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Bleau M, Paré S, Chebat DR, Kupers R, Nemargut JP, Ptito M. Neural substrates of spatial processing and navigation in blindness: An activation likelihood estimation meta-analysis. Front Neurosci 2022; 16:1010354. [PMID: 36340755 PMCID: PMC9630591 DOI: 10.3389/fnins.2022.1010354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 09/30/2022] [Indexed: 12/02/2022] Open
Abstract
Even though vision is considered the best suited sensory modality to acquire spatial information, blind individuals can form spatial representations to navigate and orient themselves efficiently in space. Consequently, many studies support the amodality hypothesis of spatial representations since sensory modalities other than vision contribute to the formation of spatial representations, independently of visual experience and imagery. However, given the high variability in abilities and deficits observed in blind populations, a clear consensus about the neural representations of space has yet to be established. To this end, we performed a meta-analysis of the literature on the neural correlates of spatial processing and navigation via sensory modalities other than vision, like touch and audition, in individuals with early and late onset blindness. An activation likelihood estimation (ALE) analysis of the neuroimaging literature revealed that early blind individuals and sighted controls activate the same neural networks in the processing of non-visual spatial information and navigation, including the posterior parietal cortex, frontal eye fields, insula, and the hippocampal complex. Furthermore, blind individuals also recruit primary and associative occipital areas involved in visuo-spatial processing via cross-modal plasticity mechanisms. The scarcity of studies involving late blind individuals did not allow us to establish a clear consensus about the neural substrates of spatial representations in this specific population. In conclusion, the results of our analysis on neuroimaging studies involving early blind individuals support the amodality hypothesis of spatial representations.
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Affiliation(s)
- Maxime Bleau
- École d’Optométrie, Université de Montréal, Montreal, QC, Canada
| | - Samuel Paré
- École d’Optométrie, Université de Montréal, Montreal, QC, Canada
| | - Daniel-Robert Chebat
- Visual and Cognitive Neuroscience Laboratory (VCN Lab), Department of Psychology, Faculty of Social Sciences and Humanities, Ariel University, Ariel, Israel
- Navigation and Accessibility Research Center of Ariel University (NARCA), Ariel University, Ariel, Israel
| | - Ron Kupers
- École d’Optométrie, Université de Montréal, Montreal, QC, Canada
- Institute of Neuroscience, Faculty of Medicine, Université de Louvain, Brussels, Belgium
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | | | - Maurice Ptito
- École d’Optométrie, Université de Montréal, Montreal, QC, Canada
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
- *Correspondence: Maurice Ptito,
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Si L, Cui B, Li Z, Li X, Li K, Ling X, Shen B, Yang X. Concurrent brain structural and functional alterations in patients with chronic unilateral vestibulopathy. Quant Imaging Med Surg 2022; 12:3115-3125. [PMID: 35655817 PMCID: PMC9131349 DOI: 10.21037/qims-21-655] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 03/02/2022] [Indexed: 07/20/2023]
Abstract
BACKGROUND Chronic unilateral vestibulopathy (CUVP) is a common chronic vestibular syndrome which may be caused by incomplete vestibular dynamic compensation. Neuroimaging technology provides important clues to explore the mechanism of complicated by vestibular dynamic compensation in patients with CUVP. However, previous studies mostly used positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) to investigate the changes of brain function in these patients during the task state, few studies have investigated the alterations during the resting state, Therefore, the study aimed to investigate the possible brain structural and functional alterations in patients with CUVP and explore the dynamic compensation state in patients with CUVP. METHODS We recruited 18 patients with right CUVP and 18 age-, gender-, and education level-matched healthy controls (HCs). Vestibular evaluations, such as videonystagmography and caloric tests, were performed. All participants underwent Dizziness Handicap Inventory (DHI) assessment. All participants underwent multimodal magnetic resonance imaging of the brain, including fMRI and three-dimensional T1-weighted MRI. We analyzed the amplitude of low frequency fluctuations (ALFF), regional homogeneity (ReHo), seed based functional connectivity, and voxel-based morphometry (VBM). RESULTS Compared with HCs, CUVP patients showed significantly increased ALFF values in the right supplementary motor area, significantly decreased ALFF values in the right middle occipital gyrus, significantly decreased ReHo values in the bilateral superior parietal lobule, and significantly enhanced ReHo values in the bilateral cerebellar hemisphere [both P<0.05, family-wise error (FWE) corrected]. Compared with HCs, patients with CUVP showed increased gray matter volumes in the left medial superior frontal gyrus and left middle cingulate gyrus [P<0.001, false discovery rate (FDR) corrected]. Compared with HCs, in patients with CUVP, functional connectivity was enhanced between the left medial superior frontal gyrus and the left orbital inferior frontal gyrus and left angular gyrus and was significantly decreased between the left medial superior frontal gyrus and the right dorsolateral superior frontal gyrus (both P<0.01, FWE corrected). Pearson correlation analysis showed that there was a positive correlation between DHI score and VBM value of the left medial superior frontal gyrus in patients with CUVP (r=-0.430, P=0.003). CONCLUSIONS This study identified abnormalities of neuronal activity intensity and overall activity synchronization in multiple brain regions in patients with CUVP, suggesting that patients with CUVP have extensive brain functional abnormalities, which in turn affects their spatial perception and motor perception. Increased gray matter volume and functional connectivity of the default mode network may be used as potential imaging biomarkers of chronic symptoms in patients with CUVP.
