The Experts below are selected from a list of 328182 Experts worldwide ranked by ideXlab platform
Jason J S Barton - One of the best experts on this subject based on the ideXlab platform.
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Perceptual and anatomic patterns of selective deficits in facial identity and expression Processing
Neuropsychologia, 2011Co-Authors: Christopher J Fox, Giuseppe Iaria, Hashim M Hanif, Bradley Duchaine, Jason J S BartonAbstract:Whether a single perceptual process or separate and possibly independent processes support facial identity and expression recognition is unclear. We used a morphed-face discrimination test to examine sensitivity to facial expression and identity information in patients with occipital or temporal lobe damage, and structural and functional MRI to correlate behavioral deficits with damage to the core regions of the face-Processing Network. We found selective impairments of identity perception in two patients with right inferotemporal lesions and two prosopagnosic patients with damage limited to the anterior temporal lobes. Of these four patients one exhibited damage to the right fusiform and occipital face areas, while the remaining three showed sparing of these regions. Thus impaired identity perception can occur with damage not only to the fusiform and occipital face areas, but also to other medial occipitotemporal structures that likely form part of a face recognition Network. Impaired expression perception was seen in the fifth patient with damage affecting the face-related portion of the posterior superior temporal sulcus. This subject also had difficulty in discriminating identity when irrelevant variations in expression needed to be discounted. These neuropsychological and neuroimaging data provide evidence to complement models which address the separation of expression and identity perception within the face-Processing Network.
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defining the face Processing Network optimization of the functional localizer in fmri
Human Brain Mapping, 2009Co-Authors: Christopher J Fox, Giuseppe Iaria, Jason J S BartonAbstract:Functional localizers that contrast brain signal when viewing faces versus objects are commonly used in functional magnetic resonance imaging studies of face Processing. However, current protocols do not reliably show all regions of the core system for face Processing in all subjects when conservative statistical thresholds are used, which is problematic in the study of single subjects. Furthermore, arbitrary variations in the applied thresholds are associated with inconsistent estimates of the size of face-selective regions-of-interest (ROIs). We hypothesized that the use of more natural dynamic facial images in localizers might increase the likelihood of identifying face-selective ROIs in individual subjects, and we also investigated the use of a method to derive the statistically optimal ROI cluster size independent of thresholds. We found that dynamic facial stimuli were more effective than static stimuli, identifying 98% (versus 72% for static) of ROIs in the core face Processing system and 69% (versus 39% for static) of ROIs in the extended face Processing system. We then determined for each core face Processing ROI, the cluster size associated with maximum statistical face-selectivity, which on average was approximately 50 mm(3) for the fusiform face area, the occipital face area, and the posterior superior temporal sulcus. We suggest that the combination of (a) more robust face-related activity induced by a dynamic face localizer and (b) a cluster-size determination based on maximum face-selectivity increases both the sensitivity and the specificity of the characterization of face-related ROIs in individual subjects.
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the correlates of subjective perception of identity and expression in the face Network an fmri adaptation study
NeuroImage, 2009Co-Authors: So Young Moon, Giuseppe Iaria, Jason J S BartonAbstract:The recognition of facial identity and expression are distinct tasks, with current models hypothesizing anatomic segregation of Processing within a face-Processing Network. Using fMRI adaptation and a region-of-interest approach, we assessed how the perception of identity and expression changes in morphed stimuli affected the signal within this Network, by contrasting (a) changes that crossed categorical boundaries of identity or expression with those that did not, and (b) changes that subjects perceived as causing identity or expression to change, versus changes that they perceived as not affecting the category of identity or expression. The occipital face area (OFA) was sensitive to any structural change in a face, whether it was identity or expression, but its signal did not correlate with whether subjects perceived a change or not. Both the fusiform face area (FFA) and the posterior superior temporal sulcus (pSTS) showed release from adaptation when subjects perceived a change in either identity or expression, although in the pSTS this effect only occurred when subjects were explicitly attending to expression. The middle superior temporal sulcus (mSTS) showed release from adaptation for expression only, and the precuneus for identity only. The data support models where the OFA is involved in the early perception of facial structure. However, evidence for a functional overlap in the FFA and pSTS, with both identity and expression signals in both areas, argues against a complete independence of identity and expression Processing in these regions of the core face-Processing Network.
