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Granovetter MC, Maallo AMS, Ling S, Robert S, Freud E, Patterson C, Behrmann M. Functional Resilience of the Neural Visual Recognition System Post-Pediatric Occipitotemporal Resection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.08.592792. [PMID: 38766137 PMCID: PMC11100714 DOI: 10.1101/2024.05.08.592792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
In the typically developing (TD) brain, neural representations for visual stimulus categories (e.g., faces, objects, and words) emerge in bilateral occipitotemporal cortex (OTC), albeit with weighted asymmetry; in parallel, recognition behavior continues to be refined. A fundamental question is whether two hemispheres are necessary or redundant for the emergence of neural representations and recognition behavior typically distributed across both hemispheres. The rare population of patients undergoing unilateral OTC resection in childhood offers a unique opportunity to evaluate whether neural computations for visual stimulus individuation suffice for recognition with only a single developing OTC. Here, using functional magnetic resonance imaging, we mapped category selectivity (CS) and neural representations for individual stimulus exemplars using repetition suppression (RS) in the non-resected hemisphere of pediatric OTC resection patients (n = 9) and control patients with resection outside of OTC (n = 12), as well as in both hemispheres of TD controls (n = 21). There were no univariate group differences in the magnitude of CS or RS or any multivariate differences (per representational similarity analysis) in neural activation to faces, objects, or words across groups. Notwithstanding their comparable neural profiles, accuracy of OTC resection patients on face and object recognition, but not word recognition, was statistically inferior to that of controls. The comparable neural signature of the OTC resection patients' preserved hemisphere and the other two groups highlights the resilience of the system following damage to the contralateral homologue. Critically, however, a single OTC does not suffice for normal behavior, and, thereby, implicates the necessity for two hemispheres.
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Affiliation(s)
- Michael C. Granovetter
- School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Psychology and Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Anne Margarette S. Maallo
- Department of Psychology and Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Shouyu Ling
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Sophia Robert
- Department of Psychology and Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Erez Freud
- Department of Psychology, York University, Toronto, ON, CA
| | | | - Marlene Behrmann
- Department of Psychology and Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
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Burns EJ, Gaunt E, Kidane B, Hunter L, Pulford J. A new approach to diagnosing and researching developmental prosopagnosia: Excluded cases are impaired too. Behav Res Methods 2023; 55:4291-4314. [PMID: 36459376 PMCID: PMC9718472 DOI: 10.3758/s13428-022-02017-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2022] [Indexed: 12/04/2022]
Abstract
Developmental prosopagnosia is characterized by severe, lifelong difficulties when recognizing facial identity. Unfortunately, the most common diagnostic assessment (Cambridge Face Memory Test) misses 50-65% of individuals who believe that they have this condition. This results in such excluded cases' absence from scientific knowledge, effect sizes of impairment potentially overestimated, treatment efficacy underrated, and may elicit in them a negative experience of research. To estimate their symptomology and group-level impairments in face processing, we recruited a large cohort who believes that they have prosopagnosia. Matching prior reports, 56% did not meet criteria on the Cambridge Face Memory Test. However, the severity of their prosopagnosia symptoms and holistic perception deficits were comparable to those who did meet criteria. Excluded cases also exhibited face perception and memory impairments that were roughly one standard deviation below neurotypical norms, indicating the presence of objective problems. As the prosopagnosia index correctly classified virtually every case, we propose it should be the primary method for providing a diagnosis, prior to subtype categorization. We present researchers with a plan on how they can analyze these excluded prosopagnosia cases in their future work without negatively impacting their traditional findings. We anticipate such inclusion will enhance scientific knowledge, more accurately estimate effect sizes of impairments and treatments, and identify commonalities and distinctions between these different forms of prosopagnosia. Owing to their atypicalities in visual perception, we recommend that the prosopagnosia index should be used to screen out potential prosopagnosia cases from broader vision research.