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Affiliation(s)
- Lihong Si
- Department of Neurology, Aerospace Center Hospital (Peking University Aerospace School of Clinical Medicine), Beijing, China
| | - Bin Cui
- Department of Neurology, Aerospace Center Hospital (Peking University Aerospace School of Clinical Medicine), Beijing, China
| | - Zheyuan Li
- Department of Neurology, Aerospace Center Hospital (Peking University Aerospace School of Clinical Medicine), Beijing, China
| | - Xiang Li
- The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, China
| | - Kangzhi Li
- Department of Neurology, Aerospace Center Hospital (Peking University Aerospace School of Clinical Medicine), Beijing, China
| | - Xia Ling
- Department of Neurology, Aerospace Center Hospital (Peking University Aerospace School of Clinical Medicine), Beijing, China
| | - Bo Shen
- The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, China
| | - Xu Yang
- Department of Neurology, Aerospace Center Hospital (Peking University Aerospace School of Clinical Medicine), Beijing, China
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Zhao Q, Li J, Xiao Y, Cao H, Wang X, Zhang W, Li S, Liao W, Gong Q, Lui S. Distinct neuroanatomic subtypes in antipsychotic-treated patients with schizophrenia classified by the predefined classification in a never-treated sample. PSYCHORADIOLOGY 2021; 1:212-224. [PMID: 38666223 PMCID: PMC11025559 DOI: 10.1093/psyrad/kkab018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/17/2021] [Accepted: 12/01/2021] [Indexed: 02/05/2023]
Abstract
Background Distinct neuroanatomic subtypes have been identified in never-treated patients with schizophrenia based on cerebral structural abnormalities, but whether antipsychotic-treated patients would be stratified under the guidance of such previously formed classification remains unclear. Objective The present study aimed to investigate alterations of brain structures in antipsychotic-treated patients with schizophrenia based on a predefined morphological classification and their relationships with cognitive performance. Methods Cortical thickness, surface area, and subcortical volume were extracted from 147 antipsychotic-treated patients with schizophrenia using structural magnetic resonance imaging for classification. The Brief Assessment of Cognition in Schizophrenia (BACS) and Positive and Negative Syndrome Scale (PANSS) were used to assess cognition and symptoms. Results Antipsychotic-treated patients were categorized into three subtypes with distinct patterns of brain morphological alterations. Subtypes 1 and 2 were characterized by widespread deficits in cortical thickness but relatively limited deficits in surface area. In contrast, subtype 3 demonstrated cortical thickening mainly in parietal-occipital regions and widespread deficits in surface area. All three subgroups demonstrated cognitive deficits compared with healthy controls. Significant associations between neuroanatomic and cognitive abnormalities were only observed in subtype 1, where cortical thinning in the left lingual gyrus was conversely related to symbol coding performance. Conclusions Similar to drug-naïve patients, neuroanatomic heterogeneity exists in antipsychotic-treated patients, with disparate associations with cognition. These findings promote our understanding of relationships between neuroanatomic abnormalities and cognitive performance in the context of heterogeneity. Moreover, these results suggest that neurobiological heterogeneity needs to be considered in cognitive research in schizophrenia.
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Affiliation(s)
- Qiannan Zhao
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu 610041, China
- Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu 610041, China
- Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Jiao Li
- The Clinical Hospital of Chengdu Brain Science Institute, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China
- MOE Key Lab for Neuroinformation, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Yuan Xiao
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu 610041, China
- Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu 610041, China
- Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Hengyi Cao
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu 610041, China
- Center for Psychiatric Neuroscience, Feinstein Institute for Medical Research, Manhasset, NY 11030, United States
- Division of Psychiatry Research, Zucker Hillside Hospital, Glen Oaks, NY 11004, United States
| | - Xiao Wang
- The Clinical Hospital of Chengdu Brain Science Institute, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China
- MOE Key Lab for Neuroinformation, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Wenjing Zhang
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu 610041, China
- Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu 610041, China
- Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Siyi Li
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu 610041, China
- Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu 610041, China
- Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Wei Liao
- The Clinical Hospital of Chengdu Brain Science Institute, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China
- MOE Key Lab for Neuroinformation, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Qiyong Gong
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu 610041, China
- Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu 610041, China
- Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Su Lui
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu 610041, China
- Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu 610041, China
- Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital of Sichuan University, Chengdu 610041, China
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Palejwala AH, Dadario NB, Young IM, O'Connor K, Briggs RG, Conner AK, O'Donoghue DL, Sughrue ME. Anatomy and White Matter Connections of the Lingual Gyrus and Cuneus. World Neurosurg 2021; 151:e426-e437. [PMID: 33894399 DOI: 10.1016/j.wneu.2021.04.050] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 04/12/2021] [Indexed: 11/16/2022]
Abstract
BACKGROUND The medial occipital lobe, composed of the lingual gyrus and cuneus, is necessary for both basic and higher level visual processing. It is also known to facilitate cross-modal, nonvisual functions, such as linguistic processing and verbal memory, after the loss of the visual senses. A detailed cortical model elucidating the white matter connectivity associated with this area could improve our understanding of the interacting brain networks that underlie complex human processes and postoperative outcomes related to vision and language. METHODS Generalized q-sampling imaging tractography, validated by gross anatomic dissection for qualitative visual agreement, was performed on 10 healthy adult controls obtained from the Human Connectome Project. RESULTS Major white matter connections were identified by tractography and validated by gross dissection, which connected the medial occipital lobe with itself and the adjacent cortices, especially the temporal lobe. The short- and long-range connections identified consisted mainly of U-shaped association fibers, intracuneal fibers, and inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, middle longitudinal fasciculus, and lingual-fusiform connections. CONCLUSIONS The medial occipital lobe is an extremely interconnected system, supporting its ability to perform coordinated basic visual processing, but also serves as a center for many long-range association fibers, supporting its importance in nonvisual functions, such as language and memory. The presented data represent clinically actionable anatomic information that can be used in multimodal navigation of white matter lesions in the medial occipital lobe to prevent neurologic deficits and improve patients' quality of life after cerebral surgery.
