Giuseppe Vallar

Giuseppe Vallar
Università degli Studi di Milano-Bicocca | UNIMIB · Department of Psychology

MD

About

331
Publications
71,249
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21,026
Citations
Additional affiliations
November 1999 - present
Università degli Studi di Milano-Bicocca
Position
  • Professor
November 1999 - present
Università degli Studi di Milano-Bicocca
Position
  • Professor

Publications

Publications (331)
Article
Full-text available
Visuo-motor adaptation to optical prisms (Prism Adaptation, PA), displacing the visual scene laterally, is a behavioral method used for the experimental investigation of visuomotor plasticity, and, in clinical settings, for temporarily ameliorating and rehabilitating unilateral spatial neglect. This study investigated the building up of PA, and the...
Article
Full-text available
Humans are the only species capable of experiencing pleasure from esthetic stimuli, such as art and music. Neuroimaging evidence suggests that the left dorsolateral prefrontal cortex (DLPFC) plays a critical role in esthetic judgments, both in music and in visual art. In the last decade, non-invasive brain stimulation (NIBS) has been increasingly e...
Article
Full-text available
Temporal Binding Window (TBW) represents a reliable index of efficient multisensory integration process, which allows individuals to infer which sensory inputs from different modalities pertain to the same event. TBW alterations have been reported in some neurological and neuropsychiatric disorders and seem to negatively affects cognition and behav...
Article
Both visuo-spatial neglect and visual extinction may occur following right-brain damage. So far, studies on brain-damaged patients have not provided definite evidence about which lesion patterns may lead to the association or dissociation of these deficits. This study was set out to address this issue using Intracranial Electrical Stimulation (IES)...
Article
Full-text available
Motor learning interacts with and shapes experience-dependent cerebral plasticity. In stroke patients with paresis of the upper limb, motor recovery was proposed to reflect a process of re-learning the lost/impaired skill, which interacts with rehabilitation. However, to what extent stroke patients with hemiparesis may retain the ability of learnin...
Article
L'articolo si apre con una definizione di "neuropsicologia" e riassume le fasi iniziali dello sviluppo della neuropsicologia italiana contemporanea, con particolare riferimento all'approccio metodologico e alle prime attività del "Gruppo di Milano", formatosi, nei primi anni '60 del ‘900, attorno al neurologo Ennio DeRenzi, nella Clinica delle Mala...
Article
Giornale italiano di psicologia (ISSN 0390-5349) Fascicolo 3, settembre 2012 Ente di afferenza: Università degli studi di Milano Bicocca (unibicocca) Copyright c by Società editrice il Mulino, Bologna. Tutti i diritti sono riservati. Per altre informazioni si veda https://www.rivisteweb.it Licenza d'uso L'articoloè messo a disposizione dell'utente...
Article
Prism adaptation (PA) is used to investigate visuo-motor plasticity and to rehabilitate the syndrome of Unilateral Spatial Neglect (USN). After PA, participants show aftereffects (AEs), contralateral to the side of the optical displacement in several tasks. This study explored the features of these AEs, specifically the “egocentric” versus “allocen...
Article
Full-text available
The Rivermead assessment of somatosensory performance (RASP) provides a quantitative assessment of somatosensory processing, suitable for brain-damaged patients suffering from stroke. It consists of seven subcomponents: Subtest 1 (sharp/dull discrimination), Subtest 2 (surface pressure touch), Subtest 3 (surface localization), Subtest 4 (sensory ex...
Article
Full-text available
Unilateral spatial neglect is a neuropsychological syndrome commonly observed after stroke and defined by the inability to attend or respond to contralesional stimuli. Typically, symptoms are assessed using clinical tests that rely upon visual/perceptual abilities. However, neglect may affect high-level representations controlling attention in othe...
Chapter
Full-text available
Unilateral spatial neglect is a neuropsychological syndrome, more frequent after damage to the right cerebral hemisphere, featuring an impaired ability to orient toward the contralateral left side of space and the body, and the inability to detect and report events from that side, of which patients are not aware. In addition to these defective mani...
Article
Adaptation to optical prisms (Prismatic Adaptation, PA) displacing the visual scene laterally, on one side of visual space, is both a procedure for investigating visuo-motor plasticity and a powerful tool for the rehabilitation of Unilateral Spatial Neglect (USN). Two processes are involved in PA: i) recalibration (the reduction of the error of man...
Article
Ennio De Renzi (1924-2014), physician and neurologist, is the founder of modern Italian neuropsychology. De Renzi not only made important studies, but also formulated methodological principles, overcoming the insufficiencies of the traditional qualitative clinical method of observing individual patients with apparent deficits: research is to be mad...
Article
Background and purpose Neuromodulation is a promising approach to increase motor recovery in stroke. However, so far, there is a scarcity of evidence documenting the clinical potential of tDCS administered in the acute phase of stroke. The present study aims to examine the clinical effects of a treatment involving the application of tDCS in the acu...
Article
Full-text available
Unilateral spatial neglect (USN) is a neuropsychological syndrome, typically caused by lesions of the right hemisphere, whose features are the defective report of events occurring in the left (contralesional) side of space and the inability to orient and set up actions leftwards. Multisensory integration mechanisms, largely spared in USN patients,...
