Franco Lepore

Université de Montréal, Montréal, Quebec, Canada

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Publications (311)994.9 Total impact

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    ABSTRACT: This study assessed whether the neonatal brain recruits different neural networks for native and non-native languages at birth. Twenty-seven one-day-old full-term infants underwent functional near-infrared spectroscopy (fNIRS) recording during linguistic and non-linguistic stimulation. Fourteen newborns listened to linguistic stimuli (native and non-native language stories) and 13 newborns were exposed to non-linguistic conditions (native and non-native stimuli played in reverse). Comparisons between left and right hemisphere oxyhemoglobin (HbO2) concentration changes over the temporal areas revealed clear left hemisphere dominance for native language, whereas non-native stimuli were associated with right hemisphere lateralization. In addition, bilateral cerebral activation was found for non-linguistic stimulus processing. Overall, our findings indicate that from the first day after birth, native language and prosodic features are processed in parallel by distinct neural networks.
    No preview · Article · Feb 2016 · Neuropsychologia
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    ABSTRACT: Early blind individuals are known to exhibit structural brain reorganization. Particularly, early onset blindness may trigger profound brain alterations that affect not only the visual system, but also the remaining sensory systems. Diffusion tensor imaging (DTI) allows in-vivo visualization of brain white matter connectivity, and has been extensively used to study brain white matter structure. Among statistical approaches based on DTI, Tract-Based Spatial Statistics (TBSS) is widely used because of its ability to automatically perform whole brain white matter studies. Tract Specific Analysis (TSA) is a more recent method that localizes changes in specific white matter bundles. Here we compare TBSS and TSA results on DTI scans from 12 early blind subjects and 13 age matched sighted controls, with two aims: 1) to investigate white matter alterations associated with early visual deprivation; 2) to examine the relative sensitivity of TSA when compared to TBSS, for both deficit and hypertrophy of white matter microstructures. Both methods give consistent results for broad white matter regions of deficits. However, TBSS does not detect hypertrophy of white matter, while TSA shows a higher sensitivity in detecting subtle differences in white matter co-localized to the posterior parietal lobe.
    Full-text · Article · Dec 2015 · Neuroreport

  • No preview · Conference Paper · Dec 2015
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    ABSTRACT: Because nervous system development may be affected by prematurity, many prematurely born children present language or cognitive disorders at school age. The goal of this study is to investigate whether these impairments can be identified early in life using electrophysiological auditory event-related potentials (AERPs) and mismatch negativity (MMN). Brain responses to speech and non-speech stimuli were assessed in prematurely born children to identify early electrophysiological markers of language and cognitive impairments. Participants were 74 children (41 full-term, 33 preterm) aged 3, 12, and 36 months. Pre-attentional auditory responses (MMN and AERPs) were assessed using an oddball paradigm, with speech and non-speech stimuli presented in counterbalanced order between participants. Language and cognitive development were assessed using the Bayley Scale of Infant Development, Third Edition (BSID-III). Results show that preterms as young as 3 months old had delayed MMN response to speech stimuli compared to full-terms. A significant negative correlation was also found between MMN latency to speech sounds and the BSID-III expressive language subscale. However, no significant differences between full-terms and preterms were found for the MMN to non-speech stimuli, suggesting preserved pre-attentional auditory discrimination abilities in these children. Identification of early electrophysiological markers for delayed language development could facilitate timely interventions.
    Full-text · Article · Oct 2015 · Neuropsychologia
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    ABSTRACT: Most investigations of visuo-perceptual abilities in the Autism Spectrum (AS) are level-specific, using tasks that selectively solicit either lower- (i.e., spatial frequency sensitivity), mid- (i.e., pattern discrimination) or higher-level processes (i.e., face identification) along the visual hierarchy. Less is known about how alterations at one level of processing (i.e., low-level) interact with that of another (i.e., mid-level). The aim of this study was to assess whether manipulating the physical properties (luminance vs texture) of local contour elements of a mid-level, visual pattern interferes with the discrimination of that pattern in a differential manner for individuals with AS.
