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Optimal motor performance requires the monitoring of sensorimotor input to ensure that the motor output matches current intentions. The brain is thought to be equipped with a “comparator” system, which monitors and detects the congruence between intended and actual movement; results of such a comparison can reach awareness. This study explored in healthy participants whether the cathodal transcranial direct current stimulation (tDCS) of the right premotor cortex (PM) and right posterior parietal cortex (PPC) can disrupt performance monitoring in a skilled motor task. Before and after tDCS, participants underwent a two-digit sequence motor task; in post-tDCS session, single-pulse TMS (sTMS) was applied to the right motor cortex, contralateral to the performing hand, with the aim of interfering with motor execution. Then, participants rated on a five-item questionnaire their performance at the motor task. Cathodal tDCS of PM (but not sham or PPC tDCS) impaired the participants’ ability to evaluate their motor performance reliably, making them unconfident about their judgments. Congruently with the worsened motor performance induced by sTMS, participants reported to have committed more errors after sham and PPC tDCS; such a correlation was not significant after PM tDCS. In line with current computational and neuropsychological models of motor control and awareness, the present results show that a mechanism in the PM monitors and compares intended versus actual movements, evaluating their congruence. Cathodal tDCS of the PM impairs the activity of such a “comparator,” disrupting self-confidence about own motor performance.

Recent neuropsychological evidence suggests that acquired brain lesions can, in some instances, abolish the ability to integrate inputs from different sensory modalities, disrupting multisensory perception. We explored the ability to perceive multisensory events, in particular the integrity of audio-visual processing in the temporal domain, in brain-damaged patients with visual field defects (VFD), or with unilateral spatial neglect (USN), by assessing their sensitivity to the 'Sound-Induced Flash Illusion' (SIFI). The study yielded two key findings. Firstly, the 'fission' illusion (namely, seeing multiple flashes when a single flash is paired with multiple sounds) is reduced in both left- and right-brain-damaged patients with VFD, but not in right-brain-damaged patients with left USN. The disruption of the fission illusion is proportional to the extent of the occipital damage. Secondly, a reliable 'fusion' illusion (namely, seeing less flashes when a single sound is paired with multiple flashes) is evoked in USN patients, but neither in VFD patients nor in healthy participants. A control experiment showed that the fusion, but not the fission, illusion is lost in older participants (>50 year-old), as compared with younger healthy participants (<30 year-old). This evidence indicates that the fission and fusion illusions are dissociable multisensory phenomena, altered differently by impairments of visual perception (i.e. VFD) and spatial attention (i.e. USN). The occipital cortex represents a key cortical site for binding auditory and visual stimuli in the SIFI, while damage to right-hemisphere areas mediating spatial attention and awareness does not prevent the integration of audio-visual inputs in the temporal domain.

Aphasia is a common consequence of stroke; it is estimated that about two-thirds of aphasic patients will develop depression in the first year after the stroke. Treatment of post-stroke depression (PSD) is challenging due to the adverse effects of pharmacotherapy and difficulties in evaluating clinical outcomes, including aphasia. Transcranial direct current stimulation (tDCS) is a novel treatment that may improve clinical outcomes in the traditionally pharmacotherapy-refractory PSD. Our aim was to evaluate the safety and efficacy of tDCS for patients with PSD and with aphasia. The Stroke Aphasic Depression Questionnaire (SADQ) and the Aphasic Depression Rating Scale (ADRS) were used to evaluate the severity of PSD. The diagnoses of PSD and aphasia were confirmed by a psychiatrist and a speech-language pathologist, respectively. In this open case series, patients (n = 4) received 10 sessions (once a day) of bilateral tDCS to the dorsolateral prefrontal cortex (DLPFC) and two additional sessions after two and four weeks, for a total of 12 sessions. All patients exhibited improvement in depression after tDCS, as indicated by a decrease in SADQ (47.5%) and in ADRS (65.7%). This improvement was maintained four weeks after the treatment. In this preliminary, open-label study conducted in four PSD patients with aphasia, bilateral tDCS over the DLPFC was shown to induce a substantial mood improvement; tDCS was safe and well tolerated by every patient. Stroke patients with aphasia can be safely treated for PSD with tDCS. Sham-controlled studies are necessary to evaluate this technique further.