Article
Since the 1960s, evidence from healthy participants and brain-damaged patients, neuroimaging and non-invasive brain stimulation studies has specified the neurofunctional architecture of the short-term memory (STM) system supporting the temporary retention of a limited amount of verbal material. Auditory-verbal, later termed Phonological (Ph), STM,...
Article
Multisensory processing can be assessed by measuring susceptibility to crossmodal illusions such as the Sound-Induced Flash Illusion (SIFI). When a single flash is accompanied by 2 or more beeps, it is perceived as multiple flashes (fission illusion); conversely, a fusion illusion is experienced when more flashes are matched with a single beep, lea...
Chapter
Reports of clinical observations of impairments of human mental functions that can be traced back to brain damage or dysfunction date to centuries ago. However, the naissance of neuropsychology as a scientific discipline is much more recent, dating to the 19th century. A most relevant observation was Paul Broca's report that damage to a frontal pre...
Article
In brain damage patients with unilateral spatial neglect (USN), the differential diagnosis between the presence and absence of a unilateral visual half-field deficit (VHFD) is hampered by the similarity of their phenomenology. The absence of stimuli detection in the contralateral visual field, indeed, can be due to the co-occurrence of USN and VHFD...
Article
Prism adaptation (PA)is a promising treatment in the rehabilitation of post-stroke cognitive disorders such as unilateral spatial neglect or constructional deficits. Right brain damage can bring about another representational spatial disorder, termed «hyperschematia», and defined by a left-sided disproportionate expansion of drawings by copy and fr...
Article
The knowledge of the size of our own body parts is essential for accurately moving in space and efficiently interact with objects. A distorted perceptual representation of the body size often represents a core diagnostic criterion for some psychopathological conditions. The metric representation of the body was shown to depend on somatosensory affe...
Article
Our motor behavior and interactions with the external world are mediated by many spatial systems. This study investigated the absence of visual control of performance in the manual line bisection task, with the goal of teasing apart the role of the motor component of the visuomotor spatial system. Results show a rightward bias when right-handed ind...
Article
Spatial neglect is a debilitating disorder frequently observed after damage to the right cerebral hemisphere. Previous investigations have revealed that prism adaptation (PA) therapy can lead to improvements in neglect-related symptoms. In the typical PA protocol patients repeatedly point toward a visual target while wearing prism goggles. A few ye...
Article
Full-text available
The right cerebral hemisphere plays a crucial rule in spatial cognition, spanning from perception of elementary features, such as location, color, line orientation or shape to representation of different spaces (3D space, allocentric, egocentric, face, personal, peri-personal, or imaginal). One important aspect of its contribution concerns the perc...
Article
Full-text available
Transcranial direct current stimulation (tDCS) is increasingly used in both research and therapeutic settings, but its precise mechanisms remain largely unknown. At a neuronal level, tDCS modulates cortical excitability by shifting the resting membrane potential in a polarity-dependent way: anodal stimulation increases the spontaneous firing rate,...
Chapter
Full-text available
The development and change of knowledge on the function of the parietal lobe from the second half of the 19th century to the early 1970s are reviewed. Motor and somatosensory functions were initially localized in a broad frontoparietal region. At the beginning of the 20th century the motor cortex was restricted to the posterior frontal lobe. The se...
Chapter
Unilateral spatial neglect is a disabling neurologic deficit, most frequent and severe after right-hemispheric lesions. In most patients neglect involves the left side of space, contralateral to a right-hemispheric lesion. About 50% of stroke patients exhibit neglect in the acute phase. Patients fail to orient, respond to, and report sensory events...
Article
Full-text available
Da qualche anno anche in Italia si sono affacciate sulla scena del diritto e del processo penale le c.d. neuroscienze, vale a dire quel complesso di discipline che indaga sulle connessioni neuronali dei comportamenti umani. A livello teorico, e de iure condendo, la dottrina penalistica si è, quindi, interrogata sulla possibilità di una “rifondazion...
Article
Full-text available
Visuo-motor adaptation to optical prisms displacing the visual scene (prism adaptation, PA) is a method used for investigating visuomotor plasticity in healthy individuals and, in clinical settings, for the rehabilitation of unilateral spatial neglect. In the standard paradigm, the adaptation phase involves repeated pointings to visual targets, whi...
Article
Converging evidence on voluntary actions underlays the existence of a motor monitoring system able to compare the predicted and the actual consequences of our movements. In this context, both the premotor cortex (PMC) and the posterior parietal cortex (PPC) play a role in action monitoring and awareness. The present study explores the role of PMC a...
Article
Full-text available
The stage at which processing of tactile distance occurs is still debated. We addressed this issue by implementing an adaptation-aftereffect paradigm with passive touch. We demonstrated the presence of a strong aftereffect, induced by the simultaneous presentation of pairs of tactile stimuli. After adaptation to two different distances, one on each...
Conference Paper
Full-text available