    Full-text · Article · Sep 2015 · Neuropsychologia
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    ABSTRACT: The study of sensory deprivation is a striking model to reveal the role experience plays in sculpting the functional architecture of the brain. Here we used functional Magnetic Resonance Imaging to characterize brain responses to auditory stimuli in 11 adults who had been deprived of all patterned vision at birth by dense congenital cataracts in both eyes until they were removed surgically at 9 to 238 days of age. When compared to a control group with typical vision, the cataract-recovery group showed enhanced auditory-driven activity in two focal bilateral visual regions (the superior occipital gyrus and the cuneus) classically considered retinotopic. The crossmodal activation of occipital regions correlated neither with visual acuity nor with the duration of deprivation in the cataract-recovery group. A combination of dynamic causal modeling with Bayesian model selection indicated that this auditory-driven activity in the occipital cortex was better explained by direct cortico-cortical connections with primary auditory cortex than by subcortical reorganizations. These results demonstrate that a short period of visual deprivation during the early sensitive period of brain development leads to enduring large-scale crossmodal reorganization of the brain circuitry typically dedicated to vision. Meeting abstract presented at VSS 2015.
    No preview · Article · Sep 2015 · Journal of Vision
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    ABSTRACT: Animal and human studies have demonstrated that transient visual deprivation early in life, even for a very short period, permanently alters the response properties of neurons in the visual cortex and leads to corresponding behavioral visual deficits [1-7]. While it is acknowledged that early-onset and longstanding blindness leads the occipital cortex to respond to non-visual stimulation [8, 9], it remains unknown whether a short and transient period of postnatal visual deprivation is sufficient to trigger crossmodal reorganization that persists after years of visual experience. In the present study, we characterized brain responses to auditory stimuli in 11 adults who had been deprived of all patterned vision at birth by congenital cataracts in both eyes until they were treated at 9 to 238 days of age. When compared to controls with typical visual experience, the cataract-reversal group showed enhanced auditory-driven activity in focal visual regions. A combination of dynamic causal modeling with Bayesian model selection [10] indicated that this auditory-driven activity in the occipital cortex was better explained by direct cortico-cortical connections with the primary auditory cortex than by subcortical connections. Thus, a short and transient period of visual deprivation early in life leads to enduring large-scale crossmodal reorganization of the brain circuitry typically dedicated to vision. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Full-text · Article · Aug 2015 · Current biology: CB
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    ABSTRACT: To date, very little is known about the normal development trajectory of visual texture segregation, or how it is affected by preterm birth. The goal of this study was to characterize the development of visual texture segregation using texture segregation visual evoked potentials (tsVEPs) in children born full-term and children born preterm without major neurological impairment. Forty-five full-term and 43 preterm children were tested at either 12, 24 or 36 months of age (corrected age for prematurity at 12 and 24 months old). VEPs were obtained using two lower-level stimuli defined by orientation (oriVEP) and two higher-level stimuli defined by texture (texVEP). TsVEP was obtained by dividing by two the subtraction of oriVEP from texVEP. Results show a clear maturation of the processes underlying visual texture segregation in the full-term group, with a significant N2 latency reduction between 12 and 36 months of age for all conditions. Significant N2 amplitude reduction was observed for oriVEP between 12 and 24 months, as well as for texVEP between 12 and 24 months, and 12 and 36 months. Comparison between full-term and preterm children indicated significantly lower N2 amplitude for the preterm group at 12 months for oriVEP and texVEP. These differences were no longer apparent at 24 months of age, suggesting that children born preterm catch up with their full-term counterparts somewhere between 12 and 24 months of age. Our results appear to reflect a maturational delay in preterm children in both lower-level and higher-level visual processing during, at least, early childhood. Copyright © 2015. Published by Elsevier Ltd.
