0000000000281450
AUTHOR
Giuseppe Vallar
showing 8 related works from this author
Understanding metaphors and idioms: A single-case neuropsychological study in a person with Down syndrome
2001
The ability of subject F.F., diagnosed with Down syndrome, to appreciate nonliteral (interpreting metaphors and idioms) and literal (vocabulary knowledge, including highly specific and unusual items) aspects of language was investigated. F.F. was impaired in understanding both metaphors and idioms, while her phonological, syntactic and lexical–semantic skills were largely preserved. By contrast, some aspects of F.F.'s executive functions and many visuospatial abilities were defective. The suggestion is made that the interpretation of metaphors and idioms is largely independent of that of literal language, preserved in F.F., and that some executive aspects of working memory and visuospatial …
Parietal versus temporal lobe components in spatial cognition: Setting the mid-point of a horizontal line
2009
Recent anatomo-clinical correlation studies have extended to the superior temporal gyrus, the right hemisphere lesion sites associated with the left unilateral spatial neglect, in addition to the traditional posterior-inferior-parietal localization of the responsible lesion (supramarginal gyrus, at the temporo-parietal junction). The study aimed at teasing apart, by means of repetitive transcranial magnetic stimulation (rTMS), the contribution of the inferior parietal lobule (angular gyrus versus supramarginal gyrus) and of the superior temporal gyrus of the right hemisphere, in making judgments about the mid-point of a horizontal line, a widely used task for detecting and investigating spa…
Anatomical correlates of visual and tactile extinction in humans: a clinical CT scan study.
1994
The anatomical correlates of tactile and visual extinction with double simultaneous stimulation were investigated in a series of 159 patients with right brain damage caused by stroke. Forty six patients showed extinction (22 tactile, 14 visual, 10 tactile and visual). Over 50% of the patients with extinction had deep lesions, which were found in about 25% of the patients with visuospatial neglect not associated with extinction. In the patients with extinction and cortico-subcortical damage the paraventricular occipital white matter and the dorsolateral frontal cortex were most often involved. By contrast, when neglect was also present, the lesions clustered in the inferior parietal lobule. …
Visual cortex hyperexcitability in migraine in response to sound-induced flash illusions
2015
Objective: 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 mult…
O069. Menstrual cycle affects cortical excitability differently in females with migraine and in healthy controls: a new perspective by cross modal so…
2015
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 cortex hyperexcitability. Aim of the present study was to evaluate SIFI perceptions in healthy women and patients with menstrual migraine and to describe the effects of cyclical change of steroid hormones and cortical responsiveness.
O046. Color vision and visual cortex excitability are impaired in episodic migraine. Simply coexisting or pathophysiologically related dysfunctions?
2015
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 authors reported a selective deficit of shortwavelength cones (S-cones) [1]. Sound-induced flash illusions (SIFI) are a simple way to describe visual distorsion induced by acoustic perception. SIFI critically depend on excitability of primary visual cortex (V1) as they are reduced by facilitatory anodal transcranial direct current stimulation (tDCS)…
Multisensorial Perception in Chronic Migraine and the Role of Medication Overuse.
2020
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, leading to the perception of a single flash. Such illusory perceptions are associated to crossmodal changes in visual cortical excitability. Indeed, increasing occipital cortical excitability, by means of transcranial electrical currents, disrupts the SIFI (ie, fission illusion). Similarly, a reduced fission illusion was shown in patients with episod…
Multisensory integration in hemianopia and unilateral spatial neglect: Evidence from the sound induced flash illusion.
2016
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- …