Paolo Bartolomeo

French Institute of Health and Medical Research | Inserm

When we relive our memories, enjoy a novel, create a painting, or predict whether our car will fit in a parking spot, we use our “Mind’s Eye” to engage in Visual Mental Imagery (VMI). The current consensus is that VMI depends crucially on early visual areas. By contrast, longstanding evidence from neurological patients demonstrates that vivid VMI i...

Left-sided spatial neglect is a very common and challenging issue after right-hemispheric stroke, which strongly and negatively affects daily living behavior and recovery of stroke survivors. The mechanisms underlying recovery of spatial neglect remain controversial, particularly regarding the involvement of the intact, contralesional hemisphere, w...

Exogenous attention, the process that makes external salient stimuli pop-out of a visual scene, is essential for survival. How attention-capturing events modulate human brain processing remains unclear. Here we show how the psychological construct of exogenous attention gradually emerges over large-scale gradients in the human cortex, by analyzing...

Current deep neural networks (DNNs) are far from being able to model the rich landscape of human visual experience. Beyond visual recognition, we explore the neural substrates of visual mental imagery and other visual experiences. Rather than shared visual representations, temporal dynamics and functional connectivity of the process are essential....

The famous “Piazza del Duomo” paper, published in Cortex in 1978, inspired a considerable amount of research on visual mental imagery in brain-damaged patients. As a consequence, single-case reports featuring dissociations between perceptual and imagery abilities challenged the prevailing model of visual mental imagery. Here we focus on mental imag...

Stroke-induced aphasia is a leading cause of cognitive disability. The healthy right hemisphere may play a role in aphasia compensation. Music-based therapy, known to enhance cognitive functions after stroke, offers a potential intervention due to its impact on brain connectivity, engaging both hemispheres. In this proof-of-concept study, we aimed...

How do attention and consciousness interact in the human brain? Rival theories of consciousness disagree on the role of fronto-parietal attentional networks in conscious perception. We recorded neural activity from 727 intracerebral contacts in 13 epileptic patients, while they detected near-threshold targets preceded by attentional cues. Clusterin...

Objective: To assess the most sensitive combination of tests to detect peri-personal unilateral neglect (UN) after stroke. Methods: The present study is a secondary analysis of a previously reported multicentric study of 203 individuals with right hemisphere damage (RHD), mainly subacute stroke, 11 weeks post onset on average, and 307 healthy co...

Different individuals experience varying degrees of vividness in their visual mental images. The distribution of these variations across different imagery domains, such as object shape, color, written words, faces, and spatial relationships, remains unknown. To address this issue, we conducted a study with 117 healthy participants who reported diff...

The meta-analysis conducted by Székely et al. described the lack of beneficial effect of prism adaptation in neglect patients. The authors concluded that the results did "not support the routine use of prism adaptation as a therapy for spatial neglect". However, a possible nuance to this conclusion could be that the response (or lack thereof) of ne...

We are grateful to Cornelius Weiller and Michel Rijntjes for raising crucial issues in cognitive neurology,¹ which allowed us to better focus on some conclusions from our study.² We fully agree with Weiller and Rijntjes¹ that brain anatomy should be used as a ‘tool for developing concepts about the functions of the brain’. However, a preliminary st...

Visual Mental Imagery (VMI) allows the generation of an image of an item in its absence, via retrieving, modifying, and recombining sensory information from long-term memory. The literature on this field has been rapidly expanding within five domains of VMI: visuospatial, colors, shapes, letters, and face imagery. Yet, the extent of overlap between...

We used ultra-high field 7T fMRI to establish the neural circuits involved in visual mental imagery and perception, and to elucidate the neural mechanisms associated with imagery absence in congenital aphantasia. Ten typical imagers and 10 aphantasic individuals performed imagery and perceptual tasks in five domains: object shape, object color, wri...