When someone looses one type of sensory input, s/he may compensate by using the sensory information conveyed by other senses. To verify whether loosing a sense or two has consequences on a spared sensory modality, namely touch, and whether these consequences depend on the type of sensory loss, we investigated the effects of deafness and blindness on temporal and spatial tactile tasks in deaf, blind and deaf-blind people. Deaf and deaf-blind people performed the spatial tactile task better than the temporal one, while blind and controls showed the opposite pattern. Deaf and deaf-blind participants were impaired in temporal discrimination as compared to controls, while deaf-blind individuals outperformed blind participants in the spatial tactile task. Overall, sensory-deprived participants did not show an enhanced tactile performance. We speculate that discriminative touch is not so relevant in humans, while social touch is. Probably, more complex tactile tasks would have revealed an increased performance in sensory-deprived people.

Cognitive rehabilitation is an important area of neurological rehabilitation, which aims at the treatment of cognitive disorders due to acquired brain damage of different etiology, including stroke. Although the importance of cognitive rehabilitation for stroke survivors is well recognized, available cognitive treatments for neuropsychological disorders, such as spatial neglect, hemianopia, apraxia, and working memory, are overall still unsatisfactory. The growing body of evidence supporting the potential of the transcranial Electrical Stimulation (tES) as tool for interacting with neuroplasticity in the human brain, in turn for enhancing perceptual and cognitive functions, has obvious implications for the translation of this noninvasive brain stimulation technique into clinical settings, in particular for the development of tES as adjuvant tool for cognitive rehabilitation. The present review aims at presenting the current state of art concerning the use of tES for the improvement of post-stroke visual and cognitive deficits (except for aphasia and memory disorders), showing the therapeutic promises of this technique and offering some suggestions for the design of future clinical trials. Although this line of research is still in infancy, as compared to the progresses made in the last years in other neurorehabilitation domains, current findings appear very encouraging, supporting the development of tES for the treatment of post-stroke cognitive impairments.

In everyday life, many diverse bits of information, simultaneously derived from the different sensory channels, converge into discrete brain areas, and are ultimately synthetized into unified percepts. Such multisensory integration can dramatically alter the phenomenal experience of both environmental events and our own body. Crossmodal illusions are one intriguing product of multisensory integration. This review describes and discusses the main clinical applications of the most known crossmodal illusions in rehabilitation settings. We consider evidence highlighting the contribution of crossmodal illusions to restore, at least in part, defective mechanisms underlying a number of disorders of body representation related to pain, sensory, and motor impairments in neuropsychological and neurological diseases, and their use for improving neuroprosthetics. This line of research is enriching our understanding of the relationships between multisensory functions and the pathophysiological mechanisms at the basis of a number of brain disorders. The review illustrates the potential of crossmodal illusions for restoring disarranged spatial and body representations, and, in turn, different pathological symptoms.

The sense of touch provides fundamental information about the surrounding world, and feedback about our own actions. Although touch is very important during the earliest stages of life, to date no study has investigated infants' abilities to process visual stimuli implying touch. This study explores the developmental origins of the ability to visually recognize touching gestures involving others. Looking times and orienting responses were measured in a visual preference task, in which participants were simultaneously presented with two videos depicting a touching and a no-touching gesture involving human body parts (face, hand) and/or an object (spoon). In Experiment 1, 2-day-old newborns and 3-month-old infants viewed two videos: in one video a moving hand touched a static face, in the other the moving hand stopped before touching it. Results showed that only 3-month-olds, but not newborns, differentiated the touching from the no-touching gesture, displaying a preference for the former over the latter. To test whether newborns could manifest a preferential visual response when the touched body part is different from the face, in Experiment 2 newborns were presented with touching/no-touching gestures in which a hand or an inanimate object -i.e., a spoon- moved towards a static hand. Newborns were able to discriminate a handto-hand touching gesture, but they did not manifest any preference for the object-to-hand touch. The present findings speak in favour of an early ability to visually recognize touching gestures involving the interaction between human body parts.

Peripersonal space is the region closely surrounding our bodies. Within its boundaries, avoidance of threatening objects is crucial for surviving. Here we explored autonomic responses to painful stimuli with respect to the dynamic properties of the peripersonal space in healthy individuals. To this aim, in a series of experiments, we measured the Skin Conductance Response (SCR) to a noxious stimulus approaching and touching the hand, or stopping at different distances (far, near) from it. Results showed that the anticipatory response to an incoming threat is reduced if the stimulus targets a spatial position far away from the body, as compared to a near or bodily location. However, responses to far stimuli change if the boundaries of reachable space are extended further away by active tool use. Noteworthy, SCR is not influenced by a training consisting of a spatial attention task, without active tool use. This evidence sheds novel light on the adaptive role of peripersonal space, showing its importance for the coding of incoming threatening stimuli and its plasticity induced by contingent experience, such as tool use.