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Affiliation(s)
- Ali H Palejwala
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Nicholas B Dadario
- Robert Wood Johnson Medical School, Rutgers University, New Brunswick, New Jersey, USA
| | | | - Kyle O'Connor
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Robert G Briggs
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Andrew K Conner
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Daniel L O'Donoghue
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Michael E Sughrue
- Centre for Minimally Invasive Neurosurgery, Prince of Wales Private Hospital, Sydney, New South Wales, Australia.
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Mao Y, Kanai R, Ding C, Bi T, Qiu J. Temporal variability of brain networks predicts individual differences in bistable perception. Neuropsychologia 2020; 142:107426. [PMID: 32147392 DOI: 10.1016/j.neuropsychologia.2020.107426] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 01/23/2020] [Accepted: 03/02/2020] [Indexed: 11/30/2022]
Abstract
When ambiguous visual stimuli are presented to the eyes, conscious perception can spontaneously alternate across the competing interpretations - which was known as bistable perception. The spontaneous alternation of perception might indicate a connection between bistable perception and the dynamic interaction of brain networks. Here, we hypothesized that individual differences in perceptual dynamics may be reflected in dynamics of spontaneous neural activities. To test this idea, we investigated the relationship between the percept duration and the reconfiguration patterns of dynamic brain networks as measured by the functional connectivity (FC) during the resting state. Firstly, we found that individual difference of percept duration is associated with the temporal variability of the brain regions which were previously reported in studies of bistable perception, including anterior cingulate cortex (ACC), dorsal medial prefrontal cortex (DMPFC), dorsal lateral prefrontal cortex (DLPFC), superior parietal lobule (SPL), inferior parietal lobule (IPL), precuneus, insula, and V5. Secondly, there is a positive relationship between the temporal variability within the frontal-parietal network (FPN) and the percept duration. Thirdly, our results indicated that individual difference of bistable perception was related to the dynamic interaction between large-scale functional networks including default mode network (DMN), FPN, cingulo-opercular network (CON), dorsal attention network (DAN), salience network (SN), memory retrieval network (MRN). Altogether, our results demonstrated that inter-individual variability in bistable perception was associated with dynamic coupling of brain regions and networks involved in primary visual processing, spatial attention, and cognitive control.
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Affiliation(s)
- Yu Mao
- Key Laboratory of Cognition and Personality (SWU), Ministry of Education, Chongqing, 400715, China; Department of Psychology, Southwest University, Chongqing, 400715, China
| | - Ryota Kanai
- Araya, Inc., Tokyo, Japan; Sackler Centre for Consciousness Science, University of Sussex, Brighton, UK
| | - Cody Ding
- Department of Psychology, Southwest University, Chongqing, 400715, China; Education Science & Professional Programs, University of Missouri-St. Louis, United States
| | - Taiyong Bi
- School of Management, Zunyi Medical University, Zunyi, 563000, China
| | - Jiang Qiu
- Key Laboratory of Cognition and Personality (SWU), Ministry of Education, Chongqing, 400715, China; Department of Psychology, Southwest University, Chongqing, 400715, China.
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Zhang C, Lee TMC, Fu Y, Ren C, Chan CCH, Tao Q. Properties of cross-modal occipital responses in early blindness: An ALE meta-analysis. NEUROIMAGE-CLINICAL 2019; 24:102041. [PMID: 31677587 PMCID: PMC6838549 DOI: 10.1016/j.nicl.2019.102041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/20/2019] [Accepted: 10/17/2019] [Indexed: 11/10/2022]
Abstract
ALE meta-analysis reveals distributed brain networks for object and spatial functions in individuals with early blindness. ALE contrast analysis reveals specific activations in the left cuneus and lingual gyrus for language function, suggesting a reverse hierarchical organization of the visual cortex for early blind individuals. The findings contribute to visual rehabilitation in blind individuals by revealing the function-dependent and sensory-independent networks during nonvisual processing.
Cross-modal occipital responses appear to be essential for nonvisual processing in individuals with early blindness. However, it is not clear whether the recruitment of occipital regions depends on functional domain or sensory modality. The current study utilized a coordinate-based meta-analysis to identify the distinct brain regions involved in the functional domains of object, spatial/motion, and language processing and the common brain regions involved in both auditory and tactile modalities in individuals with early blindness. Following the PRISMA guidelines, a total of 55 studies were included in the meta-analysis. The specific analyses revealed the brain regions that are consistently recruited for each function, such as the dorsal fronto-parietal network for spatial function and ventral occipito-temporal network for object function. This is consistent with the literature, suggesting that the two visual streams are preserved in early blind individuals. The contrast analyses found specific activations in the left cuneus and lingual gyrus for language function. This finding is novel and suggests a reverse hierarchical organization of the visual cortex for early blind individuals. The conjunction analyses found common activations in the right middle temporal gyrus, right precuneus and a left parieto-occipital region. Clinically, this work contributes to visual rehabilitation in early blind individuals by revealing the function-dependent and sensory-independent networks during nonvisual processing.
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Affiliation(s)
- Caiyun Zhang
- Psychology Department, School of Medicine, Jinan University, Guangzhou 510632, China
| | - Tatia M C Lee
- Laboratory of Neuropsychology, The University of Hong Kong, Hong Kong, CHINA; Laboratory of Cognitive Affective Neuroscience, The University of Hong Kong, Hong Kong, CHINA; The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Yunwei Fu
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, 510632, China
| | - Chaoran Ren
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, 510632, China; Guangdong key Laboratory of Brain Function and Diseases, Jinan University, Guangzhou, 510632, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China; Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong-Macao Greater Bay Area, Guangzhou, China
| | - Chetwyn C H Chan
- Applied Cognitive Neuroscience Laboratory, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong, CHINA.
| | - Qian Tao
- Psychology Department, School of Medicine, Jinan University, Guangzhou 510632, China; Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong-Macao Greater Bay Area, Guangzhou, China.