Introduction Motor execution, planning, and learning are altered by transcranial Direct Current Stimulation (tDCS). The potential of this technique for modulating action monitoring and awareness has not been explored so far. Optimal motor control relies on internal representations of the intended, predicted, and actual action. The brain is equipped...
Article
Introduction In the last decade, transcranial direct current stimulation (tDCS) has been increasingly used in experimental and clinical settings. Nevertheless, its neurophysiological underpinnings still remain unclear. Moreover, under debate is how and to what extent these effect spread through brain pathways. Objectives In this study, we explored...
Article
Right-brain-damaged patients may show a reading disorder termed neglect dyslexia. Patients with left neglect dyslexia omit letters on the left-hand-side (the beginning, when reading left-to-right) part of the letter string, substitute them with other letters, and add letters to the left of the string. The aim of this study was to investigate the pa...
Article
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 brai...
Article
Full-text available
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 h...
Article
This Corrigendum is issued because the Department of Psychology, and the NeuroMi – Milan Center for Neuroscience are part of, and belong to, the same institution, namely the University of Milano-Bicocca, Milan, Italy. They are not two different institutions, as we erroneously stated in the original manuscript: that erroneous statement may affect th...
Article
Full-text available
The bisection of lines positioned radially (with the two ends of the line close and far, with respect to the participant's body) has been less investigated than that of lines placed horizontally (with their two ends left and right, with respect to the body's midsagittal plane). In horizontal bisection, patients with left neglect typically show a ri...
Article
The physiological regulation of skin temperature can be modulated not only by autonomic brain regions, but also by a network of higher-level cortical areas involved in the maintenance of a coherent representation of the body. In this study we assessed in healthy participants if the sensorimotor changes taking place during motor adaptation to the la...
Article
Full-text available
Background and objectives Evidence of abnormal color vision processing in migraine comes from observation of positive symptoms during visual aura, effects of strong color contrast triggering attacks and of colored-spectacles reducing migraine frequency. Although the central or peripheral basis of such color misperception remains unclear, several au...
Article
Full-text available
The sound-induced flash illusions (SIFI) represent a valid tool to explore multimodal perception and are critically dependent on visual and acoustic cortical excitability [1, 2]. In a previous study [3], we observed a significant reduction of illusions in migraine patients with respect to healthy controls, probably due to a condition of visual cort...
Conference Paper
Giuseppe Vallar, MD, specialty in Neurology, Italian, was born in Milan. Department of Psychology, University of Milano-Bicocca, & IRCCS Italian Auxological Institute, Milan, Italy. Email: giuseppe.vallar@unimib.it Giuseppe Vallar since 1999, Professor of Psychobiology and Physiological Psychology and, since 2009, the Director of the Specialty Scho...
Article
Full-text available
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 a...
Article
Full-text available
The study assessed whether the auditory reference provided by a music scale could improve spatial exploration of a standard musical instrument keyboard in right-brain-damaged patients with left spatial neglect. As performing music scales involves the production of predictable successive pitches, the expectation of the subsequent note may facilitate...
Article
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. Sound-induced flash illusions were examined in 59 migraine patients (mean age = 32 ± 16 years; 36 females), 3...
Chapter
'Short-term memory' refers to a number of systems, with limited capacities, which secure the temporary (in the range of seconds) retention of a variety of materials. Short-term memory systems are distinct from the more peripheral and short-lasting components of echoic memory for auditory stimuli, and iconic memory for visual stimuli. The three more...
Article
Full-text available
Since the early 1960s, human neuropsychology, the study of brain-behavior interrelations, mainly based on the analysis of their pathological variations, brought about by brain damage, has had a remarkable systematical development in Italy. All this started in Milan, with the neurologist Ennio de Renzi, and his collaborators (Luigi Vignolo, then Ann...
Article
Full-text available
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...
Article
Touch has an emotional and communicative meaning, and it plays a crucial role in social perception and empathy. The intuitive link between others' somatosensations and our sense of touch becomes ostensible in mirror-touch synesthesia, a condition in which the view of a touch on another person's body elicits conscious tactile sensations on the obser...
Article
This study investigates whether the rubber hand illusion (RHI) can induce a remission of somatoparaphrenia, a somatic delusion usually following righthemisphere damage, which typically manifests as a defective sense of ownership of one's contralesional body parts. First, we show that patients with somatoparaphrenia can experience a reliable RHI, ex...
Article
Despite transcranial direct current stimulation (tDCS) is increasingly used in experimental and clinical settings, its precise mechanisms of action remain largely unknown. At a neuronal level, tDCS modulates the resting membrane potential in a polarity-dependent fashion: anodal stimulation increases cortical excitability in the stimulated region, w...