    Full-text · Article · May 2015 · Vision research
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    ABSTRACT: Unilateral hippocampal atrophy (HA) is considered as a precursor of mesial temporal sclerosis (MTS) in some patients with temporal lobe epilepsy. However, in other cases, it has been suggested that HA without MTS may constitute a distinct epileptic entity. Hippocampal atrophy without MTS was defined as HA without T2-weighted hyperintensity, loss of internal architecture, or associated lesion seen on the MRI data. To date, no study has focused on the cognitive pattern of children with epilepsy with HA without MTS. The objectives of the present study were to characterize the cognitive profile of these children and to investigate the presence (or the absence) of material-specific memory deficits in these young patients, as found in patients with MTS. Toward this end, 16 young patients with epilepsy with either left or right HA without MTS completed a set of neuropsychological tests, assessing overall intelligence, verbal memory and nonverbal memory, and some aspects of attention and executive functions. Results showed normal intellectual functioning without specific memory deficits in these patients. Furthermore, comparison between patients with left HA and patients with right HA failed to reveal a material-specific lateralized memory pattern. Instead, attention and executive functions were found to be impaired in most patients. These results suggest that HA may constitute a distinct epileptic entity, and this information may help health-care providers initiate appropriate and timely interventions.
    No preview · Article · Mar 2015 · Epilepsy & Behavior
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    ABSTRACT: The insula has been implicated in social cognition and empathy in several neuroimaging paradigms. Impairments in social information processing, including specific deficits in disgust recognition, have been described following isolated insular damage, although the evidence remains limited to a few case studies. The present study examines social cognition and empathy in a group of fifteen patients for whom the insula was removed as part of their epilepsy surgery. These patients were compared to a lesion-control group of 15 epileptic patients who had a surgery in the anterior temporal lobe that spared the insula, and to 20 healthy volunteers matched on age, sex, and education. Participants were assessed on an Emotion Recognition Task (ERT), the Reading the Mind in the Eyes test, and a self-administered empathy questionnaire. Patients who underwent insular resection showed poorer ability to recognize facial expressions of emotions and had lower scores of perspective taking on the empathy questionnaire than healthy controls. Using results from healthy controls as normative data, emotion recognition deficits were more frequent in insular patients than in both other groups. Specific emotion analyses revealed impairments in fear recognition in both groups of patients, whereas happiness and surprise recognition was only impaired in patients with insular resection. There was no evidence for a deficit in disgust recognition. The findings suggest that unilateral damage to the operculo-insular region may be associated with subtle impairments in emotion recognition, and provide further clinical evidence of a role of the insula in empathic processes. However, the description of 15 consecutive cases of insula-damaged patients with no specific deficit in disgust recognition seriously challenges the assumptions, based on previous case reports, that the insula is specifically involved in disgust processing. Copyright © 2015. Published by Elsevier Ltd.
    No preview · Article · Mar 2015 · Neuropsychologia
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    ABSTRACT: Resection of the insular cortex is becoming more frequent as it is increasingly recognized that a nonnegligible proportion of surgical candidates with drug-resistant epilepsy have an epileptogenic zone that involves the insula. In the last decades, however, the insula has been proposed to be involved in several neuropsychological functions, and there is a lack of documentation on whether partial or complete insulectomy results in permanent cognitive impairments in this clinical population. In this study, we conducted standard preoperative and postoperative neuropsychological assessments in 18 patients undergoing epilepsy surgery that included the removal of the insula in the right (n = 13) or the left (n = 5) hemisphere. Postoperative testing was conducted at least five months after surgery. Cognitive impairments were common and heterogeneous prior to surgery, with language and verbal memory impairments being especially frequent among patients in whom epileptic seizures originated from the left hemisphere. After surgery, declines and improvements occurred on a variety of outcomes, although new deficits were relatively infrequent among patients who had obtained normal performance at baseline. Statistical comparisons between preoperative and postoperative assessments revealed significant deterioration of only one outcome – the color naming condition of the Stroop test – which relies on oro-motor speed and lexical access. These findings suggest that partial or complete resection of the insular cortex in patients with drug-refractory epilepsy can be conducted without major permanent neuropsychological impairments in a vast majority of patients. However, small decrements in specific cognitive functions can be expected, which should also be taken into account when considering the surgical option in this clinical population.