We conducted a study with 117 healthy participants who reported different levels of imagery vividness, to examine how individual variations in the vividness of visual mental imagery affect different imagery domains, such as object shape, color, written words, faces, and spatial relationships. Of these participants, 44 reported experiencing absent o...

Classical theoretical models suggest that visual short-term memory can be divided in two main memory systems: sensory memory, a short-lasting but high-capacity memory storage and working memory, a long-lasting but low-capacity memory store. Whilst, previous research has systematically shown a strong interplay between attentional mechanisms and work...

Introduction The ecological assessment and the analysis of spatial organization behaviors, like the organization of objects in an empty space, in clinical and neurotypical conditions, is crucial. The Enhanced-Baking Tray Task (E-BTT) is as simple as that – placing objects inside a frame as evenly as possible, as if they were “cookies” to be baked i...

How do attention and consciousness interact in the human brain? Rival theories of consciousness disagree on the role of fronto-parietal attentional networks in conscious perception. We recorded neural activity from 727 intracerebral contacts in 13 epileptic patients, while they detected near-threshold targets preceded by attentional cues. Unsupervi...

Understanding how few distributed areas can steer large-scale brain activity is a fundamental question that has practical implications, which range from inducing specific patterns of behavior to counteracting disease. Recent endeavors based on network controllability provided fresh insights into the potential ability of single regions to influence...

In everyday life, information from different cognitive domains - such as visuospatial attention, alertness, and inhibition - needs to be integrated between different brain regions. Early models suggested that completely segregated brain networks control these three cognitive domains. However, more recent accounts, mainly based on neuroimaging data...

Spatial neglect usually concerns left-sided events after right-hemisphere damage. Its anatomical correlates are debated, with evidence suggesting an important role for fronto-parietal white matter disconnections in the right hemisphere. Here, we describe the less frequent occurrence of neglect for right-sided events, observed in three right-handed...

Background and objective: Eye-movement trajectories are rich behavioral data, providing a window on how the brain processes information. We address the challenge of characterizing signs of visuo-spatial neglect from saccadic eye trajectories recorded in brain-damaged patients with spatial neglect as well as in healthy controls during a visual sear...

Most of us can use our “mind’s eye” to mentally visualize things that are not in our direct line of sight, an ability known as visual mental imagery. Extensive left temporal damage can impair patients’ visual mental imagery experience, but the critical locus of lesion is unknown. Our recent meta-analysis of 27 fMRI studies of visual mental imagery...

How do attentional networks influence conscious perception? To answer this question, we used magnetoencephalography in human participants and assessed the effects of spatially nonpredictive or predictive supra-threshold peripheral cues on the conscious perception of near-threshold Gabors. Three main results emerged. (i) As compared with invalid cue...

Spatial cognition is a function that strongly affects adaptation. This is particularly evident when it is impaired, as often happens after brain injury.Neglect, or hemispatial visual neglect, is a dramatic consequence of right hemisphere damage that leads patient to ignore the left, controlateral part of the space. It is assessed with tasks and tes...

The Baking Tray Task is an ecological task developed for the assessment of unilateral neglect that can also be used for research on neurotypical participants. In this task, participants are asked to place 16 objects inside a board as evenly as possible. In the case of impaired spatial exploration, consequent to right attentional networks damage, as...

Visual mental imagery is the faculty whereby we can “visualize” objects that are not in our line of sight. Longstanding evidence dating back over thirty years has shown that unilateral brain lesions, especially in the left temporal lobe, can impair aspects of this ability. Yet, there is currently no attempt to identify analogies between these neuro...

Most of us can use their “mind’s eye” to mentally visualize things that are not in their direct line of sight, an ability known as visual mental imagery. Extensive left temporal damage can impair patients’ visual mental imagery experience, but the critical locus of lesion is unknown. Our recent meta-analysis of 27 fMRI studies of visual mental imag...