The development of human body perception has long been investigated, but little is known about its early origins. This study focused on how a body part highly relevant to the human species, namely the hand, is perceived a few days after birth. Using a preferential-looking paradigm, 24- to 48-hr-old newborns watched biomechanically possible and impossible dynamic hand gestures (Experiment 1, N = 15) and static hand postures (Experiment 2, N = 15). In Experiment 1, newborns looked longer at the impossible, compared to the possible, hand movement, whereas in Experiment 2 no visual preference emerged. These findings suggest that early in life the representation of the human body may be shaped by sensory-motor experience.

Touch is the primary way of learning about the surrounding word from prenatal life throughout infancy (Field, 2001). Inside the womb fetuses frequently touch their body and evidence has shown that these gestures are coordinated and well organized (e.g., Reissland et al., 2013). Given the importance of touch during development, in this study we explored the origins of the ability to visually recognize touching gestures involving others. Looking times and orienting responses were measured within a preference looking task. In Experiment 1 2-day-old neonates and 3-month-old infants were presented simultaneously with two videos of a moving hand approaching a static face: in one video the hand touched the face (touching gesture), in the other the hand stopped before touching occurred (no-touching gesture). Differently, in Experiment 2 2-day-old neonates saw the same two videos but the static face was replaced by another hand while in Experiment 3 neonates saw a moving spoon, instead of a hand, approaching a static hand. In Experiment 1 only 3-month-olds, but not newborns, could differentiate between the two stimuli, as shown by longer looking times and more frequent orientations towards the touching vs no-touching gesture. Conversely, newborns preferred to look towards the no-touching gesture when a static hand instead of a static face was displayed (Experiment 2) and this preference vanished when they see a no-social touch (Experiment 3). These results demonstrate that somatosensory-motor associations accumulated in the womb are sufficient to allow newborns to link executed with observed touching gestures

La NIBS ha una lunga storia nel campo delle neuroscienze cognitive. I primi studi di stimolazione transcranica con correnti elettriche dirette (tES) nell’uomo risalgono all’inizio dell’Ottocento, quelli di stimolazione magnetica (TMS), inizialmente nell’animale, agli ultimi anni di quel secolo. Dagli anni ’90 del secolo scorso questi metodi di stimolazione cerebrale sono stati utilizzati con frequenza sempre crescente. Oggi è disponibile una larga messe di dati empirici, che consente di valutarne appieno l’impatto sulle conoscenze circa l’organizzazione anatomofunzionale del cervello umano.

La NIBS, nell’ultimo quindicennio, è stata utilizzata per cercare di migliorare alcuni tra i più frequenti deficit neuropsicologici: soprattutto l’afasia e la negligenza spaziale unilaterale, per le quali sono disponibili il maggior numero di studi, i deficit di campo visivo (emianopsia) e le aprassie, ove, soprattutto per queste ultime, le evidenze sono assai limitate. I risultati, nel loro complesso, indicano che la NIBS ha effetti positivi su questi deficit. La maggioranza degli studi ha indagato effetti di breve periodo, nell’arco di ore, mentre meno numerose, e sicuramente da incentivare, sono le ricerche che hanno esplorato effetti di più lungo periodo, anche in associazione con trattamenti riabilitativi comportamentali di provata efficacia.

Human movements conform to specific kinematic laws of motion. One of such laws, the "two-thirds power law", describes the systematic co-variation between curvature and velocity of body movements. Noticeably, the same law also influences the perception of moving stimuli: the velocity of a dot moving along a curvilinear trajectory is perceived as uniform when the dot kinematics complies with the two-thirds power law. Instead, if the dot moves at constant speed, its velocity is perceived as highly non-uniform. This dynamic visual illusion points to a strong coupling between action and perception; however, how this coupling is implemented in the brain remains elusive. In this study, we tested whether the premotor cortex (PM) and the primary visual cortex (V1) play a role in the illusion by means of transcranial Direct Current Stimulation (tDCS). All participants underwent three tDCS sessions during which they received active or sham cathodal tDCS (1.5. mA) over PM or V1 of the left hemisphere. During tDCS, participants were required to adjust the velocity of a dot moving along an elliptical trajectory until it looked uniform across the whole trajectory. Results show that occipital tDCS decreases the illusion variability both within and across participants, as compared to sham tDCS. This means that V1 stimulation increases individual sensitivity to the illusory motion and also increases coherence across different observers. Conversely, the illusion seems resistant to tDCS in terms of its magnitude, with cathodal stimulation of V1 or PM not affecting the amount of the illusory effect. Our results provide evidence for strong visuo-motor coupling in visual perception: the velocity of a dot moving along an elliptical trajectory is perceived as uniform only when its kinematics closely complies to the same law of motion that constrains human movement production. Occipital stimulation by cathodal tDCS can stabilize such illusory percept.