    No preview · Article · Feb 2015 · Epilepsy & Behavior
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    ABSTRACT: The insula is a multisensory area involved in various brain functions, including central auditory processing. However, its specific role in auditory function remains unclear. Here we report three cases of persistent hypersensitivity to auditory stimuli following damage to the insular cortex, using behavioral and neurophysiological measures. Two patients who complained of auditory disturbance since they suffered an isolated unilateral insular stroke, and one epileptic patient who underwent right insular resection for control of drug-resistant seizures, were involved in this study. These patients, all young adult women, were tested for auditory function more than one year after brain injury, and were compared to 10 healthy control participants matched for age, sex, and education. The assessment included pure-tone detection and speech detection in quiet, loudness discomfort levels, random gap detection, recognition of frequency and duration patterns, binaural separation, dichotic listening, as well as late-latency auditory event-related potentials (ERPs). Each patient showed mild or moderate hyperacusis, as revealed by decreased loudness discomfort levels, which was more important on the side of lesion in two cases. Tests of temporal processing also revealed impairments, in concordance with previous findings. ERPs of two patients were characterised by increased amplitude of the P3b component elicited during a two-tone auditory oddball detection task. This study is the first to report cases of persistent hyperacusis following damage to the insular cortex, and suggests that the insula is involved in modulating the perceived intensity of the incoming auditory stimuli during late-stage processing. Copyright © 2015. Published by Elsevier B.V.
    Full-text · Article · Feb 2015 · Brain Research
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    ABSTRACT: Blindness represents a unique model to study how visual experience may shape the development of brain organization. Exploring how the structure of the corpus callosum (CC) reorganizes ensuing visual deprivation is of particular interest due to its important functional implication in vision (e.g., via the splenium of the CC). Moreover, comparing early versus late visually deprived individuals has the potential to unravel the existence of a sensitive period for reshaping the CC structure. Here, we develop a novel framework to capture a complete set of shape differences in the CC between congenitally blind (CB), late blind (LB) and sighted control (SC) groups. The CCs were manually segmented from T1-weighted brain MRI and modeled by 3D tetrahedral meshes. We statistically compared the combination of local area and thickness at each point between subject groups. Differences in area are found using surface tensor-based morphometry; thickness is estimated by tracing the streamlines in the volumetric harmonic field. Group differences were assessed on this combined measure using Hotelling’s T 2 test. Interestingly, we observed that the total callosal volume did not differ between the groups. However, our fine-grained analysis reveals significant differences mostly localized around the splenium areas between both blind groups and the sighted group (general effects of blindness) and, importantly, specific dissimilarities between the LB and CB groups, illustrating the existence of a sensitive period for reorganization. The new multivariate statistics also gave better effect sizes for detecting morphometric differences, relative to other statistics. They may boost statistical power for CC morphometric analyses.
    Full-text · Article · Feb 2015 · Neuroinformatics
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    ABSTRACT: The development of language hemispheric specialization is not well understood in young children, especially regarding expressive language functions. In this study, we investigated age-related changes in expressive language lateralization patterns in a population of children (3–6 and 7–10 years old), adolescents (11–16 years old), and young adults (19–30 years old). During functional near-infrared spectroscopy recordings, all participants performed a verbal fluency task, which consisted in naming as many words as possible belonging to a given semantic category. Hemoglobin concentration changes were measured in bilateral frontal and temporal cortical areas. During the language task, results showed a strong left hemisphere response along with weaker right hemisphere activation in all groups. Age-related increases in hemodynamic responses were found bilaterally, with younger children showing smaller hemodynamic responses than adolescents and adults in both hemispheres. Overall, these findings confirm that a left hemisphere specialization is already established in young children and persists through adulthood. Early left hemisphere specialization for expressive language suggests that language development hinges on structural and functional properties of the human brain with little reorganization occurring with development.