Most of us can use their “mind’s eye” to mentally visualize things that are not in their direct line of sight, an ability known as visual mental imagery. Extensive left temporal damage can impair patients’ visual mental imagery experience, but the critical locus of lesion is unknown. Our recent meta-analysis of 27 fMRI studies of visual mental imag...

Spatial neglect usually concerns left-sided events after right hemisphere damage. Its anatomical correlates are debated, with evidence suggesting an important role for fronto-parietal white matter disconnections in the right hemisphere. Here we describe the less frequent occurrence of neglect for right-sided events, observed in three right-handed p...

Spatial neglect after right-hemispheric stroke, characterized by the failure to attend or respond to the contralesional space, is a strong negative outcome predictor. Neglect is a supramodal syn-drome affecting not only the visual but also the auditory modality. Preliminary studies used this audio-visual cross-modal effect to show short-lasting eff...

Brain strokes often induce disabling cognitive deficits. Recent evidence stresses the importance of inter-hemispheric connectivity for recovery from stroke-induced attention deficits. Listening to music induces coordinated bi-hemispheric activity in the neurotypical brain. The following hypotheses are advanced: (1) Connectivity patterns within and...

Small Group presentation about out paper "Visual Neglect After an Isolated Lesion of the Superior Colliculus" doi:10.1001/jamaneurol.2021.3863

The ventral temporal cortex hosts key regions for the high-level visual processing of object shape and color. These areas represent nodes of large-scale neural circuits dedicated to object recognition. In the language-dominant hemisphere, some of these regions communicate with the language systems; by assigning verbal labels to percepts, these circ...

Understanding how few distributed areas can steer large-scale brain activity is a fundamental question that has also practical implications, which range from inducing specific patterns of behavior to counteracting disease. Recent endeavors based on network controllability provided fresh insights on the potential ability of single regions to influen...

Brain strokes often induce disabling cognitive deficits. Recent evidence stresses the importance of inter-hemispheric connectivity for recovery from stroke-induced attention deficits. Listening to music induces coordinated bi-hemispheric activity in the neurotypical brain. The following hypotheses are advanced: (1) Connectivity patterns within and...

Purpose of Review Color provides important information about the identity of the objects we encounter. After early processing stages in the retinal cones, thalamus, and occipital cortex, retinal signals reach the ventral temporal cortex for high-level color and object processing, which links color perception with top-down expectations and knowledge...

Visuospatial orientation of attention is the cognitive process that allows to orient and focus on stimuli presented in the visual field. A cognitive-attentional bias towards one side of the visual field, often the left side, derives from cerebral, evolutionary, and cultural factors. Such a leftward bias is often referred to as "pseudoneglect". Scho...

Visuospatial neglect is a frequent and disabling consequence of injuries to the right hemisphere. Patients with neglect show signs of impaired attention for left-sided events, which depends on dysfunction of fronto-parietal networks. After unilateral injury, such as stroke, these networks and their contralateral homologs can reorganize following mu...

Large-scale neural systems in the human brain allow us to prioritize the processing of external information according to our goals, and to efficiently manage sudden, unforeseen events. At the cortical level, these systems are mainly organized in frontoparietal networks, with some functional and anatomical asymmetries in favor of the right hemispher...

The year 2021 marks the 130th anniversary of the untimely death of Heinrich Lissauer (1861-1891). In his thirty years of life, Lissauer managed to put together an impressive number of contributions to neurology and neuroanatomy. Most influential is his famous distinction between apperceptive and associative forms of visual agnosia. It is perhaps le...

Background and Purpose We used differential actigraphy as a novel, objective method to quantify motor neglect (a clinical condition whereby patients mimic hemiplegia even in the absence of sensorimotor deficits), whose diagnosis is at present highly subjective, based on the clinical observation of patients’ spontaneous motor behavior. Methods Pati...