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Tarrano C, Wattiez N, Delorme C, McGovern EM, Brochard V, Thobois S, Tranchant C, Grabli D, Degos B, Corvol J, Pedespan J, Krystkoviak P, Houeto J, Degardin A, Defebvre L, Valabrègue R, Vidailhet M, Pouget P, Roze E, Worbe Y. Visual Sensory Processing is Altered in Myoclonus Dystonia. Mov Disord 2019; 35:151-160. [DOI: 10.1002/mds.27857] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 08/04/2019] [Accepted: 08/08/2019] [Indexed: 11/12/2022] Open
Affiliation(s)
- Clément Tarrano
- Sorbonne Université Paris, France; Inserm U1127, CNRS UMR 7225, UM 75, ICM Paris France
- Assistance Publique‐Hôpitaux de Paris, Centre d'Investigation Clinique Neurosciences, Hôpital Pitié‐Salpêtrière, Paris, France; Department of Neurology Groupe Hospitalier Pitié‐Salpêtrière Paris France
- Department of Neurology CHU Côte de Nacre, Université Caen Normandie Caen France
| | - Nicolas Wattiez
- Sorbonne Université, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique Paris France
| | - Cécile Delorme
- Sorbonne Université Paris, France; Inserm U1127, CNRS UMR 7225, UM 75, ICM Paris France
- Assistance Publique‐Hôpitaux de Paris, Centre d'Investigation Clinique Neurosciences, Hôpital Pitié‐Salpêtrière, Paris, France; Department of Neurology Groupe Hospitalier Pitié‐Salpêtrière Paris France
| | - Eavan M. McGovern
- Assistance Publique‐Hôpitaux de Paris, Centre d'Investigation Clinique Neurosciences, Hôpital Pitié‐Salpêtrière, Paris, France; Department of Neurology Groupe Hospitalier Pitié‐Salpêtrière Paris France
- Department of Neurology St Vincent's University Hospital Dublin Dublin Ireland
| | | | - Stéphane Thobois
- University of Lyon, Institut des Sciences Cognitives Marc Jeannerod, CNRS, UMR 5229, Bron, France; Hospices Civils de Lyon, Hôpital Neurologique Pierre Wertheimer, Service de Neurologie C Bron France
| | - Christine Tranchant
- Service de Neurologie Hôpitaux Universitaires de Strasbourg, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM‐U964/CNRS‐UMR7104/Université de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg Strasbourg France
| | - David Grabli
- Sorbonne Université Paris, France; Inserm U1127, CNRS UMR 7225, UM 75, ICM Paris France
- Assistance Publique‐Hôpitaux de Paris, Centre d'Investigation Clinique Neurosciences, Hôpital Pitié‐Salpêtrière, Paris, France; Department of Neurology Groupe Hospitalier Pitié‐Salpêtrière Paris France
| | - Bertrand Degos
- Assistance Publique‐Hôpitaux de Paris, Department of Neurology Hôpital Avicennes Bobigny France
| | - Jean‐Christophe Corvol
- Assistance Publique‐Hôpitaux de Paris, Centre d'Investigation Clinique Neurosciences, Hôpital Pitié‐Salpêtrière, Paris, France; Department of Neurology Groupe Hospitalier Pitié‐Salpêtrière Paris France
| | | | | | - Jean‐Luc Houeto
- Service de Neurologie, CIC‐INSERM 1402, CHU de Poitiers Poitiers France
| | - Adrian Degardin
- Department of Neurology Centre hospitalier de Tourcoing Tourcoing France
| | - Luc Defebvre
- Université de Lille, CHU Lille, INSERM, U1171–Degenerative & Vascular Cognitive Disorders, Lille, France; Lille Centre of Excellence for Neurodegenerative Diseases (LiCEND) Lille France
| | - Romain Valabrègue
- Sorbonne Université Paris, France; Inserm U1127, CNRS UMR 7225, UM 75, ICM Paris France
- Centre de NeuroImagerie de Recherche (CENIR) Sorbonne Université, UMR S 975, CNRS UMR 7225, ICM Paris France
| | - Marie Vidailhet
- Sorbonne Université Paris, France; Inserm U1127, CNRS UMR 7225, UM 75, ICM Paris France
- Assistance Publique‐Hôpitaux de Paris, Centre d'Investigation Clinique Neurosciences, Hôpital Pitié‐Salpêtrière, Paris, France; Department of Neurology Groupe Hospitalier Pitié‐Salpêtrière Paris France
| | - Pierre Pouget
- Sorbonne Université Paris, France; Inserm U1127, CNRS UMR 7225, UM 75, ICM Paris France
| | - Emmanuel Roze
- Sorbonne Université Paris, France; Inserm U1127, CNRS UMR 7225, UM 75, ICM Paris France
- Assistance Publique‐Hôpitaux de Paris, Centre d'Investigation Clinique Neurosciences, Hôpital Pitié‐Salpêtrière, Paris, France; Department of Neurology Groupe Hospitalier Pitié‐Salpêtrière Paris France
| | - Yulia Worbe
- Sorbonne Université Paris, France; Inserm U1127, CNRS UMR 7225, UM 75, ICM Paris France
- Department of Neurophysiology Saint‐Antoine Hospital, Assistance Publique‐Hôpitaux de Paris Paris France
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Chen Z, Zhao X, Fan J, Chen A. Functional cerebral asymmetry analyses reveal how the control system implements its flexibility. Hum Brain Mapp 2018; 39:4678-4688. [PMID: 30015380 DOI: 10.1002/hbm.24313] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 06/29/2018] [Accepted: 07/02/2018] [Indexed: 12/23/2022] Open
Abstract
The control system in human brain generally exerts the goal-directed regulation on a variety of mental processes. To deal with different control demands, these brain areas of the control system, especially the dorsolateral prefrontal cortex (DLPFC), may be flexibly recruited across different tasks. However, few studies have investigated how the flexibility of the control system is realized during cognitive control. Present study employed functional magnetic resonance imaging to examine the brain responses during two domain distinct conflict tasks (verbal color-word Stroop and visuospatial arrow flanker). The voxel-wise asymmetries in both functional activity and psychophysiological interaction (PPI) between these two tasks were compared. The results showed that the brain areas of control system were consistently activated in these two tasks. When considering functional cerebral asymmetries, the left DLPFC was dominantly activated during the Stroop task, while more symmetric DLPFC activation was found during the flanker task. The left DLPFC rather than the right DLPFC showed greater positive interaction with the visual areas V1 and V2 during the Stroop interference, but interactions of both the left and right DLPFC with the right visual area V5/MT were positively enhanced during the flanker interference. These results suggest that the flexible cognitive control is achieved by the control system's task-specific activity and its top-down interaction with domain-specific brain areas, in implementing flexible representation and modulation of control demands.