    Full-text · Article · Jan 2015 · Neuropsychologia
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    ABSTRACT: Cochlear implant users show a profile of residual, yet poorly understood, musical abilities. An ability that has received little to no attention in this population is entrainment to a musical beat. We show for the first time that a heterogeneous group of cochlear implant users is able to find the beat and move their bodies in time to Latin Merengue music, especially when the music is presented in unpitched drum tones. These findings not only reveal a hidden capacity for feeling musical rhythm through the body in the deaf and hearing impaired population, but illuminate promising avenues for designing early childhood musical training that can engage implanted children in social musical activities with benefits potentially extending to non-musical domains.
    Full-text · Article · Jan 2015 · Hearing Research
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    ABSTRACT: Visual deprivation leads to massive reorganization in both the structure and function of the occipital cortex, raising crucial challenges for sight-restoration. We tracked the behavioral, structural and neurofunctional changes occurring in an early and severely visually impaired patient before, 1.5 and 7 months after sight restoration using magnetic resonance imaging. Robust pre-surgical auditory responses were found in occipital cortex despite residual preoperative vision. In primary visual cortex, crossmodal auditory responses overlapped with visual responses and remained elevated even 7 months post-surgery. However, these crossmodal responses decreased in extrastriate occipital regions after surgery, together with improved behavioral vision and with increases in both grey matter density and neural activation in low-level visual regions. Selective responses in high-level visual regions involved in motion and face processing were observable even pre-surgery and did not evolve after surgery. Taken together, these findings demonstrate that structural and functional reorganization of occipital regions are present in an individual with a longstanding history of severe visual impairment, and that such reorganizations can be partially reversed by visual restoration in adulthood. Copyright © 2014, Journal of Neurophysiology.
    Full-text · Article · Dec 2014 · Journal of Neurophysiology
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    ABSTRACT: The trigeminal system is a chemical sense allowing for the perception of chemosensory information in our environment. However, contrary to smell and taste, we lack a thorough understanding of the trigeminal processing of mixtures. We, therefore, investigated trigeminal perception using mixtures of 3 relatively receptor-specific agonists together with one control odor in different proportions to determine basic perceptual dimensions of trigeminal perception. We found that 4 main dimensions were linked to trigeminal perception: sensations of intensity, warmth, coldness, and pain. We subsequently investigated perception of binary mixtures of trigeminal stimuli by means of these 4 perceptual dimensions using different concentrations of a cooling stimulus (eucalyptol) mixed with a stimulus that evokes warmth perception (cinnamaldehyde). To determine if sensory interactions are mainly of central or peripheral origin, we presented stimuli in a physical "mixture" or as a "combination" presented separately to individual nostrils. Results showed that mixtures generally yielded higher ratings than combinations on the trigeminal dimensions "intensity," "warm," and "painful," whereas combinations yielded higher ratings than mixtures on the trigeminal dimension "cold." These results suggest dimension-specific interactions in the perception of trigeminal mixtures, which may be explained by particular interactions that may take place on peripheral or central levels. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
    Full-text · Article · Dec 2014 · Chemical Senses
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    Yann Harel · Franco Lepore · Fabien D'Hondt
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    ABSTRACT: Le décodage rapide de l'émotion exprimée par un visage est une habileté capitale dans l'établissement d’interactions sociales appropriées. Plusieurs études suggèrent que ce décodage rapide des expressions faciales émotionnelles reposerait sur une analyse visuelle grossière dépendant des voies magnocellulaires qui prennent en charge majoritairement les informations de basse fréquence spatiale. Néanmoins, la contribution relative des voies magnocellulaires et parvocellulaires (qui prennent en charge majoritairement les informations de haute fréquence spatiale) au traitement émotionnel demeure peu connue à ce jour. Cette étude vise donc à clarifier le rôle des basses et des hautes fréquences spatiales dans le décodage des expressions faciales émotionnelles. Nous avons utilisé une tâche de type oddball émotionnel avec 3 conditions de filtrage spatial appliqué aux stimuli : passe-haut (>6cpd), passe-bas (<2cpd), ou non-filtrés. Lors de cette tâche, les potentiels évoqués cognitifs des participants ainsi que leurs temps de réponses furent enregistrés. Une expérimentation préliminaire a été conduite auprès de 5 participants. Au niveau comportemental, nous avons observé des temps de réponse significativement plus courts pour la détection de l’expression faciale de joie en hautes fréquences spatiales. Néanmoins, l’analyse des potentiels évoqués (P100, N170 et P3b) a révélé une tendance à un effet spécifique des expressions faciales émotionnelles sur la latence de la P100 et de la N170 lorsque les basses fréquences spatiales sont présentes. Ces résultats préliminaires suggèrent donc que les informations de basse fréquence spatiale ont un rôle crucial dans les étapes précoces de traitement des expressions faciales émotionnelles mais également que le rôle des basses et hautes fréquences spatiales pourraient différer selon la valence émotionnelle. L'impact potentiel des différentes sous-catégories d'anxiété (anxiété sociale, anxiété-trait ou anxiété-état) sur la contribution des basses et des hautes fréquences spatiales dans le décodage des émotions sera abordé.