Riassunto L’aprassia è un deficit acquisito dei movimenti appresi. Tre forme principali di aprassia gestuale sono state descritte all’inizio del XIX secolo da Liepmann: aprassia ideomotoria, ideatoria e melocinetica. Ciascuna di queste aprassie corrisponde a un disturbo selettivo di un aspetto del gesto e a una lesione di una regione cerebrale spec...

Background The measures taken to contain the coronavirus disease 2019 (COVID-19) pandemic, such as the lockdown in Italy, do impact psychological health; yet, less is known about their effect on cognitive functioning. The transactional theory of stress predicts reciprocal influences between perceived stress and cognitive performance. However, the e...

Attention allows us to prioritize the processing of external information according to our goals, but also to cope with sudden, unforeseen events. Attention processes rely on the coordinated activity of large-scale brain networks. At the cortical level, these systems are mainly organized in fronto-parietal networks, with functional and anatomical as...

The dominant neural model of visual mental imagery (VMI) stipulates that memories from the medial temporal lobe acquire sensory features in early visual areas. However, neurological patients with damage restricted to the occipital cortex typically show perfectly vivid VMI, while more anterior damages extending into the temporal lobe, especially in...

Exogenous attention, the process that makes external salient stimuli pop-out of a visual scene, is essential for survival. How attention-capturing events modulate processing dynamics in the human brain remains unclear. We obtained a comprehensive depiction of attentional cortical dynamics at high spatiotemporal resolution, by analyzing brain activi...

Do we need attention to become aware of an external event? We used magnetoencephalography (MEG) in human participants to assess the effects of nonpredictive and predictive supra-threshold peripheral visual cues on the conscious perception of near-threshold Gabor patches. Both nonpredictive and predictive valid cues increased the number of detected...

Most people tend to explore space starting from the left side, a bias that can also be found in cancellation and line bisection tasks. This spatial bias, known as pseudoneglect, is modulated by biological and cultural factors. Traditional paper-and-pencil tests are affected by ecological and sensitivity issues. Recently, we developed an enhanced ve...

Naming a color can be understood as an act of categorization, that is, identifying it as a member of a category of colors that are referred to by the same name. But are naming and categorization equivalent cognitive processes and consequently rely on same neural substrates? Here, we used task and resting-state functional magnetic resonance imaging...

La négligence spatiale est un ensemble de déficits cognitifs qui surviennent souvent après un AVC dans l’hémisphère droit du cerveau. Les patients négligents se comportent comme si la moitié gauche du monde n’existait plus ; ils ont un mauvais pronostic quant à leur récupération fonctionnelle. Il y a un débat dans la littérature sur le rôle de l’hé...

Eye-movement trajectories are rich behavioral data, providing a window onto how the brain processes information. Analyses of these trajectories can be automated and benefit from machine learning algorithms. Among those, deep learning has recently proven very successful, setting new state-of-art results in many computer vision applications, includin...

Objectives Patients with unilateral brain damage may avoid moving the limbs contralateral to their lesion, even in the absence of sensorimotor deficits. However, when asked to move their limbs these patients typically show normal strength and dexterity. In their seminal 1983 article on the Journal of Neurology, Neurosurgery and Psychiatry , Laplane...

Inhibition of return (IOR) refers to the slowing of response times (RTs) for stimuli repeated at previously inspected locations, as compared with novel ones. However, the exact processing stage(s) at which IOR occurs, and its nature across different response modalities, remain debated. We tested predictions on these issues originating from the FORT...

Background The measures taken to contain the COVID-19 pandemic, such as the lockdown in Italy, do impact psychological health; yet, less is known about their effect on cognitive functioning. The transactional theory of stress predicts reciprocal influences between perceived stress and cognitive performance. However, the effects of a period of stres...

Visual neglect is a frequent and disabling consequence of right brain damage. Traditional paper-and pencil tests of neglect have limited sensitivity and ecological validity. The Baking Tray Task (BTT), instead, approaches real-life situations, because it requires participants to place 16 physical objects on a board. The number of objects placed on...

