evoked activity parameters with respect to T0. In post-acute phase, lower cortical excitability, higher delta and theta power and lower spectral entropy were associated to a worse clinical state. An unusual recruitment-as revealed by an excessive inter-hemispheric asymmetry of M20 cortical source position-correlated with higher level of clinical amelioration in the patients who showed a partial recovery. In addition to confirmative evidence that "normalization" of neural activity in both the affected and unaffected hemispheres subtends best clinical recovery, present data provide support to the positive role of cerebral plasticity phenomena--i.e. unusual neural recruitments--to regain lost functions in those patients unable to achieve total recovery.

• Hand cortical representation at rest and during activation: gender and age effects in the two hemispheres.

  Authors: Filippo Zappasodi, Patrizio Pasqualetti, Mario Tombini, Matilde Ercolani, Vittorio Pizzella, Paolo M Rossini, Franca Tecchio

  Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology. 08/2006; 117(7):1518-28.

  OBJECTIVE: To characterize the age- and gender- dependence of sensory hand cortical representation in the two hemispheres in healthy population. METHODS: In 57 adults, the cerebral activity fromOBJECTIVE: To characterize the age- and gender- dependence of sensory hand cortical representation in the two hemispheres in healthy population. METHODS: In 57 adults, the cerebral activity from rolandic areas as detected by magnetoencephalography was considered both in a resting state (spectral power properties) and in response to the electrical stimulation of the contralateral median nerve (M20 and M30 cortical sources). RESULTS: We found a dependence of rest and evoked activity on age (alpha rhythm slowing, high frequency power increase, M20 latency increase, M20 strength increase, no change in M30) and on gender (higher alpha frequency, higher beta power, higher spectral entropy, lower M20 amplitude in women). These changes were quite symmetrical in the two hemispheres, making the interhemispheric differences non-dependent on age and gender. Moreover, lower total power and faster alpha rhythm appeared in the dominant hemisphere. CONCLUSIONS: Age and gender have a significant effect on spontaneous and evoked activity at the primary sensorimotor cortex. SIGNIFICANCE: The results consolidate the reference base in healthy population, to study pathological conditions. Inter-hemispheric asymmetries are confirmed as a sensitive indicator for the early identification of possible neuronal rearrangements due to unilateral brain injuries.

• Fetal auditory responses to external sounds and mother's heart beat: detection improved by Independent Component Analysis.

  Authors: Camillo Porcaro, Filippo Zappasodi, Giulia Barbati, Carlo Salustri, Vittorio Pizzella, Paolo Maria Rossini, Franca Tecchio

  Brain research. 08/2006; 1101(1):51-8.

  In this paper, we present a magnetoencephalographic study of the fetal auditory response to external stimuli and to the sound of the mother's heartbeat. We describe how an ad hoc functional selectionIn this paper, we present a magnetoencephalographic study of the fetal auditory response to external stimuli and to the sound of the mother's heartbeat. We describe how an ad hoc functional selection procedure allowed us to isolate the sources in the fetal brain responding to sounds only, after the application to the recorded data of a standard Independent Component Analysis algorithm. In our experiment, acoustic stimuli were delivered to twelve healthy women with uncomplicated pregnancies at a time between 36 and 40 weeks gestational age, with their fetuses in breech presentation. Ultrasound images allowed determination of the region over the women's abdomen nearest to the fetal head, over which both the acoustic stimulator and the MEG sensors were subsequently placed. In 8 out of the 12 cases, our analysis provided consistent evidence of a fetal response both to the mother's heartbeat and to the external auditory stimulation; both were characterized by a clear prominent component at around 200 ms latency, which is widely accepted as the marker of the fetal response to auditory stimuli.

• Rhythmic brain activity at rest from rolandic areas in acute mono-hemispheric stroke: a magnetoencephalographic study.

  Authors: Franca Tecchio, Filippo Zappasodi, Patrizio Pasqualetti, Mario Tombini, Carlo Salustri, Antonio Oliviero, Vittorio Pizzella, Fabrizio Vernieri, Paolo Maria Rossini

  NeuroImage. 11/2005; 28(1):72-83.