    Full-text · Conference Paper · Nov 2014
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    ABSTRACT: The aim of this semilongitudinal study was to investigate the development of central visual pathways in children born preterm but without major neurologic impairments and to establish their cognitive and behavioral profile at school age. Ten children born preterm were assessed at 6 months and at school age, using visual evoked potentials at both time points and cognitive and behavioral tests at school age. We also tested 10 age-matched children born full-term. At 6 months' corrected age, we found no significant differences between preterm and full-term groups for either amplitude or latency of N1 and P1 components. At school age, the preterm group manifested significantly higher N1 amplitudes and tended to show higher P1 amplitudes than the full-term group. We found no significant differences in cognitive and behavioral measures at school age. These results suggest that preterm birth affects visual pathways development, yet the children born preterm did not manifest cognitive problems. © The Author(s) 2014.
    Full-text · Article · Nov 2014 · Journal of Child Neurology
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    ABSTRACT: Though a clear interaction between finger and number representations has been demonstrated, what drives the development of this intertwining remains unclear. Here we tested early blind, late blind and sighted control participants in two counting tasks, each performed under three different conditions: a resting condition, a condition requiring hands movements and a condition requiring feet movements. In the resting condition, every sighted and late blind spontaneously used their fingers, while the majority of early blind did not. Sighted controls and late blind were moreover selectively disrupted by the interfering hand condition, while the early blind who did not use the finger-counting strategy remained unaffected by the interference conditions. These results therefore demonstrate that visual experience plays an important role in implementing the sensori-motor habits that drive the development of finger–number interactions.
    Full-text · Article · Oct 2014 · Cognition

Publication Stats

5k Citations
994.90 Total Impact Points

Institutions

  • 1971-2015
    • Université de Montréal
      • • Centre de Recherche en Neuropsychologie et Cognition (CERNEC)
      • • Department of Psychology
      • • School of Optometry
      Montréal, Quebec, Canada
  • 1988-2012
    • Université du Québec à Montréal
      • • Department of Psychology
      • • Department of Kinanthropology
      Montréal, Quebec, Canada
  • 2006-2011
    • McGill University
      • Douglas Research Centre
      Montréal, Quebec, Canada
  • 2004-2008
    • CHU Sainte-Justine
      Montréal, Quebec, Canada
  • 1974-1995
    • Università di Pisa
      Pisa, Tuscany, Italy
  • 1994
    • Dalhousie University
      Halifax, Nova Scotia, Canada
  • 1981-1987
    • Université du Québec à Trois-Rivières
      • Département de Psychologie
      Trois-Rivières, Quebec, Canada
  • 1984
    • Natural Sciences and Engineering Research Council of Canada
      Mississauga, Ontario, Canada
  • 1978
    • Istituto di Bioimmagini e Fisiologia Molecolare
      Segrate, Lombardy, Italy
    • University of Pennsylvania
      • The Mahoney Institute of Neurological Sciences
      Filadelfia, Pennsylvania, United States