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    Archived pages: 251 . Archive date: 2013-07.

  • Title: Francesca Tinelli
    Descriptive info: Francesca Tinelli.. Thursday, 27 January 2011 19:06.. PisaVisionLab.. Post-Doc in Cognitive Science, University of Florence.. Contacts.. Email: francesca.. tinelli (AT) inpe.. unipi.. Telephone: +39 050 3153175.. Research laboratories.. CNR Institute of Neuroscience, Pisa.. Department of Psychology, University of Florence.. Stella Maris Foundation, Pisa, Italy.. Current research and interests.. Clinical Psychology.. 2012.. Gori, M.. , Tinelli, F.. , Sandini, G.. , Cioni, G.. & Burr, D.. (2012).. Impaired visual size-discrimination in children with movement disorders,Neuropsychologia, 8 (50), 1838-1843.. Multisensory integration of spatial information occurs late in childhood, at around eight years (Gori, Del Viva, Sandini, & Burr, 2008).. For younger children, the haptic system dominates size discrimination and vision dominates orientation discrimination: the dominance may reflect sensory calibration, and could have direct consequences on children born with specific sensory disabilities.. Here we measure thresholds for visual discrimination of orientation and size in children with movement disorders of upper limbs.. Visual orientation discrimination was very similar to the age-matched typical children, but visual size discrimination thresholds were far worse, in all eight individuals with early-onset movement disorder.. This surprising and counterintuitive result is readily explained by the cross-sensory calibration hypothesis: when the haptic sense is unavailable for manipulation, it cannot be readily used to estimate size, and hence to calibrate the visual experience of size: visual discrimination is subsequently impaired.. This complements a previous study showing that non-sighted children have reduced acuity for haptic orientation, but not haptic size, discriminations (Gori, Sandini, Martinoli, & Burr, 2010).. Together these studies show that when either vision or haptic manipulation is impaired, the impairment also impacts on complementary sensory systems that are calibrated by that one.. Tinelli, T.. , Cicchini, G.. M.. , Arrighi, R.. , Tosetti, M.. , Morrone M.. C.. Blindsight in children with congenital and acquired cerebral lesions, Cortex (published online 10 August 2012).. PDF.. It has been shown that unconscious visual function can survive lesions to optical radiations and/or primary visual cortex (V1), a phenomenon termed “blindsight”.. Studies on animal models (cat and monkey) show that the age when the lesion occurs determines the extent of residual visual capacities.. Much less is known about the functional and underlying neuronal repercussions of early cortical damage in humans.. We measured sensitivity to several visual tasks in four children with congenital unilateral brain lesions that severely affected optic radiations, and in another group of three children with similar lesions, acquired in childhood.. In two of the congenital patients, we measured blood oxygenation level dependent (BOLD) activity in response to stimulation of each visual field quadrants.. Results show clear evidence of residual unconscious processing of position, orientation and motion of visual stimuli displayed in the scotoma of congenitally lesioned children, but not in the children with acquired lesions.. The calcarine cortical BOLD responses were abnormally elicited by stimulation of the ipsilateral visual field and in the scotoma region, demonstrating a profound neuronal reorganization.. In conclusion, our data suggest that congenital lesions can trigger massive reorganization of the visual system to alleviate functional effects of early brain insults.. 2011.. Tinelli, F.. , Guzzetta, A.. , Bertini, C.. , Ricci, D.. , Mercuri, E.. , Ladavas, E.. , et al.. (2011).. Greater Sparing of Visual Search Abilities in Children After Congenital Rather Than Acquired Focal Brain Damage,Neurorehabil Neural Repair,.. BACKGROUND: Visual search refers to the capacity of an individual to find a target among simultaneously presented distracters and is based on visual abilities such as a fast visual processing and an accurate control of ballistic eye movements (saccades) that guide the fovea to the target location.. OBJECTIVE: In adults, visual field defects caused by brain damage are often associated with visual search disorders; in children, little is known about the effects of early brain lesions on visual search abilities.. METHODS: To test the presence of visual search defects and to investigate the role of cortical plasticity after early brain lesions, 29 children with congenital or acquired cerebral lesions, with and without visual field defects, underwent a visual search test battery.. RESULTS: The children with acquired lesions and visual field defects had longer reaction times (RTs) in the contralesional visual field compared with the ipsilesional, whereas those with congenital lesions and visual field defects did not have differences in RTs between the contralateral and ipsilateral visual fields and had a visual search pattern similar to children without a visual field defect.. CONCLUSIONS: These findings support the hypothesis of more effective mechanisms of functional compensation and reorganization of the visual system in children with very early brain lesions, as opposed to those with later damage.. 