Naming a color can be understood as an act of categorization, i.e. identifying it as a member of category of colors that are referred to by the same name. But are naming and categorization equivalent cognitive processes, and consequently rely on same neural substrates? Here, we used task and resting-state fMRI, as well as behavioral measures to ide...

Please cite this article as: Malkinson TS, Migliaccio R, Migeot H, Picq C, Cerrato A, Pradat-Diehl P, Bartolomeo P, Toba MN, A dissociation between preserved abstract spatial knowledge and impaired navigation in a blind patient, CORTEX, https://doi.

The dominant neural model of visual mental imagery (VMI) stipulates that memories from the medial temporal lobe acquire sensory features in early visual areas. However, neurological patients with damage restricted to the occipital cortex typically show perfectly vivid VMI, while more anterior damages extending into the temporal lobe, especially in...

Large-scale neural systems in the human brain allow us to prioritize the processing of external information according to our goals, and to efficiently manage sudden, unforeseen events. At the cortical level, these systems are mainly organized in fronto-parietal networks, with some functional and anatomical asymmetries in favor of the right hemisphe...

A bstract Visual neglect is a frequent and disabling consequence of right brain damage. Traditional paper-and- pencil tests of neglect have limitations in sensitivity and ecological validity. The Baking Tray Task (BTT), instead, approaches real-life situations, because it requires participants to place 16 physical objects on a board. The number of...

Visual neglect is a frequent and disabling consequence of right brain damage. Traditional paper-and-pencil tests of neglect have limitations in sensitivity and ecological validity. The Baking Tray Task (BTT), instead, approaches real-life situations, because it requires participants to place 16 physical objects on a board. The number of objects pla...

Color provides valuable information about the environment, yet the exact mechanisms explaining how colors appear to us remain poorly understood. Retinal signals are processed in the visual cortex through high-level mechanisms that link color perception with top-down expectations and knowledge. Here, we review the neuroimaging evidence about color p...

We investigated object-colour knowledge in RDS, a patient with impaired colour naming after a left occipito-temporal stroke. RDS’s colour perception, object naming and verbal colour-knowledge (the ability to verbally say the typical colour of an object) were relatively spared. RDS was also able to state if an object was appropriately coloured or no...

Color is continuous, yet we group colors into discrete categories associated with color names (e.g., yellow, blue). Color categorization is a case in point in the debate on how language shapes human cognition. Evidence suggests that color categorization depends on top-down input from the language system to the visual cortex. We directly tested this...

According to some theoretical models, information contained in visual short-term memory (VSTM) consists of two main memory stages/storages: sensory memory, a system wherein information is stored for a brief time with high detail and low resistance to visual interference, and visual working memory, a low-capacity system wherein information is protec...

Visuospatial abilities are framed in the capacity of perceiving, acting and reasoning in function of spatial coordinates, permitting to identify visual and spatial relationships among objects. They represent the set of skills conferring individuals the ability to interact with the surrounding world. Whenever spatial cognition is impaired it is impo...

We used an ad hoc created neuropsychological battery to evaluate in details both verbal and visuospatial working memory (WM) in patients with posterior cortical atrophy (PCA, n = 5). PCA is a rare, early-onset neurodegenerative dementia, often due to Alzheimer’s disease (AD) pathology. Clinically, PCA patients present with visual, visuospatial, and...

How are colour categories related to perception and language? To answer this question, we review research on the neural correlates of colour categories, and categorical responses in preverbal infants and non-human animals. With respect to language, the reviewed findings suggest that colour categorisation often involves automatic language processing...

Résumé Selon J.J. Moreau de Tours (1859) et quelques cliniciens de la fin du xixe siècle, la Paralysie Générale, pendant sa période prodromique, pouvait conférer une créativité exceptionnelle et cette idée était devenue populaire dans le milieu littéraire. Sa validité est examinée à partir de l’exemple, choisi par Moreau de Tours, de son malade le...