Ward and Banissy offer a critical discussion of Mirror-Touch Synesthesia (MTS), with reference to Threshold and Self-Other theories. The authors argue that developmental MTS is linked to differences in the functioning of a mirror system for touch (and pain), which are driven by neurocognitive alterations that lie outside of the somatosensory system and concern bodily awareness and/or the control of self-other representations. This commentary briefly presents some neuropsychological evidence in line with Ward and Banissy’s argument, questioning the potential similarities between MTS and some post-stroke disorders of body representation.

Watching self-generated unilateral hand movements reflected in a mirror–oriented along the midsagittal plane–enhances the excitability of the primary motor cortex (M1) ipsilateral to the moving hand of the observer. Mechanisms detecting sensory–motor conflicts generated by the mirror reflection of such movements might mediate this effect; if so, cortical excitability should be modulated by the magnitude of sensory–motor conflict. To this end, we explored the modulatory effects of an altered visual feedback on M1 excitability in a mirror-box-like paradigm, by increasing or decreasing the speed of the observed movement. Healthy subjects performed movements with their left index finger while watching a video of a hand superimposed to their right static hand, which was hidden from view. The hand observed in the video executed the same movement as the observer’s left hand, but at slower, same, or faster paces. Motor evoked potentials (MEPs) induced by transcranial magnetic stimulation were measured from the first dorsal interosseous and the abductor digiti minimi of the participant’s hidden resting hand. The excitability of the M1 ipsilateral to the moving hand was systematically modulated by the speed of the observed hand movement: the slower the observed movement, the greater the MEP amplitude from both muscles. This evidence shows that the magnitude of the visual–motor conflicts can be used to adjust the activity of the observer’s motor system. Hence, an appropriate alteration of the visual feedback, here the reduction in the movement speed, may be useful to increase its modulatory effect on motor cortical excitability.

Adaptation to optical prisms displacing the visual scene laterally is a widely investigated instance of visuo-motor plasticity, also because prism adaptation (PA) has been extensively used as a treatment for right-brain-damaged patients suffering from left spatial neglect. The lateral visual displacement brought about by prisms, as indexed by a pointing error in the direction of the displacement, is progressively corrected through repeated pointings: after prism removal, a shift in the direction opposite to the prism-induced deviation occurs in visual, proprioceptive, and visuo-proprioceptive straight-ahead tasks (aftereffects, AEs). The cerebellum and the posterior parietal cortex (PPC) are key components of the bilateral cerebral network subserving the AEs, and the reduction of the pointing error during prism exposure in PA. We report the experimental study of a patient with bilateral occipital and left cerebellar damage, who showed a preserved reduction of the pointing errors to rightward displacing prisms, but not the leftward AEs in the proprioceptive straight-ahead task; instead, visual-proprioceptive and visual AEs were preserved. Anodal transcranial Direct Current Stimulation (tDCS) over the left PPC restored the leftward proprioceptive AEs, and anodal tDCS over the left cerebellum abolished the rightward deviation. Conversely, stimulation over the right PPC or the right cerebellum was ineffective. These results provide novel evidence for neuromodulatory effects of tDCS on defective AEs, through the stimulation over dedicated cortical regions.