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Affiliation(s)
- Edwin J Burns
- Department of Psychology, Edge Hill University, Ormskirk, UK.
| | - Elizabeth Gaunt
- Department of Psychology, Edge Hill University, Ormskirk, UK
| | - Betiel Kidane
- Department of Psychology, Edge Hill University, Ormskirk, UK
| | - Lucy Hunter
- Department of Psychology, Edge Hill University, Ormskirk, UK
| | - Jaylea Pulford
- Department of Psychology, Edge Hill University, Ormskirk, UK
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Bell L, Duchaine B, Susilo T. Dissociations between face identity and face expression processing in developmental prosopagnosia. Cognition 2023; 238:105469. [PMID: 37216847 DOI: 10.1016/j.cognition.2023.105469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 05/24/2023]
Abstract
Individuals with developmental prosopagnosia (DPs) experience severe and lifelong deficits recognising faces, but whether their deficits are selective to the processing of face identity or extend to the processing of face expression remains unclear. Clarifying this issue is important for understanding DP impairments and advancing theories of face processing. We compared identity and expression processing in a large sample of DPs (N = 124) using three different matching tasks that each assessed identity and expression processing with identical experimental formats. We ran each task in upright and inverted orientations and we measured inversion effects to assess the integrity of upright-specific face processes. We report three main results. First, DPs showed large deficits at discriminating identity but only subtle deficits at discriminating expression. Second, DPs showed a reduced inversion effect for identity but a normal inversion effect for expression. Third, DPs' performance on the expression tasks were linked to autism traits, but their performance on the identity tasks were not. These results constitute several dissociations between identity and expression processing in DP, and they are consistent with the view that the core impairment in DP is highly selective to identity.
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Affiliation(s)
- Lauren Bell
- Victoria University of Wellington, New Zealand
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Ayzenberg V, Granovetter MC, Robert S, Patterson C, Behrmann M. Differential functional reorganization of ventral and dorsal visual pathways following childhood hemispherectomy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.03.551494. [PMID: 37577633 PMCID: PMC10418255 DOI: 10.1101/2023.08.03.551494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Hemispherectomy is a surgical procedure in which an entire hemisphere of a patient's brain is resected or functionally disconnected to manage seizures in individuals with drug-resistant epilepsy. Despite the extensive loss of input from both ventral and dorsal visual pathways of one hemisphere, pediatric patients who have undergone hemispherectomy show a remarkably high degree of perceptual function across many domains. In the current study, we sought to understand the extent to which functions of the ventral and dorsal visual pathways reorganize to the contralateral hemisphere following childhood hemispherectomy. To this end, we collected fMRI data from an equal number of left and right hemispherectomy patients who completed tasks that typically elicit lateralized responses from the ventral or the dorsal pathway, namely, word (left ventral), face (right ventral), tool (left dorsal), and global form (right dorsal) perception. Overall, there was greater evidence of functional reorganization in the ventral pathway than in the dorsal pathway. Importantly, because ventral and dorsal reorganization was tested in the very same patients, these results cannot be explained by idiosyncratic factors such as disease etiology, age at the time of surgery, or age at testing. These findings suggest that because the dorsal pathway may mature earlier, it may have a shorter developmental window of plasticity than the ventral pathway and, hence, be less malleable.