  In order to deepen our knowledge of the brain's ability to react to a cerebral insult, it is fundamental to obtain a "snapshot" of the acute phase, both for understanding the neural conditionIn order to deepen our knowledge of the brain's ability to react to a cerebral insult, it is fundamental to obtain a "snapshot" of the acute phase, both for understanding the neural condition immediately after the insult and as a starting point for follow-up and clinical outcome prognosis. The characteristics of the brain's spontaneous neuronal activity in perirolandic cortical areas were investigated in 32 patients who had a stroke in the middle cerebral artery (MCA) territory of one hemisphere in the previous 10 days. Magnetic fields from both left and right rolandic areas were recorded at rest with open eyes. Total and band power properties, the individual alpha frequency (IAF) and the spectral entropy were analyzed and compared with a sex-age matched control group. In agreement with electroencephalographic literature, low frequency absolute powers were higher and high frequency were lower in the affected (AH) than in the unaffected hemisphere (UH), and also their values in both hemispheres differed from control values. An IAF reduction was found in AH with respect to UH. As new findings, the total power was higher in AH than in UH, after excluding 4 right-damaged patients with cortico-subcortical lesions, who showed a completely disorganized spectral pattern. Spectral entropy was lower in AH than in UH. Clinical severity correlated with the AH decrease of gamma band power, IAF and spectral entropy. Larger lesions were associated to worse clinical pictures and MEG alterations. A lesion affecting the MCA territory of one hemisphere induces a perilesional increase of the low-frequency rhythms' spectral power within the AH rolandic areas; the same effect was present also in the UH, indicating interhemispheric diaschisis. In the AH, results showed an increase of the total power and a reduction of the spectral entropy, suggesting a higher synchrony of local neuronal activity, a reduction of the intra-cortical inhibitory networks efficiency and an increase of neuronal excitability. Direct correlation linked gamma band activity preservation and less severe clinical status. Dependence of the clinical picture, and associated spectral alterations, on the lesion volume and not on the lesion level, suggests a diffuse neuronal impairment, rather than a selective structures damage, contributing to neurological status in the acute phase of stroke.

• Dynamics of male sexual arousal: distinct components of brain activation revealed by fMRI.

  Authors: Antonio Ferretti, Massimo Caulo, Cosimo Del Gratta, Rosalia Di Matteo, Arcangelo Merla, Francesco Montorsi, Vittorio Pizzella, Paolo Pompa, Patrizio Rigatti, Paolo Maria Rossini, Andrea Salonia, Armando Tartaro, Gian Luca Romani

  NeuroImage. 08/2005; 26(4):1086-96.

  The peripheral mechanisms of male sexual arousal are well known. Recently, neuroimaging techniques, such as PET or fMRI, allowed the investigation of the subjacent cerebral mechanisms. In ten healthyThe peripheral mechanisms of male sexual arousal are well known. Recently, neuroimaging techniques, such as PET or fMRI, allowed the investigation of the subjacent cerebral mechanisms. In ten healthy subjects, we have simultaneously recorded fMRI images of brain activation elicited by viewing erotic scenes, and the time course of penile tumescence by means of a custom-built MRI-compatible pneumatic cuff. We have compared activation elicited by video clips with a long duration, that led to sexual arousal and penile erection, and activation elicited by briefly presented still images, that did induce sexual arousal without erection. This comparison and the use of the time course of penile tumescence in video clips allowed to perform a time resolved data analysis and to correlate different patterns of brain activation with different phases of sexual response. The activation maps highlighted a complex neural circuit involved in sexual arousal. Of this circuit, only a few areas (anterior cingulate, insula, amygdala, hypothalamus, and secondary somatosensory cortices) were specifically correlated with penile erection. Finally, these areas showed distinct dynamic relationships with the time course of sexual response. These differences might correspond to different roles in the development and appraisal of the sexual response. These findings shed light on the psychophysiology of male sexuality and open new perspectives for the diagnosis, therapy, and possible rehabilitation of sexual dysfunction.

• Alpha rhythms in mild dements during visual delayed choice reaction time tasks: a MEG study.

  Authors: Claudio Babiloni, Emanuele Cassetta, Paola Chiovenda, Claudio Del Percio, Matilde Ercolani, Davide Vito Moretti, Filomena Moffa, Patrizio Pasqualetti, Vittorio Pizzella, Gian Luca Romani, Franca Tecchio, Filippo Zappasodi, Paolo Maria Rossini

  Brain research bulletin. 06/2005; 65(6):457-70.