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Affiliation(s)
- Zhencai Chen
- Department of Psychology, Jiangxi University of Traditional Chinese Medicine, Nanchang, China
| | - Xiaoyue Zhao
- Key Laboratory of Cognition and Personality of Ministry of Education, Faculty of Psychology, Southwest University, Chongqing, China
| | - Jin Fan
- Department of Psychology, Queens College, The City University of New York, Icahn School of Medicine at Mount Sinai, New York City, New York.,Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York City, New York.,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York City, New York
| | - Antao Chen
- Key Laboratory of Cognition and Personality of Ministry of Education, Faculty of Psychology, Southwest University, Chongqing, China
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Taylor CM, Olulade OA, Luetje MM, Eden GF. An fMRI study of coherent visual motion processing in children and adults. Neuroimage 2018; 173:223-239. [PMID: 29477442 DOI: 10.1016/j.neuroimage.2018.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 01/24/2018] [Accepted: 02/01/2018] [Indexed: 12/30/2022] Open
Abstract
There is a large corpus of brain imaging studies examining the dorsal visual pathway, especially area V5/MT during visual motion perception. However, despite evidence suggesting a protracted development of the dorsal visual stream, and a role of this pathway in neurodevelopmental disorders, V5/MT has not been characterized developmentally. Further, experiential factors such as reading acquisition may play a modulating role in any age-dependent changes. Here we used a coherent visual motion detection task to examine V5/MT activity and connectivity in typical participants in two studies: a Cross- Sectional Study comparing adults and children; and a Longitudinal Study of 2nd graders followed into 3rd grade. In the Cross-Sectional Study, a whole-brain analysis revealed no differences between the two groups, whereas a region of interest (ROI) approach identified greater activation in left (right trending) V5/MT in adults compared to children. However, when we measured V5/MT activation individually for each participant, children and adults showed no difference in the location or intensity of activation, although children did exhibit relatively larger extent of V5/MT activation bilaterally. There was also relatively greater functional connectivity in the children between left and right occipitotemporal cortex, including V5/MT. The Longitudinal Study revealed no changes in V5/MT activation for any measures of activation or functional connectivity from 2nd to 3rd grade. Finally, there was no evidence of an association between reading and V5/MT over time, nor predictive power of V5/MT activity for later reading. Together, our results indicate similar V5/MT activity across age groups, with relatively greater extent of V5/MT activation and functional connectivity in children relative to adults, bilaterally. These differences were not apparent over the time course of one year, suggesting that these developmental changes occur over a more protracted period.
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Affiliation(s)
- C M Taylor
- Center for the Study of Learning, Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA
| | - O A Olulade
- Center for the Study of Learning, Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA
| | - M M Luetje
- Center for the Study of Learning, Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA
| | - G F Eden
- Center for the Study of Learning, Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA.
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10
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Ogourtsova T, Archambault P, Sangani S, Lamontagne A. Ecological Virtual Reality Evaluation of Neglect Symptoms (EVENS): Effects of Virtual Scene Complexity in the Assessment of Poststroke Unilateral Spatial Neglect. Neurorehabil Neural Repair 2018; 32:46-61. [DOI: 10.1177/1545968317751677] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background. Unilateral spatial neglect (USN) is a highly prevalent and disabling poststroke impairment. USN is traditionally assessed with paper-and-pencil tests that lack ecological validity, generalization to real-life situations and are easily compensated for in chronic stages. Virtual reality (VR) can, however, counteract these limitations. Objective. We aimed to examine the feasibility of a novel assessment of USN symptoms in a functional shopping activity, the Ecological VR-based Evaluation of Neglect Symptoms (EVENS). Methods. EVENS is immersive and consists of simple and complex 3-dimensional scenes depicting grocery shopping shelves, where joystick-based object detection and navigation tasks are performed while seated. Effects of virtual scene complexity on navigational and detection abilities in patients with (USN+, n = 12) and without (USN−, n = 15) USN following a right hemisphere stroke and in age-matched healthy controls (HC, n = 9) were determined. Results. Longer detection times, larger mediolateral deviations from ideal paths and longer navigation times were found in USN+ versus USN− and HC groups, particularly in the complex scene. EVENS detected lateralized and nonlateralized USN-related deficits, performance alterations that were dependent or independent of USN severity, and performance alterations in 3 USN− subjects versus HC. Conclusion. EVENS’ environmental changing complexity, along with the functional tasks of far space detection and navigation can potentially be clinically relevant and warrant further empirical investigation. Findings are discussed in terms of attentional models, lateralized versus nonlateralized deficits in USN, and tasks-specific mechanisms.
