Elisa Castaldi

Elisa Castaldi
University of Florence | UNIFI · Department of Neuroscience, Psychology, Pharmacology and Child health

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44
Publications
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494
Citations

Publications

Publications (44)
Article
Full-text available
To estimate the number of objects in an image, each element needs to be segregated as a single unit. Several principles guide the process of element identification, one of the strongest being symmetry. In the current study, we investigated how symmetry affects the ability to rapidly estimate the number of objects (numerosity). Participants judged t...
Article
Full-text available
Many individuals, when faced with mathematical tasks or situations requiring arithmetic skills, experience exaggerated levels of anxiety. Mathematical anxiety (MA), in addition to causing discomfort, can lead to avoidance behaviors and then to underachievement. However, the factors inducing MA and how MA deploys its detrimental effects are still la...
Article
Developmental dyscalculia (DD) is a specific learning disability affecting the development of numerical and arithmetical skills. The origin of DD is typically attributed to the suboptimal functioning of key regions within the dorsal visual stream (parietal cortex) which support numerical cognition. While DD individuals are often impaired in visual...
Article
To understand the number sense, we need to understand its function. We argue that numerosity estimation is fundamental not only for perception, but also preparation and control of action. We outline experiments that link numerosity estimation with action, pointing to a generalized numerosity system that serves both perception and action preparation...
Article
Full-text available
Numerical estimation of arrays of objects is faster and more accurate when items can be clustered into groups, a phenomenon termed “groupitizing.” Grouping can facilitate segregation into subitizable “chunks,” each easily estimated, then summed. The current study investigates whether spatial grouping of arrays drives specific neural responses durin...
Article
Full-text available
Humans can quickly approximate how many objects are in a visual image, but no clear consensus has been achieved on the cognitive resources underlying this ability. Previous work has lent support to the notion that mechanisms which explicitly represent the locations of multiple objects in the visual scene within a mental map are critical for both vi...
Article
Full-text available
Although luminance is the main determinant of pupil size, the amplitude of the pupillary light response is also modulated by stimulus appearance and attention. Here we ask whether perceived numerosity modulates the pupillary light response. Participants passively observed arrays of black or white dots of matched physical luminance but different phy...
Article
Full-text available
While most animals have a sense of number, only humans have developed symbolic systems to describe and organize mathematical knowledge. Some studies suggest that human arithmetical knowledge may be rooted in an ancient mechanism dedicated to perceiving numerosity, but it is not known if formal geometry also relies on basic, non-symbolic mechanisms....
Article
Full-text available
Groupitizing is a recently described phenomenon of numerosity perception where clustering items of a set into smaller “subitizable” groups improves discrimination. Groupitizing is thought to be rooted on the subitizing system, with which it shares several properties: both phenomena accelerate counting and decrease estimation thresholds irrespective...
Article
Full-text available
The representation of space, time and number is believed to rely on a common encoding system developed to support action guidance. While the ecological advantage of such a shared system is evident when objects are located within the region of space we can act on (known as peri-personal space), it is less obvious in the case of objects located beyon...
Article
Full-text available
Incoming sensory input provides information for the planning and execution of actions, which yield motor outcomes that are themselves sensory inputs. One dimension where action and perception strongly interact is numerosity perception. Many non-human animals can estimate approximately the number of external elements as well as their own actions, an...
Article
Full-text available
Fast saccades are rapid automatic oculomotor responses to salient and ecologically important visual stimuli such as animals and faces. Discriminating the number of friends, foe, or prey may also have an evolutionary advantage. In this study, participants were asked to saccade rapidly towards the more numerous of two arrays. Participants could discr...
Article
Full-text available
When asked to estimate the number of items in a visual array, educated adults and children are more precise and rapid if the items are clustered into small subgroups rather than randomly distributed. This phenomenon, termed "groupitizing", is thought to rely on the recruitment of the subitizing system (dedicated to the perception of very small numb...