  Can simple delayed response tasks affect latency and amplitude of magnetoencephalographic midline alpha rhythms (6-12 Hz) in early dementia? We recruited 15 mild Alzheimer's disease (AD) and 10Can simple delayed response tasks affect latency and amplitude of magnetoencephalographic midline alpha rhythms (6-12 Hz) in early dementia? We recruited 15 mild Alzheimer's disease (AD) and 10 vascular dementia (VaD) patients (paired mini mental state exam of 17-24). The control groups comprised 18 young and 22 elderly normal subjects. In the first task, a simple "cue" stimulus (one bit) was memorized along a brief delay period (3.5-5.5s) up to a "go" stimulus triggering (right or left) button press. In the second task, the "cue" stimulus remained available along the delay period. Event-related reduction in power of the alpha rhythms indexed the cortical activation (event-related desynchronization, ERD) for the trials associated with correct behavioral responses. Behavioral performances to both tasks were lower in the AD and VaD patients than in the normal subjects. In particular, just four AD and five VaD patients executed a sufficient amount of correct responses for the alpha ERD analysis, so they were included in a unique group. In both tasks, the alpha ERD peak was later in latency in the demented and normal elderly subjects than in the normal young subjects. Furthermore, the alpha ERD peak was stronger in amplitude in the demented patients than in the normal subjects. These results suggest that simple delayed response tasks during physiological recordings are quite difficult for patients even at an early dementia stage. Such difficulty may induce the abnormal amount of the related cortical activation in dementia as revealed by the alpha ERD.

• Contingent negative variation in the parasylvian cortex increases during expectancy of painful sensorimotor events: a magnetoencephalographic study.

  Authors: Claudio Babiloni, Alfredo Brancucci, Vittorio Pizzella, Gian Luca Romani, Franca Tecchio, Kathya Torquati, Filippo Zappasodi, Lars Arendt-Nielsen, Andrew C N Chen, Paolo Maria Rossini

  Behavioral neuroscience. 05/2005; 119(2):491-502.

  Previous evidence relating to somatosensory-evoked magnetic fields has shown that the human parasylvian cortex (PC) is affected by ongoing painful sensorimotor interactions. In the presentPrevious evidence relating to somatosensory-evoked magnetic fields has shown that the human parasylvian cortex (PC) is affected by ongoing painful sensorimotor interactions. In the present magnetoencephalographic study, the activity of the PC was investigated to evaluate the hypothesis of anticipatory processes preceding painful sensorimotor interactions. Sensorimotor interactions were induced by warned painful electrical stimulations at the left hand concomitant with a motor task of the right hand. The anticipatory activity of the PC was probed via contingent negative variation. Compared with the control nonpainful condition, the anticipation of the painful sensorimotor interactions increased the PC activity over the hemisphere ipsilateral to the stimulation. Dipole modeling indicated that the center of gravity of the anticipatory activity in the PC was located in the secondary somatosensory cortex. These results suggest that anticipation of painful sensorimotor interactions engages the human PC, especially in the hemisphere ipsilateral to upcoming painful stimuli and contralateral to preparatory motor commands.

• Human alpha rhythms during visual delayed choice reaction time tasks: a magnetoencephalography study.

  Authors: Claudio Babiloni, Fabio Babiloni, Filippo Carducci, Febo Cincotti, Claudio Del Percio, Stefania Della Penna, Raffaella Franciotti, Sandro Pignotti, Vittorio Pizzella, Paolo Maria Rossini, Elisabetta Sabatini, Kathya Torquati, Gian Luca Romani

  Human brain mapping. 04/2005; 24(3):184-92.