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Affiliation(s)
- Tatiana Ogourtsova
- McGill University, Montreal, Quebec, Canada
- Jewish Rehabilitation Hospital, Laval, Quebec, Canada
| | - Philippe Archambault
- McGill University, Montreal, Quebec, Canada
- Jewish Rehabilitation Hospital, Laval, Quebec, Canada
| | - Samir Sangani
- Jewish Rehabilitation Hospital, Laval, Quebec, Canada
| | - Anouk Lamontagne
- McGill University, Montreal, Quebec, Canada
- Jewish Rehabilitation Hospital, Laval, Quebec, Canada
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11
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Meier K, Giaschi D. Effect of spatial and temporal stimulus parameters on the maturation of global motion perception. Vision Res 2017; 135:1-9. [PMID: 28414023 DOI: 10.1016/j.visres.2017.04.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/31/2017] [Accepted: 04/11/2017] [Indexed: 02/03/2023]
Abstract
There are discrepancies with respect to the age at which adult-like performance is reached on tasks assessing global motion perception. This is in part because performance in children depends on stimulus parameters. We recently showed that five-year-olds demonstrated adult-like performance over a range of speeds when the speed ratio was comprised of longer spatial and temporal displacements; but displayed immature performance when the speed ratio was comprised of shorter displacements. The goal of the current study was to assess the effect of these global motion stimulus parameters across a broader age range in order to estimate the age at which mature performance is reached. Motion coherence thresholds were assessed in 182 children and adults aged 7-30years. Dot displacement (Δx) was 1, 5, or 30min of arc; frame duration (Δt) was 17 or 50ms. This created a total of six conditions. Consistent with our previous results, coherence thresholds in the youngest children assessed were adult-like at the two conditions with the largest Δx. Maturity was reached around age 12 for the medium Δx, and by age 16 for the smallest Δx. Performance did not appear to be affected by Δt. This late maturation may reflect a long developmental period for cortical networks underlying global motion perception. These findings resolve many of the discrepancies across previous studies, and should be considered when using global motion tasks to assess children with atypical development.
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Affiliation(s)
- Kimberly Meier
- Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, B.C. V6T 1Z4, Canada.
| | - Deborah Giaschi
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Rm E300E, 4480 Oak Street, Vancouver, B.C. V6H 3V4, Canada.
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12
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Thompson CA, Karelis J, Middleton FA, Gentile K, Coman IL, Radoeva PD, Mehta R, Fremont WP, Antshel KM, Faraone SV, Kates WR. Associations between neurodevelopmental genes, neuroanatomy, and ultra high risk symptoms of psychosis in 22q11.2 deletion syndrome. Am J Med Genet B Neuropsychiatr Genet 2017; 174:295-314. [PMID: 28139055 DOI: 10.1002/ajmg.b.32515] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 11/07/2016] [Indexed: 11/06/2022]
Abstract
22q11.2 deletion syndrome is a neurogenetic disorder resulting in the deletion of over 40 genes. Up to 40% of individuals with 22q11.2DS develop schizophrenia, though little is known about the underlying mechanisms. We hypothesized that allelic variation in functional polymorphisms in seven genes unique to the deleted region would affect lobar brain volumes, which would predict risk for psychosis in youth with 22q11.2DS. Participants included 56 individuals (30 males) with 22q11.2DS. Anatomic MR images were collected and processed using Freesurfer. Participants were genotyped for 10 SNPs in the COMT, DGCR8, GNB1L, PIK4CA, PRODH, RTN4R, and ZDHHC8 genes. All subjects were assessed for ultra high risk symptoms of psychosis. Allelic variation of the rs701428 SNP of RTN4R was significantly associated with volumetric differences in gray matter of the lingual gyrus and cuneus of the occipital lobe. Moreover, occipital gray matter volumes were robustly associated with ultra high risk symptoms of psychosis in the presence of the G allele of rs701428. Our results suggest that RTN4R, a relatively under-studied gene at the 22q11 locus, constitutes a susceptibility gene for psychosis in individuals with this syndrome through its alteration of the architecture of the brain. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Carlie A Thompson
- Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, New York
| | - Jason Karelis
- Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, New York
| | - Frank A Middleton
- Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, New York.,Department of Neuroscience, SUNY Upstate Medical University, Syracuse, New York
| | - Karen Gentile
- Department of Neuroscience, SUNY Upstate Medical University, Syracuse, New York
| | - Ioana L Coman
- Department of Computer Science, SUNY Oswego, Oswego, New York
| | - Petya D Radoeva
- Department of Psychiatry, University of Washington, Seattle, Washington
| | - Rashi Mehta
- Department of Radiology, SUNY Upstate Medical University, Syracuse, New York
| | - Wanda P Fremont
- Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, New York
| | - Kevin M Antshel
- Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, New York.,Department of Psychology, Syracuse University, Syracuse, New York
| | - Stephen V Faraone
- Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, New York
| | - Wendy R Kates
- Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, New York
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13
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Cakmak YO, Ekinci G, Heinecke A, Çavdar S. A Possible Role of Prolonged Whirling Episodes on Structural Plasticity of the Cortical Networks and Altered Vertigo Perception: The Cortex of Sufi Whirling Dervishes. Front Hum Neurosci 2017; 11:3. [PMID: 28167905 PMCID: PMC5253366 DOI: 10.3389/fnhum.2017.00003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 01/03/2017] [Indexed: 12/14/2022] Open
Abstract
Although minutes of a spinning episode may induce vertigo in the healthy human, as a result of a possible perceptional plasticity, Sufi Whirling Dervishes (SWDs) can spin continuously for an hour without a vertigo perception.This unique long term vestibular system stimulation presents a potential human model to clarify the cortical networks underlying the resistance against vertigo. This study, therefore, aimed to investigate the potential structural cortical plasticity in SWDs. Magnetic resonance imaging (MRI) of 10 SWDs and 10 controls were obtained, using a 3T scanner. Cortical thickness in the whole cortex was calculated. Results demonstrated significantly thinner cortical areas for SWD subjects compared with the control group in the hubs of the default mode network (DMN), as well as in the motion perception and discrimination areas including the right dorsolateral prefrontal cortex (DLPFC), the right lingual gyrus and the left visual area 5 (V5)/middle temporal (MT) and the left fusiform gyrus. In conclusion, this is the first report that warrants the potential relationship of the motion/body perception related cortical networks and the prolonged term of whirling ability without vertigo or dizziness.