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disconnection in prosopagnosia and face Processing
Cortex, 2008Co-Authors: Giuseppe Iaria, Jason J S BartonAbstract:Face perception is a function with significant complexity, reflected in cognitive models that propose a hierarchy of parallel and serial Processing stages. Current neuroimaging data also show that face perception involves a core Processing Network of cortical modules, which are likely specialized for different functions involved in face Processing. The core face Processing Network is further linked to an extended face Processing Network which is not solely involved in the perception of faces, but rather contains modules mediating the Processing of semantic, biographic and emotional information about people. The segregation of these processes within discrete anatomic regions creates the potential for disconnection between regions to generate neuropsychological deficits involving faces. In this review we consider the types of disconnection possible both within the core face Processing system and between the core and extended systems, the pattern of deficits that would be considered as evidence of such disconnections, the potential anatomy of lesions that would create them, and whether any cases exist that meet these criteria.
Fengqi You - One of the best experts on this subject based on the ideXlab platform.
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manufacturing ethylene from wet shale gas and biomass comparative technoeconomic analysis and environmental life cycle assessment
Industrial & Engineering Chemistry Research, 2018Co-Authors: Minbo Yang, Xueyu Tian, Fengqi YouAbstract:This paper presents comparative technoeconomic and environmental analyses of three ethylene manufacturing pathways based on ethane-rich shale gas, corn stover, and corn grain. The shale-gas-based pathway includes two Processing steps, namely, shale gas Processing to produce ethane and ethane steam cracking to manufacture ethylene. The two biomass-based pathways also contain two Processing steps each, namely, bioethanol production via fermentation and ethylene manufacturing via bioethanol dehydration. A distributed–centralized Processing Network that consists of distributed ethane/bioethanol production and centralized ethylene manufacturing is employed for each of the three pathways. Detailed process simulation models are developed for major Processing steps, and the three pathways are then modeled on five different ethylene production scales. On the basis of the detailed mass and energy balances and life cycle inventory results, we conduct technoeconomic and life cycle analyses to systematically compare t...
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comparative life cycle assessment of ethylene from wet shale gas and biomass
2018Co-Authors: Minbo Yang, Xueyu Tian, Fengqi YouAbstract:Abstract This paper presents comparative techno-economic and environmental analyses of three ethylene manufacturing pathways based on wet shale gas, corn stover, and corn grain. A distributed-centralized Processing Network that consists of distributed ethane/bioethanol production and centralized ethylene manufacturing is employed for each of the three pathways. Based on the detailed mass and energy balances and life cycle inventory results, we conduct techno-economic and life cycle analyses to systematically compare the economic and environmental performances of the three pathways. The results indicate that the shale gas-based pathway is the most attractive due to the lowest breakeven ethylene prices; however, it leads to the highest greenhouse gas emissions. On the contrary, the corn stover-based pathway results in the lowest greenhouse gas emissions but the highest breakeven ethylene prices.
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global optimization for sustainable design and synthesis of algae Processing Network for co2 mitigation and biofuel production using life cycle optimization
Aiche Journal, 2014Co-Authors: Jian Gong, Fengqi YouAbstract:Global optimization for sustainable design and synthesis of a large-scale algae Processing Network under economic and environmental criteria is addressed. An algae Processing Network superstructure including 7800 Processing routes is proposed. Based on the superstructure, a multiobjective mixed-integer nonlinear programming (MINLP) model is developed to simultaneously optimize the unit cost and the unit global warming potential (GWP). To efficiently solve the nonconvex MINLP model with separable concave terms and mixed-integer fractional terms in the objective functions, a global optimization strategy that integrates a branch-and-refine algorithm based on successive piecewise linear approximations is proposed and an exact parametric algorithm based on Newton’s method. Two Pareto-optimal curves are obtained for biofuel production and biological carbon sequestration, respectively. The unit annual biofuel production cost ranges from $7.02/gasoline gallon equivalent (GGE) to $9.71/GGE, corresponding to unit GWP’s of 26.491 to 16.52 kg CO2-eq/GGE, respectively. V C 2014 American Institute of Chemical Engineers AIChE J, 60: 3195–3210, 2014
Galia Avidan - One of the best experts on this subject based on the ideXlab platform.