Article
Full-text available
Previous work has shown that when arrays of objects are grouped within clusters, participants can enumerate their numerosity more rapidly than when objects are randomly scattered, a phenomenon termed “groupitizing”. Importantly, the magnitude of the grouping advantage correlates with math abilities in children. Here we show that sensory precision o...
Article
Full-text available
Visual crowding refers to the inability to identify objects when surrounded by other similar items. Crowding-like mechanisms are thought to play a key role in numerical perception by determining the sensory mechanisms through which ensembles are perceived. Enhanced visual crowding might hence prevent the normal development of a system involved in s...
Article
Full-text available
Human functional imaging has identified the middle part of the intraparietal sulcus (IPS) as an important brain substrate for different types of numerical tasks. This area is often equated with the macaque ventral intraparietal area (VIP) where neuronal selectivity for non-symbolic numerical stimuli (sets of items) is found. However, the low spatia...
Preprint
Full-text available
Visual crowding refers to the inability to identify objects when surrounded by other similar items. Crowding-like mechanisms are thought to play a key role in numerical perception by determining the sensory mechanisms through which ensembles are perceived. Enhanced visual crowding might hence prevent the normal development of a system involved in s...
Article
Full-text available
Between 1-5:100 people worldwide have never experienced normotypic vision due to a condition called amblyopia, and about 1:4000 suffer from inherited retinal dystrophies that progressively lead to blindness. While a wide range of technologies and therapies are being developed to restore vision, a fundamental question still remains unanswered: would...
Article
Developmental dyscalculia (DD) is a developmental learning disability that manifests as a persistent difficulty in comprehending even the most basic numeric and arithmetic concepts, despite normal intelligence and schooling opportunities. Given the predominant use of numbers in modern society, this condition can pose major challenges in the suffere...
Article
Full-text available
Purpose: We evaluated the potential of magnetic resonance imaging in identifying signs of cortical visual processing with greater sensitivity than standard ophthalmological measures in patients with retinitis pigmentosa (RP) at advanced stages. Methods: Eight patients affected with RP with only bare light perception and weak or absent visual evo...
Article
Full-text available
Humans and other animals base important decisions on estimates of number, and intraparietal cortex is thought to provide a crucial substrate of this ability. However, it remains debated whether an independent neuronal processing mechanism underlies this 'number sense' or whether number is instead judged indirectly on the basis of other quantitative...
Preprint
Full-text available
Between 1 to 5 out of 100 people worldwide has never experienced normotypic vision due to a condition called amblyopia, and about 1 out of 4000 suffer from inherited retinal dystrophies that progressively lead them to blindness. While a wide range of technologies and therapies are being developed to restore vision, a fundamental question still rema...
Preprint
Full-text available
Human functional imaging has identified the middle part of the intraparietal sulcus (IPS) as an important brain substrate for different types of numerical tasks. This area is often equated with the macaque ventral intraparietal area (VIP) where neuronal selectivity for non-symbolic numbers is found. However, the low spatial resolution and whole-bra...
Preprint
Full-text available
Humans and other animals base important decisions on estimates of number, and intraparietal cortex is thought to provide a crucial substrate of this ability. However, it remains debated whether an independent neuronal processing mechanism underlies this 'number sense', or whether number is instead judged indirectly on the basis of other quantitativ...
Article
Full-text available
Dyscalculia, a specific learning disability that impacts arithmetical skills, has previously been associated to a deficit in the precision of the system that estimates the approximate number of objects in visual scenes (the so called ‘number sense’ system). However, because in tasks involving numerosity comparisons dyscalculics’ judgements appears...
Data
Correlation analysis–signed bias and JND. Correlation between the signed PSE number bias and the overall precision during and numerosity judgments. Gray and black circles represents participants of the control and dyscalculic group, respectively. (TIF)
Data
