Are Face and Object Recognition Independent? A Neurocomputational Modeling Exploration

Are face and object recognition abilities independent? Although it is commonly believed that they are, Gauthier et al.(2014) recently showed that these abilities become more correlated as experience with nonface categories increases. They argued that there is a single underlying visual ability, v, that is expressed in performance with both face and nonface categories as experience grows. Using the Cambridge Face Memory Test and the Vanderbilt Expertise Test, they showed that the shared variance between Cambridge Face Memory Test and Vanderbilt Expertise Test performance increases monotonically as experience increases. Here, we address why a shared resource across different visual domains does not lead to competition and to an inverse correlation in abilities? We explain this conundrum using our neurocomputational model of face and object processing (The Model, TM). Our results show that, as in the behavioral data, the correlation between subordinate level face and object recognition accuracy increases as experience grows. We suggest that different domains do not compete for resources because the relevant features are shared between faces and objects. The essential power of experience is to generate a "spreading transform" for faces that generalizes to objects that must be individuated. Interestingly, when the task of the network is basic level categorization, no increase in the correlation between domains is observed. Hence, our model predicts that it is the type of experience that matters and that the source of the correlation is in the fusiform face area, rather than in cortical areas that subserve basic level categorization. This result is consistent with our previous modeling elucidating why the FFA is recruited for novel domains of expertise (Tong et al., 2008)

Visual appearance interacts with conceptual knowledge in object recognition

Objects contain rich visual and conceptual information, but do these two types of information interact? Here, we examine whether visual and conceptual information interact when observers see novel objects for the first time. We then address how this interaction influences the acquisition of perceptual expertise. We used two types of novel objects (Greebles), designed to resemble either animals or tools, and two lists of words, which described non-visual attributes of people or man-made objects. Participants first judged if a word was more suitable for describing people or objects while ignoring a task-irrelevant image, and showed faster responses if the words and the unfamiliar objects were congruent in terms of animacy (e.g., animal-like objects with words that described human). Participants then learned to associate objects and words that were either congruent or not in animacy, before receiving expertise training to rapidly individuate the objects. Congruent pairing of visual and conceptual information facilitated observers' ability to become a perceptual expert, as revealed in a matching task that required visual identification at the basic or subordinate levels. Taken together, these findings show that visual and conceptual information interact at multiple levels in object recognition

Le processus de rétablissement de personnes qui ont développé un trouble mental après avoir été victimes de crimes violents

Chaque année au Québec, les crimes violents touchent 1 personne sur 20, la majorité des victimes étant des femmes. Ces crimes ont des conséquences importantes. Ils sont associés à de l’évitement, de la méfiance, à la difficulté à refaire confiance à autrui, ainsi qu’à un plus grand risque de développer un trouble mental (Norris et Kanisasty, 1994; Organisation mondiale de la santé [OMS], 2013). Plusieurs facteurs pourraient influencer le parcours de rétablissement de ces victimes. Le soutien social et la résilience ont été identifiés comme étant des facteurs clés aidant au rétablissement de personnes ayant des troubles mentaux (Caron et Guay, 2005; Duplantier, 2011), mais peu d’études ont posé un regard sur le rétablissement des personnes victimes de crimes violents ayant développé des troubles mentaux et encore moins sur le soutien social qu’elles ont exprimé avoir reçu. Cette recherche a ainsi pour objectif de documenter le processus de rétablissement des personnes victimes de crimes violents qui ont développé un trouble mental. Plus particulièrement, elle mettra en lumière la contribution du soutien social et de la résilience dans ce processus. Afin de répondre aux objectifs de l’étude, un devis descriptif mixte, avec une majeure qualitative, a été privilégié. Au total, huit personnes, dont 7 femmes et 1 homme dont l’âge moyen est de 44 ans (ET=12,47) ont accepté de participer à l’étude. La majorité de ces participantes ont été volontairement recrutées dans un Centre d’aide pour les victimes d’actes criminels (CAVAC). Afin d’explorer et de documenter les parcours de rétablissement des participantes, une entrevue semi-dirigée a été réalisée et trois questionnaires auto-rapportés ont été administrés. L’analyse des données qualitatives et quantitatives indique que les participantes de l’étude ont cheminé dans le rétablissement de leur trouble mental et que des personnes significatives présentes au sein de leur réseau social les ont aidées à se sentir considérées, reconnues et valorisées. Enfin, le soutien offert par les ressources d’aide, notamment celles du système judiciaire, a parfois aidé et a d’autres fois nui à leur rétablissement. La revictimisation, la lourdeur du système de justice ainsi que le soutien offert par la famille ont été les principaux facteurs identifiés par les répondantes comme n’ayant pas su répondre à leurs besoins. Pour les participantes pour qui le soutien social semble avoir le moins contribué à leur cheminement, la capacité de résilience a été un facteur clé qui leur a permis de limiter l’effet du crime subi sur leur bien-être. Ces résultats doivent être interprétés en considérant les limites et forces de cette étude. Le petit échantillon de participantes1 volontaires (n = 8), recrutées au sein d’un seul milieu, témoigne d’une réalité restreinte qui pourrait s’avérer biaisée, notamment en raison de la non atteinte de la saturation empirique des données. Malgré cette limite, cette étude présente des forces notamment quant aux retombées pour la recherche et la pratique. Elle soulève l’importance de la qualité des liens sociaux pour soutenir les personnes victimes de crimes violents dans leur rétablissement. Un réseau de soutien social optimisé par des interventions pourrait faciliter le rétablissement et aider à renforcer le sentiment de protection fragilisé par les violences vécues. Développer des interventions favorisant la capacité de résilience pourrait aussi être un facteur clé prédisposant les victimes à pouvoir compter sur l’autre de nouveau