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Affiliation(s)
- Vladislav Ayzenberg
- Department of Psychology, University of Pennsylvania
- Department of Psychology and Neuroscience Institute, Carnegie Mellon University
| | - Michael C Granovetter
- Department of Psychology and Neuroscience Institute, Carnegie Mellon University
- School of Medicine, University of Pittsburgh
| | - Sophia Robert
- Department of Psychology and Neuroscience Institute, Carnegie Mellon University
| | - Christina Patterson
- School of Medicine, University of Pittsburgh
- Department of Pediatrics, University of Pittsburgh
| | - Marlene Behrmann
- Department of Psychology and Neuroscience Institute, Carnegie Mellon University
- Department of Pediatrics, University of Pittsburgh
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With childhood hemispherectomy, one hemisphere can support—but is suboptimal for—word and face recognition. Proc Natl Acad Sci U S A 2022; 119:e2212936119. [PMID: 36282918 PMCID: PMC9636967 DOI: 10.1073/pnas.2212936119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The right and left cerebral hemispheres are important for face and word recognition, respectively—a specialization that emerges over human development. The question is whether this bilateral distribution is necessary or whether a single hemisphere, be it left or right, can support both face and word recognition. Here, face and word recognition accuracy in patients (median age 16.7 y) with a single hemisphere following childhood hemispherectomy was compared against matched typical controls. In experiment 1, participants viewed stimuli in central vision. Across both face and word tasks, accuracy of both left and right hemispherectomy patients, while significantly lower than controls' accuracy, averaged above 80% and did not differ from each other. To compare patients' single hemisphere more directly to one hemisphere of controls, in experiment 2, participants viewed stimuli in one visual field to constrain initial processing chiefly to a single (contralateral) hemisphere. Whereas controls had higher word accuracy when words were presented to the right than to the left visual field, there was no field/hemispheric difference for faces. In contrast, left and right hemispherectomy patients, again, showed comparable performance to one another on both face and word recognition, albeit significantly lower than controls. Altogether, the findings indicate that a single developing hemisphere, either left or right, may be sufficiently plastic for comparable representation of faces and words. However, perhaps due to increased competition or “neural crowding,” constraining cortical representations to one hemisphere may collectively hamper face and word recognition, relative to that observed in typical development with two hemispheres.
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Haeger A, Pouzat C, Luecken V, N’Diaye K, Elger C, Kennerknecht I, Axmacher N, Dinkelacker V. Face Processing in Developmental Prosopagnosia: Altered Neural Representations in the Fusiform Face Area. Front Behav Neurosci 2021; 15:744466. [PMID: 34867227 PMCID: PMC8636799 DOI: 10.3389/fnbeh.2021.744466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/20/2021] [Indexed: 11/13/2022] Open
Abstract
Rationale: Face expertise is a pivotal social skill. Developmental prosopagnosia (DP), i.e., the inability to recognize faces without a history of brain damage, affects about 2% of the general population, and is a renowned model system of the face-processing network. Within this network, the right Fusiform Face Area (FFA), is particularly involved in face identity processing and may therefore be a key element in DP. Neural representations within the FFA have been examined with Representational Similarity Analysis (RSA), a data-analytical framework in which multi-unit measures of brain activity are assessed with correlation analysis. Objectives: Our study intended to scrutinize modifications of FFA-activation during face encoding and maintenance based on RSA. Methods: Thirteen participants with DP (23-70 years) and 12 healthy control subjects (19-62 years) participated in a functional MRI study, including morphological MRI, a functional FFA-localizer and a modified Sternberg paradigm probing face memory encoding and maintenance. Memory maintenance of one, two, or four faces represented low, medium, and high memory load. We examined conventional activation differences in response to working memory load and applied RSA to compute individual correlation-matrices on the voxel level. Group correlation-matrices were compared via Donsker's random walk analysis. Results: On the functional level, increased memory load entailed both a higher absolute FFA-activation level and a higher degree of correlation between activated voxels. Both aspects were deficient in DP. Interestingly, control participants showed a homogeneous degree of correlation for successful trials during the experiment. In DP-participants, correlation levels between FFA-voxels were significantly lower and were less sustained during the experiment. In behavioral terms, DP-participants performed poorer and had longer reaction times in relation to DP-severity. Furthermore, correlation levels were negatively correlated with reaction times for the most demanding high load condition. Conclusion: We suggest that participants with DP fail to generate robust and maintained neural representations in the FFA during face encoding and maintenance, in line with poorer task performance and prolonged reaction times. In DP, alterations of neural coding in the FFA might therefore explain curtailing in working memory and contribute to impaired long-term memory and mental imagery.