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stimulus dependent dynamic reorganization of the human face Processing Network
Cerebral Cortex, 2016Co-Authors: Gideon Rosenthal, Olaf Sporns, Galia AvidanAbstract:Abstract Using the "face inversion effect", a hallmark of face perception, we examined Network mechanisms supporting face representation by tracking functional magnetic resonance imaging (fMRI) stimulus-dependent dynamic functional connectivity within and between brain Networks associated with the Processing of upright and inverted faces. We developed a novel approach adapting the general linear model (GLM) framework classically used for univariate fMRI analysis to capture stimulus-dependent fMRI dynamic connectivity of the face Network. We show that under the face inversion manipulation, the face and non-face Networks have complementary roles that are evident in their stimulus-dependent dynamic connectivity patterns as assessed by Network decomposition into components or communities. Moreover, we show that connectivity patterns are associated with the behavioral face inversion effect. Thus, we establish "a Network-level signature" of the face inversion effect and demonstrate how a simple physical transformation of the face stimulus induces a dramatic functional reorganization across related brain Networks. Finally, we suggest that the dynamic GLM Network analysis approach, developed here for the face Network, provides a general framework for modeling the dynamics of blocked stimulus-dependent connectivity experimental designs and hence can be applied to a host of neuroimaging studies.
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selective dissociation between core and extended regions of the face Processing Network in congenital prosopagnosia
Cerebral Cortex, 2014Co-Authors: Galia Avidan, Leslie G. Ungerleider, Michal Tanzer, Fadila Hadjbouziane, Ning Liu, Marlene BehrmannAbstract:There is growing consensus that accurate and efficient face recognition is mediated by a neural circuit composed of a posterior “core” and an anterior “extended” set of regions. Here, we characterize the distributed face Network in human individuals with congenital prosopagnosia (CP)—a lifelong impairment in face Processing—relative to that of matched controls. Using functional magnetic resonance imaging, we first uncover largely normal activation patterns in the posterior core face patches in CP. We also document normal activity of the amygdala (emotion Processing) as well as normal or even enhanced functional connectivity between the amygdala and the core regions. Critically, in the same individuals, activation of the anterior temporal cortex (identity Processing) is reduced and connectivity between this region and the posterior core regions is disrupted. The dissociation between the neural profiles of the anterior temporal lobe and amygdala was evident both during a task-related face scan and during a resting state scan, in the absence of visual stimulation. Taken together, these findings elucidate selective disruptions in neural circuitry in CP and offer an explanation for the known differential difficulty in identity versus emotional expression recognition in many individuals with CP.
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functional mri reveals compromised neural integrity of the face Processing Network in congenital prosopagnosia
Current Biology, 2009Co-Authors: Galia Avidan, Marlene BehrmannAbstract:Summary The summed activity of multiple nodes of a distributed cortical Network supports face recognition in humans, including "core" ventral occipitotemporal cortex (VOTC) regions [1–3], and "extended" regions outside VOTC [4, 5]. Many individuals with congenital prosopagnosia—an impairment in face Processing [6–9]—exhibit normal blood oxygenation level-dependent (BOLD) activation in the core VOTC regions [10, 11]. These individuals evince a reduction in the structural integrity of the white matter tracts connecting VOTC to anterior temporal and frontal cortices [12], part of the "extended" face Network. The impairment in congenital prosopagnosia may arise, therefore, not from a dysfunction of the core VOTC areas but from a failure to propagate signals between the intact VOTC and the extended nodes of the Network. Using the fMR adaptation paradigm with famous and unknown faces, we show that individuals with congenital prosopagnosia evince normal adaptation effects in VOTC, indicating sensitivity to facial identity, but show no differential activation for familiar versus unknown faces outside VOTC, particularly in the precuneus/posterior cingulate cortex and the anterior paracingulate cortex. Normal BOLD activation in VOTC is thus insufficient to subserve intact face recognition, and disrupted information propagation between VOTC and the extended face Processing Network may explain the functional impairment in congenital prosopagnosia.
Marlene Behrmann - One of the best experts on this subject based on the ideXlab platform.