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Affiliation(s)
- Yusuf O Cakmak
- Department of Anatomy, School of Biomedical Sciences, University of Otago Dunedin, New Zealand
| | - Gazanfer Ekinci
- Radiology Department, School of Medicine, Marmara University Istanbul, Turkey
| | - Armin Heinecke
- Brain Innovation BV, Biopartner Center Maastricht, Netherlands
| | - Safiye Çavdar
- Department of Anatomy, School of Medicine, Koc University Istanbul, Turkey
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14
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Global versus local: double dissociation between MT+ and V3A in motion processing revealed using continuous theta burst transcranial magnetic stimulation. Exp Brain Res 2014; 232:4035-41. [DOI: 10.1007/s00221-014-4084-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 08/23/2014] [Indexed: 11/25/2022]
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15
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Van Impe A, Bruijn SM, Coxon JP, Wenderoth N, Sunaert S, Duysens J, Swinnen SP. Age-related neural correlates of cognitive task performance under increased postural load. AGE (DORDRECHT, NETHERLANDS) 2013; 35:2111-24. [PMID: 23274853 PMCID: PMC3824995 DOI: 10.1007/s11357-012-9499-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 12/05/2012] [Indexed: 05/07/2023]
Abstract
Behavioral studies suggest that postural control requires increased cognitive control and visuospatial processing with aging. Consequently, performance can decline when concurrently performing a postural and a demanding cognitive task. We aimed to identify the neural substrate underlying this effect. A demanding cognitive task, requiring visuospatial transformations, was performed with varying postural loads. More specifically, old and young subjects performed mental rotations of abstract figures in a seated position and when standing on a force platform. Additionally, functional magnetic resonance imaging (fMRI) was used to identify brain regions associated with mental rotation performance. Old as compared to young subjects showed increased blood oxygenation level-dependent (BOLD) responses in a frontoparietal network as well as activations in additional areas. Despite this overall increased activation, they could still modulate BOLD responses with increasing task complexity. Importantly, activity in left lingual gyrus was highly predictive (r = -0.83, adjusted R(2) = 0.65) of the older subjects' degree of success in mental rotation performance when shifting from a sitting to a standing position. More specifically, increased activation in this area was associated with better performance, once postural load increased.
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Affiliation(s)
- A. Van Impe
- />Research Center for Movement Control and Neuroplasticity, K.U. Leuven, Leuven, Belgium
- />Movement Control and Neuroplasticity Research Group, Group Biomedical Sciences, Tervuursevest 101, 3001 Heverlee, Belgium
| | - S. M. Bruijn
- />Research Center for Movement Control and Neuroplasticity, K.U. Leuven, Leuven, Belgium
| | - J. P. Coxon
- />Research Center for Movement Control and Neuroplasticity, K.U. Leuven, Leuven, Belgium
| | - N. Wenderoth
- />Research Center for Movement Control and Neuroplasticity, K.U. Leuven, Leuven, Belgium
| | - S. Sunaert
- />Department of Radiology, University Hospital, K.U. Leuven, Leuven, Belgium
| | - J. Duysens
- />Research Center for Movement Control and Neuroplasticity, K.U. Leuven, Leuven, Belgium
- />Department of Research, Development and Education, Sint-Maartenskliniek, Nijmegen, The Netherlands
| | - S. P. Swinnen
- />Research Center for Movement Control and Neuroplasticity, K.U. Leuven, Leuven, Belgium
- />Movement Control and Neuroplasticity Research Group, Group Biomedical Sciences, Tervuursevest 101, 3001 Heverlee, Belgium
- />Leuven Research Institute for Neuroscience & Disease O&N4, Herestraat 49, box 602, 3000 Leuven, Belgium
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16
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Smith AT, Wall MB, Thilo KV. Vestibular inputs to human motion-sensitive visual cortex. ACTA ACUST UNITED AC 2011; 22:1068-77. [PMID: 21743097 DOI: 10.1093/cercor/bhr179] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Two crucial sources of information available to an organism when moving through an environment are visual and vestibular stimuli. Macaque cortical area MSTd processes visual motion, including cues to self-motion arising from optic flow and also receives information about self-motion from the vestibular system. In humans, whether human MST (hMST) receives vestibular afferents is unknown. We have combined 2 techniques, galvanic vestibular stimulation and functional MRI (fMRI), to show that hMST is strongly activated by vestibular stimulation in darkness, whereas adjacent area MT is unaffected. The activity cannot be explained in terms of somatosensory stimulation at the electrode site. Vestibular input appears to be confined to the anterior portion of hMST, suggesting that hMST as conventionally defined may contain 2 subregions. Vestibular activity was also seen in another area previously implicated in processing visual cues to self-motion, namely the cingulate sulcus visual area (CSv), but not in visual area V6. The results suggest that cross-modal convergence of cues to self-motion occurs in both hMST and CSv.