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Affiliation(s)
- Alexa Haeger
- JARA-BRAIN, Jülich, Germany
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine (INM-11), Jülich, Germany
- Department of Neurology, RWTH Aachen University, Aachen, Germany
| | | | | | - Karim N’Diaye
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, Paris, France
| | | | - Ingo Kennerknecht
- Institute of Human Genetics, Westfaelische Wilhelms-Universitaet Muenster, Muenster, Germany
| | - Nikolai Axmacher
- Department of Neuropsychology, Ruhr University Bochum, Bochum, Germany
| | - Vera Dinkelacker
- Neurology Department, Hautepierre Hospital, University of Strasbourg, Strasbourg, France
- Rothschild Foundation, Neurology Department, Paris, France
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Takahashi Y, Murata S, Idei H, Tomita H, Yamashita Y. Neural network modeling of altered facial expression recognition in autism spectrum disorders based on predictive processing framework. Sci Rep 2021; 11:14684. [PMID: 34312400 PMCID: PMC8313712 DOI: 10.1038/s41598-021-94067-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 07/06/2021] [Indexed: 11/20/2022] Open
Abstract
The mechanism underlying the emergence of emotional categories from visual facial expression information during the developmental process is largely unknown. Therefore, this study proposes a system-level explanation for understanding the facial emotion recognition process and its alteration in autism spectrum disorder (ASD) from the perspective of predictive processing theory. Predictive processing for facial emotion recognition was implemented as a hierarchical recurrent neural network (RNN). The RNNs were trained to predict the dynamic changes of facial expression movies for six basic emotions without explicit emotion labels as a developmental learning process, and were evaluated by the performance of recognizing unseen facial expressions for the test phase. In addition, the causal relationship between the network characteristics assumed in ASD and ASD-like cognition was investigated. After the developmental learning process, emotional clusters emerged in the natural course of self-organization in higher-level neurons, even though emotional labels were not explicitly instructed. In addition, the network successfully recognized unseen test facial sequences by adjusting higher-level activity through the process of minimizing precision-weighted prediction error. In contrast, the network simulating altered intrinsic neural excitability demonstrated reduced generalization capability and impaired emotional clustering in higher-level neurons. Consistent with previous findings from human behavioral studies, an excessive precision estimation of noisy details underlies this ASD-like cognition. These results support the idea that impaired facial emotion recognition in ASD can be explained by altered predictive processing, and provide possible insight for investigating the neurophysiological basis of affective contact.
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Affiliation(s)
- Yuta Takahashi
- Department of Psychiatry, Tohoku University Hospital, Sendai, Japan
- Department of Information Medicine, National Center of Neurology and Psychiatry, 4-1-1 Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan
| | - Shingo Murata
- Department of Electronics and Electrical Engineering, Faculty of Science and Technology, Keio University, Tokyo, Japan
| | - Hayato Idei
- Department of Intermedia Studies, Waseda University, Tokyo, Japan
| | - Hiroaki Tomita
- Department of Psychiatry, Tohoku University Hospital, Sendai, Japan
| | - Yuichi Yamashita
- Department of Information Medicine, National Center of Neurology and Psychiatry, 4-1-1 Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan.
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8
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Seitz RJ. Beliefs: A challenge in neuropsychological disorders. J Neuropsychol 2021; 16:21-37. [PMID: 33969626 DOI: 10.1111/jnp.12249] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 03/11/2021] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Beliefs have recently been defined as the neural product of perception of objects and events in the external world and of an affirmative internal affective state reflecting personal meaning. It is, however, undetermined in which way diseases of the brain affect these integrative processes. METHODS Here, the formation and updating of abnormal beliefs in cerebral disorders are described. RESULTS It will be shown that well-defined neuropsychological syndromes resulting from brain lesions also interfere with the neural processes that enable the formation, up-dating and communication of beliefs. Similarly, in neuropsychiatric disorders abnormal and delusional beliefs appear to be caused by altered perception and/or misattribution of aversive meaning. CONCLUSION Given the importance of beliefs for ordinary social behaviour, abnormal beliefs are a challenge in neuropsychological disorders.