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selective dissociation between core and extended regions of the face Processing Network in congenital prosopagnosia
Cerebral Cortex, 2014Co-Authors: Galia Avidan, Leslie G. Ungerleider, Michal Tanzer, Fadila Hadjbouziane, Ning Liu, Marlene BehrmannAbstract:There is growing consensus that accurate and efficient face recognition is mediated by a neural circuit composed of a posterior “core” and an anterior “extended” set of regions. Here, we characterize the distributed face Network in human individuals with congenital prosopagnosia (CP)—a lifelong impairment in face Processing—relative to that of matched controls. Using functional magnetic resonance imaging, we first uncover largely normal activation patterns in the posterior core face patches in CP. We also document normal activity of the amygdala (emotion Processing) as well as normal or even enhanced functional connectivity between the amygdala and the core regions. Critically, in the same individuals, activation of the anterior temporal cortex (identity Processing) is reduced and connectivity between this region and the posterior core regions is disrupted. The dissociation between the neural profiles of the anterior temporal lobe and amygdala was evident both during a task-related face scan and during a resting state scan, in the absence of visual stimulation. Taken together, these findings elucidate selective disruptions in neural circuitry in CP and offer an explanation for the known differential difficulty in identity versus emotional expression recognition in many individuals with CP.
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facing changes and changing faces in adolescence a new model for investigating adolescent specific interactions between pubertal brain and behavioral development
Developmental Cognitive Neuroscience, 2012Co-Authors: Marlene Behrmann, Suzanne K Scherf, Ronald E DahlAbstract:Abstract Adolescence is a time of dramatic physical, cognitive, emotional, and social changes as well as a time for the development of many social–emotional problems. These characteristics raise compelling questions about accompanying neural changes that are unique to this period of development. Here, we propose that studying adolescent-specific changes in face Processing and its underlying neural circuitry provides an ideal model for addressing these questions. We also use this model to formulate new hypotheses. Specifically, pubertal hormones are likely to increase motivation to master new peer-oriented developmental tasks, which will in turn, instigate the emergence of new social/affective components of face Processing. We also predict that pubertal hormones have a fundamental impact on the re-organization of neural circuitry supporting face Processing and propose, in particular, that, the functional connectivity, or temporal synchrony, between regions of the face-Processing Network will change with the emergence of these new components of face Processing in adolescence. Finally, we show how this approach will help reveal why adolescence may be a period of vulnerability in brain development and suggest how it could lead to prevention and intervention strategies that facilitate more adaptive functional interactions between regions within the broader social information Processing Network.
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functional mri reveals compromised neural integrity of the face Processing Network in congenital prosopagnosia
Current Biology, 2009Co-Authors: Galia Avidan, Marlene BehrmannAbstract:Summary The summed activity of multiple nodes of a distributed cortical Network supports face recognition in humans, including "core" ventral occipitotemporal cortex (VOTC) regions [1–3], and "extended" regions outside VOTC [4, 5]. Many individuals with congenital prosopagnosia—an impairment in face Processing [6–9]—exhibit normal blood oxygenation level-dependent (BOLD) activation in the core VOTC regions [10, 11]. These individuals evince a reduction in the structural integrity of the white matter tracts connecting VOTC to anterior temporal and frontal cortices [12], part of the "extended" face Network. The impairment in congenital prosopagnosia may arise, therefore, not from a dysfunction of the core VOTC areas but from a failure to propagate signals between the intact VOTC and the extended nodes of the Network. Using the fMR adaptation paradigm with famous and unknown faces, we show that individuals with congenital prosopagnosia evince normal adaptation effects in VOTC, indicating sensitivity to facial identity, but show no differential activation for familiar versus unknown faces outside VOTC, particularly in the precuneus/posterior cingulate cortex and the anterior paracingulate cortex. Normal BOLD activation in VOTC is thus insufficient to subserve intact face recognition, and disrupted information propagation between VOTC and the extended face Processing Network may explain the functional impairment in congenital prosopagnosia.
Giuseppe Iaria - One of the best experts on this subject based on the ideXlab platform.
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Perceptual and anatomic patterns of selective deficits in facial identity and expression Processing
Neuropsychologia, 2011Co-Authors: Christopher J Fox, Giuseppe Iaria, Hashim M Hanif, Bradley Duchaine, Jason J S BartonAbstract:Whether a single perceptual process or separate and possibly independent processes support facial identity and expression recognition is unclear. We used a morphed-face discrimination test to examine sensitivity to facial expression and identity information in patients with occipital or temporal lobe damage, and structural and functional MRI to correlate behavioral deficits with damage to the core regions of the face-Processing Network. We found selective impairments of identity perception in two patients with right inferotemporal lesions and two prosopagnosic patients with damage limited to the anterior temporal lobes. Of these four patients one exhibited damage to the right fusiform and occipital face areas, while the remaining three showed sparing of these regions. Thus impaired identity perception can occur with damage not only to the fusiform and occipital face areas, but also to other medial occipitotemporal structures that likely form part of a face recognition Network. Impaired expression perception was seen in the fifth patient with damage affecting the face-related portion of the posterior superior temporal sulcus. This subject also had difficulty in discriminating identity when irrelevant variations in expression needed to be discounted. These neuropsychological and neuroimaging data provide evidence to complement models which address the separation of expression and identity perception within the face-Processing Network.