The study explored the analgesic effects of transcranial direct current stimulation (tDCS) over the motor cortex on postamputation phantom limb pain (PLP). Eight subjects with unilateral lower or upper limb amputation and chronic PLP were enrolled in a crossover, double-blind, sham-controlled treatment program. For 5 consecutive days, anodal (active or sham) tDCS was applied over the motor cortex for 15 minutes at an intensity of 1.5 mA. The 5-day treatment with active, but not sham, tDCS induced a sustained decrease in background PLP and in the frequency of PLP paroxysms, which lasted for 1 week after the end of treatment. Moreover, on each day of active tDCS, patients reported an immediate PLP relief, along with an increased ability to move their phantom limb. Patients' immediate responses to sham tDCS, on the contrary, were variable, marked by an increase or decrease of PLP levels from baseline. These results show that a 5-day treatment of motor cortex stimulation with tDCS can induce stable relief from PLP in amputees. Neuromodulation targeting the motor cortex appears to be a promising option for the management of this debilitating neuropathic pain condition, which is often refractory to classic pharmacologic and surgical treatments. Perspective The study describes sustained and immediate effects of motor cortex stimulation by tDCS on postamputation PLP, whose analgesic action seems linked to the motor reactivation of the phantom limb. These results are helpful for the exploitation of tDCS as a therapeutic tool for the management of neuropathic pain.

Sound-induced flash illusions depend on visual cortical excitability. In this study, we explored whether sound-induced flash illusions are perceived differently in migraine, a condition associated with pathologic cortical hyperexcitability. Methods: Sound-induced flash illusions were examined in 59 migraine patients (mean age 32 ± 16 years; 36 females), 32 without aura and 27 with aura, and in 24 healthy controls (mean age 42 ± 17 years; 16 females). Patients were studied during attacks and interictally. Visual stimuli (flashes) accompanied by sounds (beeps) were presented in different combinations: a single flash with multiple beeps was given to induce the perception of multiple flashes ("fission" illusion), and multiple flashes with a single beep were used to reduce the number of perceived flashes ("fusion" illusion). Results: For migraineurs, the fission illusion was reduced, especially during the attack, and almost abolished when a single flash was combined with 2 beeps (except for those without aura tested interictally); the fusion illusion was less consistently reported in both migraine groups, but not completely disrupted. Conclusions: Results from this study add novel clues to our understanding of visual cortex hyperexcitability in migraine, especially migraine with aura. Furthermore, these analyses underscore how pathologic changes in cortical excitability affect multisensory interactions. Cross-modal illusions represent a valid tool for exploration of functional connectivity between sensory areas, which likely has an important role in the pathophysiology of migraine.

Limb apraxia, a deficit of planning voluntary gestures, is most frequently caused by damage to the left hemisphere, where, according to an influential neurofunctional model, gestures are planned, before being executed through the motor cortex of the hemisphere contralateral to the acting hand. We used anodal transcranial direct current stimulation delivered to the left posterior parietal cortex (PPC), the right motor cortex (M1), and a sham stimulation condition, to modulate the ability of six left-brain-damaged patients with ideomotor apraxia, and six healthy control subjects, to imitate hand gestures, and to perform skilled hand movements using the left hand. Transcranial direct current stimulation delivered to the left PPC reduced the time required to perform skilled movements, and planning, but not execution, times in imitating gestures, in both patients and controls. In patients, the amount of decrease of planning times brought about by left PPC transcranial direct current stimulation was influenced by the size of the parietal lobe damage, with a larger parietal damage being associated with a smaller improvement. Of interest from a clinical perspective, left PPC stimulation also ameliorated accuracy in imitating hand gestures in patients. Instead, transcranial direct current stimulation to the right M1 diminished execution, but not planning, times in both patients and healthy controls. In conclusion, by using a transcranial stimulation approach, we temporarily improved ideomotor apraxia in the left hand of left-brain-damaged patients, showing a role of the left PPC in planning gestures. This evidence opens up novel perspectives for the use of transcranial direct current stimulation in the rehabilitation of limb apraxia.

The field of transcranial electrical stimulation (tES) has experienced significant growth in the past 15 years. One of the tES techniques leading this increased interest is transcranial direct current stimulation (tDCS). Significant research efforts have been devoted to determining the clinical potential of tDCS in humans. Despite the promising results obtained with tDCS in basic and clinical neuroscience, further progress has been impeded by a lack of clarity on international regulatory pathways. Therefore, a group of research and clinician experts on tDCS were convened to review the research and clinical use of tDCS. This report reviews the regulatory status of tDCS and summarizes the results according to research, off-label, and compassionate use of tDCS in the following countries: Australia, Brazil, France, Germany, India, Iran, Italy, Portugal, South Korea, Taiwan, and the US. Research use, off label treatment, and compassionate use of tDCS are employed in most of the countries reviewed in this study. It is critical that a global or local effort is organized to pursue definite evidence to either approve and regulate or restrict the use of tDCS in clinical practice on the basis of adequate randomized controlled treatment trials.