2010.. Ricci, D.. , Cesarini, L.. , Gallini, F.. , Serrao, F.. , Leone, D.. , Baranello, G.. (2010).. Cortical visual function in preterm infants in the first year,J Pediatr, 4 (156), 550-555.. OBJECTIVE: To assess visual function in low-risk preterm infants at 3, 5, and 12 months corrected age to determine whether the maturation of visual function in the first year is similar to that reported in term-born infants.. STUDY DESIGN: Seventy-five low-risk infants (25.. 0-30.. 9 weeks gestation) underwent ophthalmological examinations and a battery of tests (fix and follow, visual fields, acuity, attention at distance, and fixation shift) designed to assess various aspects of visual function at 3, 5, and 12 months corrected age.. RESULTS: The results were comparable with normative data from term-born infants in all tests but fixation shift, suggesting that maturation of most aspects of visual function is not significantly affected by preterm birth.. In contrast, >25% of preterm infants failed the fixation shift test at 3 months, with a higher percentage of failing at 5 and 12 months.. CONCLUSIONS: There is a specific profile of early visual behavior in low-risk preterm infants, with a high percentage of infants failing a test that specifically assesses visual attention and provides a measure of cortical processing.. Guzzetta, A.. , D'Acunto, G.. , Rose, S.. , Boyd, R.. & Cioni, G.. Plasticity of the visual system after early brain damage,Dev Med Child Neurol, 10 (52), 891-900.. The aim of this review is to discuss the existing evidence supporting different processes of visual brain plasticity after early damage, as opposed to damage that occurs during adulthood.. There is initial evidence that some of the neuroplastic mechanisms adopted by the brain after early damage to the visual system are unavailable at a later stage.. These are, for  ...   for motion perception was also evident in the seminatural situation of a driving simulation video game.. The perceptual deficit for translational motion was reinforced by functional magnetic resonance imaging studies.. Translational motion elicited no response in the MT complex, although it did produce a strong response in many visual areas when contrasted with blank stimuli.. However, radial and rotational motion produced a normal pattern of activation in a subregion of the MT complex.. These data reinforce the existent evidence for independent cortical processing for translational, and circular or radial flow motion, and further suggest that the two systems have different vulnerability and plasticity to prenatal damage.. They also highlight the complexity of visual motion perception, and how the delicate balance of neural activity can lead to paradoxical effects such as consistent misperception of the direction of motion.. We advance a possible explanation of a reduced spatial sampling of the motion stimuli and report a simple model that simulates well the experimental results.. Guzzetta, F.. , Fazzi, E.. , Biagioni, E.. , Veggiotti, P.. Neurodevelopmental evolution of West syndrome: a 2-year prospective study,Eur J Paediatr Neurol, 5 (12), 387-397.. OBJECTIVE: The aim of this study was to evaluate the epileptic and developmental evolution in infants with West syndrome.. METHODS: A prospective study of 21 infants was performed, with a follow-up at 2 years.. Serial assessment included long-term EEG monitoring, visual and auditory evaluation and assessment of neurodevelopment.. RESULTS: Neurosensory and developmental impairments at the spasm onset were transitory in seven cases, including four cryptogenic forms.. In all other cases, there was a progressive worsening in neurosensory and developmental impairments.. The epileptic evolution was generally better: in 11 of the 16 infants without seizures at outcome, spasms had already disappeared by 2 months after disease onset.. Statistic analysis of results showed a correlation between neurosensory impairment and development throughout the whole follow-up.. In addition, visual function at T1 resulted significant predictor of developmental outcome.. Among the epileptic features, disorganization of slow sleep was an unfavorable prognostic factor.. CONCLUSION: Some forms of West syndrome are confirmed to have a benign evolution: among them there are not only cryptogenic cases but also symptomatic ones without significant neurodevelopmental impairment.. Abnormalities of sleep organization, expression of the pervasive epileptic disorder, seem to play a role in determining a developmental deterioration.. Neurosensory impairment since the onset of the disease could be a relevant cause of the developmental disorder.. , Pei, F.. , Mazzotti, S.. , Baldassi, S.. The assessment of visual acuity in children with periventricular damage: a comparison of behavioural and electrophysiological techniques,Vision Res, 10 (48), 1233-1241.. It has been controversial whether electrophysiology offers better precision than behavioural techniques in measuring visual acuity in children with brain damage.. We investigated the concordance between sweep VEPs and Acuity Cards (AC) in 29 children with periventricular leukomalacia (PVL), the most common type of brain damage in preterm infants.. An overall good correlation was shown but with relatively better behavioural acuity values.. VEP/AC ratio was significantly correlated to corpus callosum posterior thinning.. We propose that this result reflects the efficacy of the compensatory mechanisms following early brain damage which may differentially affect the two methods.. 