We review recent evidence for the hemispheric lateralization of attentional systems in the human brain. There is abundant anatomical, neuroimaging and neuromodulatory evidence for a relative lateralization towards the right hemisphere of some of the cortical networks supporting the attentional systems, especially those including the temporo-parieta...

Visual neglect is a frequent and disabling consequence of right hemisphere damage. Previous work demonstrated a probable role of posterior callosal dysfunction in the chronic persistence of neglect signs. Prism adaptation is a non-invasive and convenient technique to rehabilitate chronic visual neglect, but it is not effective in all patients. Here...

Visual neglect is a frequent and disabling consequence of right hemisphere damage. Previous work demonstrated a probable role of posterior callosal dysfunction in the chronic persistence of neglect signs. Prism adaptation is a non-invasive and convenient technique to rehabilitate chronic visual neglect, but it is not effective in all patients. Here...

Visual neglect is a frequent and disabling consequence of right hemisphere damage. Previous work demonstrated a probable role of posterior callosal dysfunction in the chronic persistence of neglect signs. Prism adaptation is a non-invasive and convenient technique to rehabilitate chronic visual neglect, but it is not effective in all patients. Here...

Confabulating patients produce statements and actions that are unintentionally incongruous to their history, background, present and future situation. Here we present the very unusual case of a patient with right hemisphere damage and signs of left visual neglect, who, when presented with visual stimuli, confabulated both for consciously undetected...

Attention is considered as one of the pre-requisites of conscious perception. Phasic alerting and exogenous orienting improve conscious perception of near-threshold information through segregated brain networks. Using a multimodal neuroimaging approach, combining data from functional MRI (fMRI) and diffusion-weighted imaging (DWI), we investigated...

Attention is considered as one of the pre-requisites of conscious perception. Phasic alerting and exogenous orienting improve conscious perception of nearthreshold information through segregated brain networks. Using a multimodal neuroimaging approach, combining data from functional MRI (fMRI) and diffusion-weighted imaging (DWI), we investigated t...

La corteccia parieto-occipitale del cervello umano contiene complesse reti di regioni cruciali per la percezione visiva e tattile, l’accoppiamento visuomotorio con gli arti e l’orientamento spaziale. Una loro lesione può portare a diversi quadri clinici tipici. Dopo un richiamo dell’anatomia e delle connessioni di queste regioni, questo articolo pa...

Most people tend to bisect horizontal lines slightly to the left of their true center (pseudoneglect), and start visual search from left-sided items. This physiological leftward spatial bias may depend on hemispheric asymmetries in the organization of attentional networks, but the precise mechanisms are unknown. Here we modeled relevant aspects of...

Inhibition of Return (IOR) refers to a slowing of response times (RTs) for visual stimuli repeated at the same spatial location, as compared to stimuli occurring at novel locations. The functional mechanisms and the neural bases of this phenomenon remain debated. Here we present FORTIOR, a model of the cortical control of visual IOR in the human br...

Visual neglect is a disabling consequence of right hemisphere damage, whereby patients fail to detect left-sided objects. Its precise mechanisms are debated, but there is some consensus that distinct component deficits may variously associate and interact in different patients. Here we used a touch-screen based procedure to study two putative compo...

Most people tend to bisect horizontal lines slightly to the left of their true center (pseudoneglect), and start visual search from left-sided items. This physiological leftward spatial bias may depend on hemispheric asymmetries in the organization of attentional networks, but the precise mechanisms are unknown. Here we modeled relevant aspects of...

Supernumerary phantom limb (SPL) designates the experience of an illusory additional limb occurring after brain damage. Functional neuroimaging during SPL movements documented increased response in the ipsilesional supplementary motor area (SMA), premotor cortex (PMC), thalamus and caudate. This suggested that motor circuits are important for bodil...