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Affiliation(s)
- Rüdiger J Seitz
- Department of Neurology, Centre of Neurology and Neuropsychiatry, LVR-Klinikum Düsseldorf, Medical Faculty, Heinrich-Heine-University Düsseldorf, Germany.,Florey Neuroscience Institutes, Melbourne, Victoria, Australia
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Abstract
Alexia refers to a reading disorder caused by some form of acquired brain pathology, most commonly a stroke or tumor, in a previously literate subject. In neuropsychology, a distinction is made between central alexia (commonly seen in aphasia) and peripheral alexia (a perceptual or attentional deficit). The prototypical peripheral alexia is alexia without agraphia (pure alexia), where patients can write but are impaired in reading words and letters. Pure alexia is associated with damage to the left ventral occipitotemporal cortex (vOT) or its connections. Hemianopic alexia is associated with less extensive occipital damage and is caused by a visual field defect, which creates problems reading longer words and passages of text. Reading impairment can also arise due to attentional deficits, most commonly following right hemisphere or bilateral lesions. Studying patients with alexia, along with functional imaging studies of normal readers, has improved our understanding of the neurobiological processes involved in reading. A key question is whether an area in the left ventral occipitotemporal cortex is specialized for or selectively involved in word processing, or whether reading relies on tuning of more general purpose perceptual areas. Reading deficits may also be observed in dementia and traumatic brain injury, but often with less consistent deficit patterns than in patients with focal lesions.
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Affiliation(s)
- Randi Starrfelt
- Department of Psychology, University of Copenhagen, Copenhagen, Denmark.
| | - Zoe Woodhead
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
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Yuan Y, Huang F, Gao ZH, Cai WC, Xiao JX, Yang YE, Zhu PL. Delayed diagnosis of prosopagnosia following a hemorrhagic stroke in an elderly man: A case report. World J Clin Cases 2020; 8:6487-6498. [PMID: 33392335 PMCID: PMC7760442 DOI: 10.12998/wjcc.v8.i24.6487] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 10/09/2020] [Accepted: 10/26/2020] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Acquired prosopagnosia is a rare condition characterized by the loss of familiarity with previously known faces and the inability to recognize new ones. It usually occurs after the onset of brain lesions such as in a stroke. The initial identification of prosopagnosia generally relies on a patient’s self-report, which can be challenging if it lacks an associated chief complaint. There were few cases of prosopagnosia presenting purely as eye symptoms in the previous literature confirmed by functional magnetic resonance imaging (MRI).
CASE SUMMARY We present a case of delayed diagnosis of prosopagnosia after a right hemisphere stroke in an elderly man whose chief complaint was persistent and progressive "blurred vision" without facial recognition impairment. Ophthalmic tests revealed a homonymous left upper quadrantanopia, with normal visual acuity. He was found by accident to barely recognize familiar faces. The patient showed severe deficit in face recognition and perception tests, and mild memory loss in neuropsychological assessments. Further functional MRI revealed the visual recognition deficits were face-specific. After behavioral intervention, the patient started to rely on other cues to compensate for poor facial recognition. His prosopagnosia showed no obvious improvement eight months after the stroke, which had negative impact on his social network.
CONCLUSION Our case demonstrates that the presentation of prosopagnosia can be atypical, and visual difficulties might be a clinical manifestation solely of prosopagnosia, which emphasizes the importance of routinely considering face recognition impairment among elderly patients with brain lesions.