Full raw dataset of all participants. Dataset Neuropsychological Assessment.xls contains demographic data and scores obtained in the tests proposed during the neuropsychological assessment; Dataset Pilot Exp Raw Data.xls contains the full raw dataset of all participants from the pilot experiment. Dataset Main Exp Raw Data.xls contains the full raw...
Preprint
Full-text available
Dyscalculia, a specific learning disability that impacts arithmetical skills, has previously been associated to a deficit in the precision of the system that estimates the approximate number of objects in visual scenes (the so called ‘number sense’ system). However, because in tasks involving numerosity comparisons dyscalculics’ judgements appears...
Article
Full-text available
Periventricular leukomalacia (PVL) is characterized by focal necrosis at the level of the periventricular white matter, often observed in preterm infants. PVL is frequently associated with motor impairment and with visual deficits affecting primary stages of visual processes as well as higher visual cognitive abilities. Here we describe six PVL sub...
Article
Full-text available
Humans and other animals are able to make rough estimations of quantities using what has been termed the approximate number system (ANS). Much evidence suggests that sensitivity to numerosity correlates with symbolic math capacity, leading to the suggestion that the ANS may serve as a start-up tool to develop symbolic math. Many experiments have de...
Article
Leibovich et al. opened up an important discussion on the nature and origins of numerosity perception. The authors rightly point out that non-numerical features of stimuli influence this ability. Despite these biases, there is evidence that from birth, humans perceive and represent numerosities, and not just non-numerical quantitative features such...
Article
Full-text available
Author Summary The majority of pathologies leading to blindness are related to diseases of the photoreceptors, such as retinitis pigmentosa (RP). A wide variety of different methods are being developed in the attempt to partially restore vision in blind people, including a retinal prosthesis that uses electrical stimulation of the retina to elicit...
Data
Visual sensitivity during follow-up. (A) Sensitivity for motion direction discrimination and (B) two interval force choice detection of the individual subjects for the unoperated (closed symbols) and operated eye (open symbols, Argus II system off) as a function of the time after surgery. All patients show equal deficit and no improvement. (TIF)
Data
Control for artifacts. Beta values from anatomically defined ROIs covering the left and right lateral geniculate nuclei (A and B) and calcarine sulcus (C and D) when scanning S4 with 13 (white bars) or with 30 (hatched bars) slices. Beta values do not significantly differ with different number of slices (keeping the same TR) nor in the LGN or in V1...
Data
Supporting TREND Statement Checklist. Transparent reporting of evaluations with nonrandomized design. (PDF)
Data
Dataset with original data for Fig 2 and Fig 4 in the manuscript and for all the supplementary figures (S1 Fig, S2 Fig, S3 Fig and S4 Fig). (XLSX)
Data
The Square Localization task with the Argus II system on. The error (in centimeters) of the pointing of the center of a white square of 7.3 cm on a black screen as a function of the time from the surgery for the individual subjects. The data at zero have been acquired before the operation. Patient S7 did not comply with the training program. All ot...
Data
Control for artifacts. Beta values from anatomically defined ROIs covering the left and right lateral geniculate nuclei (A and B) and calcarine sulcus (C and D) when scanning S6 using an optic fiber bundle and axial slices (white bars) or MRI-compatible goggles and oblique slices (hatched bars). Beta values do not significantly differ depending on...
Article
Full-text available
Psychophysical studies have shown that numerosity is a sensory attribute susceptible to adaptation. Neuroimaging studies have reported that, at least for relatively low numbers, numerosity can be accurately discriminated in the intra-parietal sulcus. Here we developed a novel rapid adaptation paradigm where adapting and test stimuli are separated b...
Article
Full-text available
The recent advance in retinal prosthesis technologies generates hope for partially restoring vision to blind people with retinal pathologies. However, these strategies require the visual system downstream of the retinal circuitry to be capable of transmitting and elaborating visual signals. We studied plastic remodeling in late blind subjects impla...
Article
Full-text available
Considerable recent work suggests that mathematical abilities in children correlate with the ability to estimate numerosity. Does math correlate only with numerosity estimation, or also with other similar tasks? We measured discrimination thresholds of school-age (6- to 12.5-years-old) children in 3 tasks: numerosity of patterns of relatively spars...

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