  Magnetoencephalography (MEG) includes fast and comfortable recording procedures very suitable for the neurophysiological study of cognitive functions in aged people. In this exploratory MEG study inMagnetoencephalography (MEG) includes fast and comfortable recording procedures very suitable for the neurophysiological study of cognitive functions in aged people. In this exploratory MEG study in normal young adults, we tested whether very simple short-term memory (STM) demands induce visible changes in amplitude and latency of surface alpha rhythms. Two delayed response tasks were used. In the STM condition, a simple cue stimulus (one bit) was memorized along a brief delay period (3.5-5.5 s). In the control (no short-term memory; NSTM) condition, the cue stimulus remained available along the delay period. To make extremely simple the tasks, the explicit demand was visuospatial but the retention could be also based on phonological and somatomotor coding. Compared to the control condition, the amplitude of the alpha 1 (6-8 Hz) ERD decreased in the left hemisphere, whereas the amplitude of the alpha 2 (8-10 Hz) and alpha 3 (10-12 Hz) event-related desynchronization (ERD) increased in right and left parietal areas, respectively. Furthermore, the latency of the alpha ERD peak was slightly but significantly (P < 0.05) later in STM compared to control condition. In conclusion, whole-head MEG technology and very simple STM demands revealed significant changes of human neuromagnetic alpha rhythms in normal young adults.

• Inhibition of auditory cortical responses to ipsilateral stimuli during dichotic listening: evidence from magnetoencephalography.

  Authors: Alfredo Brancucci, Claudio Babiloni, Fabio Babiloni, Silvana Galderisi, Armida Mucci, Franca Tecchio, Filippo Zappasodi, Vittorio Pizzella, Gian Luca Romani, Paolo Maria Rossini

  The European journal of neuroscience. 05/2004; 19(8):2329-36.

  The present magnetoencephalography (MEG) study on auditory evoked magnetic fields (AEFs) was aimed at verifying whether during dichotic listening the contralateral auditory pathway inhibits theThe present magnetoencephalography (MEG) study on auditory evoked magnetic fields (AEFs) was aimed at verifying whether during dichotic listening the contralateral auditory pathway inhibits the ipsilateral one, as suggested by behavioural and patient studies. Ten healthy subjects were given a randomized series of three complex tones (261, 293 and 391 Hz, 500 ms duration), which were delivered monotically and dichotically with different intensities [60, 70 or 80 dBA (audio decibels)]. MEG data were recorded from the right auditory cortex. Results showed that the M100 amplitude over the right auditory cortex increased progressively when tones of increasing intensity were provided at the ipsilateral (right) ear. This effect on M100 was abolished when a concurrent tone of constant intensity was delivered dichotically at the contralateral (left) ear, suggesting that the contralateral pathway inhibited the ipsilateral one. The ipsilateral inhibition was present only when the contralateral tone fundamental frequency was similar to the ipsilateral tone. It was proposed that the occlusion mechanism would be exerted in cortical auditory areas as the dichotic effects were observed at M100 but not M50 component. This is the first evidence showing a neurophysiological inhibition driven by the contralateral auditory pathway over the ipsilateral one during dichotic listening.

• Gamma synchronization in human primary somatosensory cortex as revealed by somatosensory evoked neuromagnetic fields.

  Authors: Franca Tecchio, Claudio Babiloni, Filippo Zappasodi, Fabrizio Vecchio, Vittorio Pizzella, Gian Luca Romani, Paolo Maria Rossini

  Brain research. 11/2003; 986(1-2):63-70.

  Cortical sensory neurons synchronize their activity at multiple frequency bands after an external stimulation. In the somatosensory cortical areas, previous reports describe more discrete andCortical sensory neurons synchronize their activity at multiple frequency bands after an external stimulation. In the somatosensory cortical areas, previous reports describe more discrete and somatotopically specific neural synchronization at the gamma band. Therefore, an efficient gamma synchronization of the neurons in primary somatosensory cortex (S1) may be expected to characterize the stimulus processing from the thumb, i.e. the hand's most skillful area. To test this hypothesis, neuromagnetic fields were evoked over human S1 by the electrical stimulation of the contralateral thumb or little finger. Neuronal synchronization was indexed by the spectral coherence of the evoked neuromagnetic fields overlying S1. The frequencies of interest were the beta (16-32 Hz) and gamma (36-46 Hz) bands. The global amount of the coherence was defined as the total event-related coherence (ERCoh) among all magnetic sensors overlying the S1. Results showed prevalent increment of beta ERCoh (20-32 Hz) after the little finger stimulation and of gamma ERCoh (36-44 Hz) after the thumb stimulation. These results suggest that the neural synchronization in S1, as revealed by the ERCoh, may vary in frequency as a function of the finger stimulated. In this framework, the neural synchronization at gamma band may characterize the cortical representation of thumb, functionally prevalent with respect to little finger in humans.