2007.. Caputo, R.. , Campa, L.. , Frosini, R.. (2007).. Motor coordination in children with congenital strabismus: effects of late surgery,Eur J Paediatr Neurol, 5 (11), 285-291.. BACKGROUND: Strabismus is one of the most common visual disorders in infancy.. While there is a great attention on the effects of the timing of surgery as to the development of binocular vision, little is known about the possible influence of congenital strabismus on perceptual-motor and more generally, on neuromotor development.. AIMS: Aim of this study was to investigate perceptual-motor and motor coordination abilities of 19 children with essential congenital esotropia who underwent a late surgery (after 4 years), compared to 23 age-matched controls.. METHODS: Children were tested using the Movement Assessment Battery for Children (Movement ABC) that were performed both 1-week before surgery (T1) and about 3 months (+/-2 weeks) after surgery (T2).. RESULTS AND CONCLUSIONS: At T1, abnormal or borderline results were found in more than half of the children with strabismus, as opposed to only about 17% of the controls.. At T2 none of the children showed abnormal Movement ABC total scores and there was no difference in global scores between the study and the control group.. The two groups also did not show any significant difference in individual items of the movement ABC with the exception of those assessing ball skills.. Our results suggest that surgical correction of strabismus, even when performed after the 4th year of life, appears to be effective in improving perceptual-motor and motor function.. 2006.. Baranello, G.. , Rando, T.. , D'Acunto, M.. G.. , Epifanio, R.. , Frisone, M.. F.. (2006).. Auditory attention at the onset of West syndrome: correlation with EEG patterns and visual function,Brain Dev, 5 (28), 293-299.. At the onset of West syndrome a specific impairment of visual function has been clearly demonstrated, while other aspects of sensorial development, and in particular of the auditory function, have been less studied.. The aim of this study was to evaluate auditory function and orienting responses at the onset of West syndrome, and to relate the results with EEG patterns, visual function and neurodevelopmental competence.. A prospective multicentric study was performed on 25 successively enrolled infants with West syndrome; all the patients underwent a full clinical assessment, including MRI and video-EEG, visual function and auditory orienting responses (AORs) as well as Griffiths' developmental scales.. The whole assessment performed at the onset of spasms (T0) was repeated after two months (T1).. AORs resulted significantly impaired both at T0 and T1.. At the onset of spasms a highly significant relationship of auditory attention with visual function and neurodevelopmental competence was shown in both cryptogenic and symptomatic forms, but it was no longer present after two months.. Our results may suggest a possible pervasive effect of the epileptic disorder on sensory processing, associated to a deficit of neurodevelopment.. Although we failed to show a significant correlation between auditory orienting responses and EEG patterns, some evidence seems to support at least partially an influence of the epileptic disorder per se on the genesis of the sensorial impairment.. A longer follow up and a larger cohort will be useful for a better clarification of these findings..

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  • Title: PisaVisionLab
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  • Title: Kyriaki Mikellidou
    Descriptive info: Kyriaki Mikellidou.. Post-Doc in Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa.. Email: kmikellidou (AT) gmail.. com.. Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa.. Education.. 2009 – 2013.. University of York, United Kingdom.. PhD in Psychology.. 2008 – 2009.. MSc in Cognitive Neuroscience.. 2005 – 2008 University of York, United Kingdom.. BSc (.. Hons.. ) Psychology.. Visual illusions.. Neuroimaging of vision.. 2013.. Thompson, P.. & Mikellidou, K.. Applying the Helmholtz illusion to fashion: horizontal stripes won't make you look fatter,Iperception, 1 (2), 69-76.. A square composed of horizontal lines appears taller and narrower than an identical square made up of vertical lines.. Reporting this illusion, Hermann von Helmholtz noted that such illusions, in which filled space seems to be larger than unfilled space, were common in everyday life, adding the observation that ladies' frocks with horizontal stripes make the figure look taller.. As this assertion runs counter to modern  ...   4.. 5% wider than a square of vertical stripes to match its perceived width.. This illusion holds when the horizontal or vertical lines are on the dress of a line drawing of a woman.. We have examined the claim that these effects apply only for 2-dimensional figures in an experiment with 3-D cylinders and find no support for the notion that horizontal lines would be 'fattening' on clothes.. Significantly, the illusion persists when the horizontal or vertical lines are on pictures of a real half-body mannequin viewed stereoscopically.. All the evidence supports Helmholtz's original assertion.. Conferences.. Mikellidou, K.. Simple line-length estimation not so simple.. Vision Sciences Society Annual Meeting,.. Naples, Florida.. Bisection and dissection of horizontal lines: the long and the short of the Oppel-Kundt illusion.. Journal of Vision, 11,.. 1184.. The vertical-horizontal and the Oppel-Kundt illusions: how our visual perception changes.. Perception, 40,.. 116.. Thompson,P.. (2009) The 3-D Helmholtz square illusion: more reasons to wear horizontal stripes.. Journal of Vision, 9,.. 50..