Mere Exposure Alters Category Learning of Novel Objects

We investigated how mere exposure to complex objects with correlated or uncorrelated object features affects later category learning of new objects not seen during exposure. Correlations among pre-exposed object dimensions influenced later category learning. Unlike other published studies, the collection of pre-exposed objects provided no information regarding the categories to be learned, ruling out unsupervised or incidental category learning during pre-exposure. Instead, results are interpreted with respect to statistical learning mechanisms, providing one of the first demonstrations of how statistical learning can influence visual object learning

Beyond Shape: How You Learn about Objects Affects How They Are Represented in Visual Cortex

Background: Experience can alter how objects are represented in the visual cortex. But experience can take different forms. It is unknown whether the kind of visual experience systematically alters the nature of visual cortical object representations. Methodology/Principal Findings: We take advantage of different training regimens found to produce qualitatively different types of perceptual expertise behaviorally in order to contrast the neural changes that follow different kinds of visual experience with the same objects. Two groups of participants went through training regimens that required either subordinate-level individuation or basic-level categorization of a set of novel, artificial objects, called ‘‘Ziggerins’’. fMRI activity of a region in the right fusiform gyrus increased after individuation training and was correlated with the magnitude of configural processing of the Ziggerins observed behaviorally. In contrast, categorization training caused distributed changes, with increased activity in the medial portion of the ventral occipito-temporal cortex relative to more lateral areas. Conclusions/Significance: Our results demonstrate that the kind of experience with a category of objects can systematically influence how those objects are represented in visual cortex. The demands of prior learning experience therefore appear t

Category-Specific Responses to Faces and Objects in Primate Auditory Cortex

Auditory and visual signals often occur together, and the two sensory channels are known to influence each other to facilitate perception. The neural basis of this integration is not well understood, although other forms of multisensory influences have been shown to occur at surprisingly early stages of processing in cortex. Primary visual cortex neurons can show frequency-tuning to auditory stimuli, and auditory cortex responds selectively to certain somatosensory stimuli, supporting the possibility that complex visual signals may modulate early stages of auditory processing. To elucidate which auditory regions, if any, are responsive to complex visual stimuli, we recorded from auditory cortex and the superior temporal sulcus while presenting visual stimuli consisting of various objects, neutral faces, and facial expressions generated during vocalization. Both objects and conspecific faces elicited robust field potential responses in auditory cortex sites, but the responses varied by category: both neutral and vocalizing faces had a highly consistent negative component (N100) followed by a broader positive component (P180) whereas object responses were more variable in time and shape, but could be discriminated consistently from the responses to faces. The face response did not vary within the face category, i.e., for expressive vs. neutral face stimuli. The presence of responses for both objects and neutral faces suggests that auditory cortex receives highly informative visual input that is not restricted to those stimuli associated with auditory components. These results reveal selectivity for complex visual stimuli in a brain region conventionally described as non-visual “unisensory” cortex

A simple high efficiency intra-islet transduction protocol using lentiviral vectors