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defining the face Processing Network optimization of the functional localizer in fmri
Human Brain Mapping, 2009Co-Authors: Christopher J Fox, Giuseppe Iaria, Jason J S BartonAbstract:Functional localizers that contrast brain signal when viewing faces versus objects are commonly used in functional magnetic resonance imaging studies of face Processing. However, current protocols do not reliably show all regions of the core system for face Processing in all subjects when conservative statistical thresholds are used, which is problematic in the study of single subjects. Furthermore, arbitrary variations in the applied thresholds are associated with inconsistent estimates of the size of face-selective regions-of-interest (ROIs). We hypothesized that the use of more natural dynamic facial images in localizers might increase the likelihood of identifying face-selective ROIs in individual subjects, and we also investigated the use of a method to derive the statistically optimal ROI cluster size independent of thresholds. We found that dynamic facial stimuli were more effective than static stimuli, identifying 98% (versus 72% for static) of ROIs in the core face Processing system and 69% (versus 39% for static) of ROIs in the extended face Processing system. We then determined for each core face Processing ROI, the cluster size associated with maximum statistical face-selectivity, which on average was approximately 50 mm(3) for the fusiform face area, the occipital face area, and the posterior superior temporal sulcus. We suggest that the combination of (a) more robust face-related activity induced by a dynamic face localizer and (b) a cluster-size determination based on maximum face-selectivity increases both the sensitivity and the specificity of the characterization of face-related ROIs in individual subjects.
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the correlates of subjective perception of identity and expression in the face Network an fmri adaptation study
NeuroImage, 2009Co-Authors: So Young Moon, Giuseppe Iaria, Jason J S BartonAbstract:The recognition of facial identity and expression are distinct tasks, with current models hypothesizing anatomic segregation of Processing within a face-Processing Network. Using fMRI adaptation and a region-of-interest approach, we assessed how the perception of identity and expression changes in morphed stimuli affected the signal within this Network, by contrasting (a) changes that crossed categorical boundaries of identity or expression with those that did not, and (b) changes that subjects perceived as causing identity or expression to change, versus changes that they perceived as not affecting the category of identity or expression. The occipital face area (OFA) was sensitive to any structural change in a face, whether it was identity or expression, but its signal did not correlate with whether subjects perceived a change or not. Both the fusiform face area (FFA) and the posterior superior temporal sulcus (pSTS) showed release from adaptation when subjects perceived a change in either identity or expression, although in the pSTS this effect only occurred when subjects were explicitly attending to expression. The middle superior temporal sulcus (mSTS) showed release from adaptation for expression only, and the precuneus for identity only. The data support models where the OFA is involved in the early perception of facial structure. However, evidence for a functional overlap in the FFA and pSTS, with both identity and expression signals in both areas, argues against a complete independence of identity and expression Processing in these regions of the core face-Processing Network.
-
disconnection in prosopagnosia and face Processing
Cortex, 2008Co-Authors: Giuseppe Iaria, Jason J S BartonAbstract:Face perception is a function with significant complexity, reflected in cognitive models that propose a hierarchy of parallel and serial Processing stages. Current neuroimaging data also show that face perception involves a core Processing Network of cortical modules, which are likely specialized for different functions involved in face Processing. The core face Processing Network is further linked to an extended face Processing Network which is not solely involved in the perception of faces, but rather contains modules mediating the Processing of semantic, biographic and emotional information about people. The segregation of these processes within discrete anatomic regions creates the potential for disconnection between regions to generate neuropsychological deficits involving faces. In this review we consider the types of disconnection possible both within the core face Processing system and between the core and extended systems, the pattern of deficits that would be considered as evidence of such disconnections, the potential anatomy of lesions that would create them, and whether any cases exist that meet these criteria.