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  • Title: PisaVisionLab
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  • Title: Giovanni Anobile
    Descriptive info: Giovanni Anobile.. PhD Student in Cognitive Science, University of Florence.. Email: GiovanniAnobile (AT) hotmail.. 2009: Italian Master Degree in Experimental Psychology.. Summa cum laude.. University of Florence.. 2007: Italian Degree in Experimental Psychology.. Numerosity perception.. Multi-sensory perception.. Dyscalculia.. Attention.. Anobile, G.. Linear mapping of numbers onto space requires attention,Cognition, 3 (122), 454-459.. Mapping of number onto space is fundamental to mathematics and measurement.. Previous research suggests that while typical adults with mathematical schooling map numbers veridically onto a linear scale, pre-school children and adults without formal mathematics training, as well as individuals with dyscalculia, show strong compressive, logarithmic-like non-linearities when mapping both symbolic and non-symbolic numbers onto the numberline.. Here we show that the use of the linear scale is dependent on attentional resources.. We asked typical adults to position clouds of dots on a numberline of various lengths.. In agreement with previous research, they did so veridically under normal conditions, but when asked to perform a concurrent attentionally-demanding conjunction task, the mapping followed a compressive, non-linear function.. We model the non-linearity both by the commonly assumed logarithmic transform, and also with a Bayesian model of central tendency.. These results suggest that veridical representation numerosity requires attentional mechanisms.. , Turi, M.. The effects of cross-sensory attentional demand on subitizing and on mapping number onto space,Vision Res,.. Various aspects of numerosity judgments, especially subitizing and the mapping of number onto space, depend strongly on attentional resources.. Here we use a dual-task paradigm to investigate the effects of cross-sensory attentional demands on visual subitizing and spatial mapping.. The results show that subitizing is strongly dependent on attentional resources, far more so than is estimation  ...   in the subitizing range, are adaptable under conditions of high attentional load.. These results support the idea that numerosity is detected by a perceptual mechanism that operates over the entire range of numbers, supplemented by an attention-based system for small numbers (subitizing).. & Anobile, G.. Subitizing but not estimation of numerosity requires attentional resources,J Vis, 6 (10), 20.. The numerosity of small numbers of objects, up to about four, can be rapidly appraised without error, a phenomenon known as subitizing.. Larger numbers can either be counted, accurately but slowly, or estimated, rapidly but with errors.. There has been some debate as to whether subitizing uses the same or different mechanisms than those of higher numerical ranges and whether it requires attentional resources.. We measure subjects' accuracy and precision in making rapid judgments of numerosity for target numbers spanning the subitizing and estimation ranges while manipulating the attentional load, both with a spatial dual task and the "attentional blink" dual-task paradigm.. The results of both attentional manipulations were similar.. In the high-load attentional condition, Weber fractions were similar in the subitizing (2-4) and estimation (5-7) ranges (10-15%).. In the low-load and single-task condition, Weber fractions substantially improved in the subitizing range, becoming nearly error-free, while the estimation range was relatively unaffected.. The results show that the mechanisms operating over the subitizing and estimation ranges are not identical.. We suggest that pre-attentive estimation mechanisms works at all ranges, but in the subitizing range, attentive mechanisms also come into play.. Anobile G, Turi M, Burr D C, 2010, "Subitizing but not estimation of numerosity requires attentional resources".. Perception, 39 ECVP Abstract Supplement, page 80.. Theses..

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  • Title: Graduate Students
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  • Title: PisaVisionLab
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  • Title: Elisa Castaldi
    Descriptive info: Elisa Castaldi.. Email: elisa.. castald (AT) gmail.. Telephone: +39 050 3153172.. Colour Perception.. fMRI.. Castaldi, E.. , Frijia, F.. , Morrone, M.. C.. Selectivity to spatial phase of chromatic cortical mechanisms: an fMRI study [Cavalese retreat CNR Institutes of Neuroscience 2011: Poster].. Selectivity to spatial phase of chromatic cortical mechanisms: an fMRI study.. Honours Thesis, University Vita-Salute San Raffaele Milan (2009)..

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  • Title: PisaVisionLab
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  • Title: Michele Fornaciai
    Descriptive info: Michele Fornaciai.. PhD Student in Neuroscience, University of Florence.. Email: fornaciai (AT) hotmail.. Department of Neuroscience, Psychology, Pharmacology and Child Health.. 2007 - 2010.. Bachelor in General and Experimental Psychology, University of Florence.. 2010 - 2012.. Master degree in Psychology (Experimental Psychology), University of Florence.. 2012 - now.. PhD course in Neuroscience.. Time perception.. Motion perception.. Fornaciai M.. “Percezione visiva del movimento e meccanismi temporali”.. Visual perception of motion and temporal mechanisms.. University of Florence, Faculty of Psychology (2012)..

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  • Title: PisaVisionLab
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