Successful normalization of blood glucose in patients transplanted with pancreatic islets isolated from cadaveric donors established the proof-of-concept that Type 1 Diabetes Mellitus is a curable disease. Nonetheless, major caveats to the widespread use of this cell therapy approach have been the shortage of islets combined with the low viability and functional rates subsequent to transplantation. Gene therapy targeted to enhance survival and performance prior to transplantation could offer a feasible approach to circumvent these issues and sustain a durable functional β-cell mass in vivo. However, efficient and safe delivery of nucleic acids to intact islet remains a challenging task. Here we describe a simple and easy-to-use lentiviral transduction protocol that allows the transduction of approximately 80 % of mouse and human islet cells while preserving islet architecture, metabolic function and glucose-dependent stimulation of insulin secretion. Our protocol will facilitate to fully determine the potential of gene expression modulation of therapeutically promising targets in entire pancreatic islets for xenotransplantation purposes

Evaluating assumptions of scales for subjective assessment of thermal environments – Do laypersons perceive them the way, we researchers believe?

International audienc

Sustained blood glutamate scavenging enhances protection in ischemic stroke

Stroke is a major cause of morbidity, mortality, and disability. During ischemic stroke, a marked and prolonged rise of glutamate concentration in the brain causes neuronal cell death. This study explores the protective effect of a bioconjugate form of glutamate oxaloacetate transaminase (hrGOT), which catalyzes the depletion of blood glutamate in the bloodstream for ~6 days following a single administration. When treated with this bioconjugate, a significant reduction of the infarct volume and a better retention of sensorimotor function was observed for ischemic rats compared to those treated with saline. Moreover, the equivalent dose of native hrGOT yielded similar results to the saline treated group for some tests. Targeting the bioconjugate to the blood-brain-barrier did not improve its performance. The data suggest that the bioconjugates draw glutamate out of the brain by displacing homeostasis between the different glutamate pools of the body

NR5A2/LRH-1 regulates the PTGS2-PGE2-PTGER1 pathway contributing to pancreatic islet survival and function

LRH-1/NR5A2 is implicated in islet morphogenesis postnatally, and its activation using the agonist BL001 protects islets against apoptosis, reverting hyperglycemia in mouse models of Type 1 Diabetes Mellitus. Islet transcriptome profiling revealed that the expression of PTGS2/COX2 is increased by BL001. Herein, we sought to define the role of LRH-1 in postnatal islet morphogenesis and chart the BL001 mode of action conferring beta cell protection. LRH-1 ablation within developing beta cells impeded beta cell proliferation, correlating with mouse growth retardation, weight loss, and hypoglycemia leading to lethality. LRH-1 deletion in adult beta cells abolished the BL001 antidiabetic action, correlating with beta cell destruction and blunted Ptgs2 induction. Islet PTGS2 inactivation led to reduced PGE levels and loss of BL001 protection against cytokines as evidenced by increased cytochrome c release and cleaved-PARP. The PTGER1 antagonist—ONO-8130—negated BL001-mediated islet survival. Our results define the LRH-1/PTGS2/PGE/PTGER1 signaling axis as a key pathway mediating BL001 survival properties.The authors are supported by grants from the Consejería de Salud, Fundación Pública Andaluza Progreso y Salud, Junta de Andalucía (PI-0727-2010 to B.R.G., PI-0085-2013 to P.I.L., PI-0247-2016 to F.J.B.S.), the Consejería de Economía, Innovación y Ciencia (P10.CTS.6359 to B.R.G.), the Ministerio de Ciencia e Innovación co-funded by Fondos FEDER (PI10/00871, PI13/00593 and BFU2017-83588-P to B.R.G and PI17/01004 to F.J.B.S.), Vencer el Cancer (B.R.G), DiabetesCero (B.R.G.) and the Juvenile Diabetes Research Foundation Ltd (17-2013-372 and 2-SRA-2019-837-S-B to B.R.G.). E.M.V. is recipient of a Fellowship from the Ministerio de Ciencia e Innovación co-funded by Fondos FEDER (PRE2018-084907). F.J.B.S. is a recipient of a "Nicolás Monardes" research contracts from Consejería de Salud Junta de Andalucía, (C-0070-2012). A.M.M. is supported by CPII19/00023 and PI18/01590 from the Instituto de Salud Carlos III co-funded by Fondos FEDER. V.C. is supported by a AECC investigator award. CIBERDEM is an initiative of the Instituto de Salud Carlos III