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Affiliation(s)
- Yin Yuan
- Department of Geriatric Medicine, Fujian Provincial Hospital, Fuzhou 350001, Fujian Province, China
- Shengli Clinical Medical College, Fujian Medical University , Fuzhou 350100, Fujian Province, China
- Fujian Provincial Institute of Clinical Geriatrics, Fuzhou 350001, Fujian Province, China
- Fujian Provincial Key Laboratory of Geriatrics, Fuzhou 350001, Fujian Province, China
- Fujian Provincial Center for Geriatrics, Fuzhou 350001, Fujian Province, China
| | - Feng Huang
- Department of Geriatric Medicine, Fujian Provincial Hospital, Fuzhou 350001, Fujian Province, China
- Shengli Clinical Medical College, Fujian Medical University , Fuzhou 350100, Fujian Province, China
- Fujian Provincial Institute of Clinical Geriatrics, Fuzhou 350001, Fujian Province, China
- Fujian Provincial Key Laboratory of Geriatrics, Fuzhou 350001, Fujian Province, China
- Fujian Provincial Center for Geriatrics, Fuzhou 350001, Fujian Province, China
| | - Zhong-Hai Gao
- Department of Ophthalmology, Fujian Provincial Hospital, Fuzhou 350001, Fujian Province, China
| | - Wen-Chao Cai
- Department of Radiology, Fujian Provincial Hospital, Fuzhou 350001, Fujian Province, China
| | - Jia-Xin Xiao
- Department of Geriatric Medicine, Fujian Provincial Hospital, Fuzhou 350001, Fujian Province, China
- Shengli Clinical Medical College, Fujian Medical University , Fuzhou 350100, Fujian Province, China
- Fujian Provincial Institute of Clinical Geriatrics, Fuzhou 350001, Fujian Province, China
- Fujian Provincial Key Laboratory of Geriatrics, Fuzhou 350001, Fujian Province, China
- Fujian Provincial Center for Geriatrics, Fuzhou 350001, Fujian Province, China
| | - Yue-Er Yang
- Department of Geriatric Medicine, Fujian Provincial Hospital, Fuzhou 350001, Fujian Province, China
- Shengli Clinical Medical College, Fujian Medical University , Fuzhou 350100, Fujian Province, China
- Fujian Provincial Institute of Clinical Geriatrics, Fuzhou 350001, Fujian Province, China
- Fujian Provincial Key Laboratory of Geriatrics, Fuzhou 350001, Fujian Province, China
- Fujian Provincial Center for Geriatrics, Fuzhou 350001, Fujian Province, China
| | - Peng-Li Zhu
- Department of Geriatric Medicine, Fujian Provincial Hospital, Fuzhou 350001, Fujian Province, China
- Shengli Clinical Medical College, Fujian Medical University , Fuzhou 350100, Fujian Province, China
- Fujian Provincial Institute of Clinical Geriatrics, Fuzhou 350001, Fujian Province, China
- Fujian Provincial Key Laboratory of Geriatrics, Fuzhou 350001, Fujian Province, China
- Fujian Provincial Center for Geriatrics, Fuzhou 350001, Fujian Province, China
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Mirrored brain organization: Statistical anomaly or reversal of hemispheric functional segregation bias? Proc Natl Acad Sci U S A 2020; 117:14057-14065. [PMID: 32513702 DOI: 10.1073/pnas.2002981117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Humans demonstrate a prototypical hemispheric functional segregation pattern, with language and praxis lateralizing to the left hemisphere and spatial attention, face recognition, and emotional prosody to the right hemisphere. In this study, we used fMRI to determine laterality for all five functions in each participant. Crucially, we recruited a sample of left-handers preselected for atypical (right) language dominance (n = 24), which allowed us to characterize hemispheric asymmetry of the other functions and compare their functional segregation pattern with that of left-handers showing typical language dominance (n = 39). Our results revealed that most participants with left language dominance display the prototypical pattern of functional hemispheric segregation (44%) or deviate from this pattern in only one function (35%). Similarly, the vast majority of right language dominant participants demonstrated a completely mirrored brain organization (50%) or a reversal for all but one cognitive function (32%). Participants deviating by more than one function from the standard segregation pattern showed poorer cognitive performance, in line with an oft-presumed biological advantage of hemispheric functional segregation.
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