Le neuroscienze si avvalgono oggi di tecniche e metodologie di ricerca sempre più avanzate e con livelli di invasività sempre minori. Questo volume esamina i principali strumenti di stimolazione cerebrale non invasiva (stimolazione transcranica magnetica e elettrica: TMS, tES), descrivendone non solo funzionamento e uso nel diversi ambiti, clinico e di ricerca, ma soffermandosi anche sulle implicazioni etiche.

Action observation typically induces an online inner simulation of the observed movements. Here we investigate whether action observation merely activates, in the observer, the muscles involved in the observed movement or also muscles that are typically used to achieve the observed action goal. In a first experiment, hand and foot motor areas were stimulated by means of transcranial magnetic stimulation, while participants viewed a typical hand action (grasping) or a nonspecific action (stepping over an object) performed by either a hand or a foot. Hand motor evoked potentials (MEPs) increased for grasping and stepping over actions performed by the hand and for grasping actions performed by the foot. Conversely, foot MEPs increased only for actions performed by the foot. In a second experiment, participants viewed a typical hand action (grasping a pencil) and a typical foot action (pressing a foot-pedal) performed by either a hand or a foot. Again, hand MEPs increased not only during the observation of both actions performed by the hand but also for grasping actions performed by the foot. Foot MEPs increased not only during the observation of grasping and pressing actions performed by the foot but also for pressing actions performed by the hand. This evidence indicates that motor activations by action observation occur also in the muscles typically used to perform the observed action, even when the action is executed by an unusual effector, hence suggesting a double coding of observed actions: a strict somatotopic coding and an action goal coding based on the observer's motor expertise. © 2013 Wiley Periodicals, Inc.

Right-brain-damaged patients with unilateral spatial neglect are usually unaware (anosognosic) about their spatial deficits. However, in the scientific literature there is a lack of systematic and quantitative evaluation of this kind of unawareness, despite the negative impact of anosognosia on rehabilitation programs. This study investigated anosognosia for neglect-related impairments at different clinical tasks, by means of a quantitative assessment. Patients were tested in two different conditions (before and after execution of each task), in order to evaluate changes in the level of awareness of neglect-related behaviours triggered by task execution. Twenty-nine right-brain-damaged patients (17 with left spatial neglect) and 27 neurologically unimpaired controls entered the study. Anosognosia for spatial deficits is not pervasive, with different tasks evoking different degrees of awareness about neglect symptoms. Indeed, patients showed a largely preserved awareness about their performance in complex visuo-motor spatial and reading tasks; conversely, they were impaired in evaluating their spatial difficulties in line bisection and drawing from memory, showing over-estimation of their performance. The selectivity of the patients' unawareness of specific manifestations of spatial neglect is further supported by their preserved awareness of performance at a linguistic task, and by the absence of anosognosia for hemiplegia. This evidence indicates that discrete processes are involved in the aware monitoring of cognitive and motor performance, which can be selectively compromised by brain damage. Awareness of spatial difficulties is supported by a number of distinct components, and influenced by the specific skills required to perform a given task.

In the so-called McGurk illusion, when the synchronized presentation of the visual stimulus /ga/ is paired with the auditory stimulus /ba/, people in general hear it as /da/. Multisensory integration processing underlying this illusion seems to occur within the Superior Temporal Sulcus (STS). Herein, we present evidence demonstrating that bilateral cathodal transcranial direct current stimulation (tDCS) of this area can decrease the McGurk illusion-type responses. Additionally, we show that the manipulation of this audio-visual integrated output occurs irrespective of the number of eye-fixations on the mouth of the speaker. Bilateral anodal tDCS of the Parietal Cortex also modulates the illusion, but in the opposite manner, inducing more illusion-type responses. This is the first demonstration of using non-invasive brain stimulation to modulate multisensory speech perception in an illusory context (i.e., both increasing and decreasing illusion-type responses to a verbal audio-visual integration task). These findings provide clear evidence that both the superior temporal and parietal areas contribute to multisensory integration processing related to speech perception. Specifically, STS seems fundamental for the temporal synchronization and integration of auditory and visual inputs. For its part, posterior parietal cortex (PPC) may adjust the arrival of incoming audio and visual information to STS thereby enhancing their interaction in this latter area. © 2014Marques, Lapenta, Merabet, Bolognini and Boggio.