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Affiliation(s)
- Andrew T Smith
- Department of Psychology, Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK.
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17
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Tinelli F, Guzzetta A, Bertini C, Ricci D, Mercuri E, Ladavas E, Cioni G. Greater Sparing of Visual Search Abilities in Children After Congenital Rather Than Acquired Focal Brain Damage. Neurorehabil Neural Repair 2011; 25:721-8. [PMID: 21646445 DOI: 10.1177/1545968311407780] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background. Visual search refers to the capacity of an individual to find a target among simultaneously presented distracters and is based on visual abilities such as a fast visual processing and an accurate control of ballistic eye movements (saccades) that guide the fovea to the target location. Objective. In adults, visual field defects caused by brain damage are often associated with visual search disorders; in children, little is known about the effects of early brain lesions on visual search abilities. Methods. To test the presence of visual search defects and to investigate the role of cortical plasticity after early brain lesions, 29 children with congenital or acquired cerebral lesions, with and without visual field defects, underwent a visual search test battery. Results. The children with acquired lesions and visual field defects had longer reaction times (RTs) in the contralesional visual field compared with the ipsilesional, whereas those with congenital lesions and visual field defects did not have differences in RTs between the contralateral and ipsilateral visual fields and had a visual search pattern similar to children without a visual field defect. Conclusions. These findings support the hypothesis of more effective mechanisms of functional compensation and reorganization of the visual system in children with very early brain lesions, as opposed to those with later damage.
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Affiliation(s)
| | | | | | | | | | | | - Giovanni Cioni
- Stella Maris Scientific Institute, Pisa, Italy
- University of Pisa, Pisa, Italy
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18
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Functional specialization for auditory-spatial processing in the occipital cortex of congenitally blind humans. Proc Natl Acad Sci U S A 2011; 108:4435-40. [PMID: 21368198 DOI: 10.1073/pnas.1013928108] [Citation(s) in RCA: 246] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The study of the congenitally blind (CB) represents a unique opportunity to explore experience-dependant plasticity in a sensory region deprived of its natural inputs since birth. Although several studies have shown occipital regions of CB to be involved in nonvisual processing, whether the functional organization of the visual cortex observed in sighted individuals (SI) is maintained in the rewired occipital regions of the blind has only been recently investigated. In the present functional MRI study, we compared the brain activity of CB and SI processing either the spatial or the pitch properties of sounds carrying information in both domains (i.e., the same sounds were used in both tasks), using an adaptive procedure specifically designed to adjust for performance level. In addition to showing a substantial recruitment of the occipital cortex for sound processing in CB, we also demonstrate that auditory-spatial processing mainly recruits the right cuneus and the right middle occipital gyrus, two regions of the dorsal occipital stream known to be involved in visuospatial/motion processing in SI. Moreover, functional connectivity analyses revealed that these reorganized occipital regions are part of an extensive brain network including regions known to underlie audiovisual spatial abilities (i.e., intraparietal sulcus, superior frontal gyrus). We conclude that some regions of the right dorsal occipital stream do not require visual experience to develop a specialization for the processing of spatial information and to be functionally integrated in a preexisting brain network dedicated to this ability.
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19
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Paradis AL, Droulez J, Cornilleau-Pérès V, Poline JB. Processing 3D form and 3D motion: respective contributions of attention-based and stimulus-driven activity. Neuroimage 2008; 43:736-47. [PMID: 18805496 DOI: 10.1016/j.neuroimage.2008.08.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 07/31/2008] [Accepted: 08/19/2008] [Indexed: 11/30/2022] Open
Abstract
This study aims at segregating the neural substrate for the 3D-form and 3D-motion attributes in structure-from-motion perception, and at disentangling the stimulus-driven and endogenous-attention-driven processing of these attributes. Attention and stimulus were manipulated independently: participants had to detect the transitions of one attribute--form, 3D motion or colour--while the visual stimulus underwent successive transitions of all attributes. We compared the BOLD activity related to form and 3D motion in three conditions: stimulus-driven processing (unattended transitions), endogenous attentional selection (task) or both stimulus-driven processing and attentional selection (attended transitions). In all conditions, the form versus 3D-motion contrasts revealed a clear dorsal/ventral segregation. However, while the form-related activity is consistent with previously described shape-selective areas, the activity related to 3D motion does not encompass the usual "visual motion" areas, but rather corresponds to a high-level motion system, including IPL and STS areas. Second, we found a dissociation between the neural processing of unattended attributes and that involved in endogenous attentional selection. Areas selective for 3D-motion and form showed either increased activity at transitions of these respective attributes or decreased activity when subjects' attention was directed to a competing attribute. We propose that both facilitatory and suppressive mechanisms of attribute selection are involved depending on the conditions driving this selection. Therefore, attentional selection is not limited to an increased activity in areas processing stimulus properties, and may unveil different functional localization from stimulus modulation.
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Affiliation(s)
- A-L Paradis
- CNRS, UPR640, Laboratoire de Neurosciences Cognitives et Imagerie Cérébrale, 75013 Paris, France.
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20
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The posterior cingulate cortex and planum temporale/parietal operculum are activated by coherent visual motion. Vis Neurosci 2008; 25:17-26. [PMID: 18282307 DOI: 10.1017/s0952523808080024] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Accepted: 11/06/2007] [Indexed: 11/07/2022]
Abstract
The posterior cingulate cortex (PCC) is involved in higher order sensory and sensory-motor integration while the planum temporale/parietal operculum (PT/PO) junction takes part in auditory motion and vestibular processing. Both regions are activated during different types of visual stimulation. Here, we describe the response characteristics of the PCC and PT/PO to basic types of visual motion stimuli of different complexity (complex and simple coherent as well as incoherent motion). Functional magnetic resonance imaging (fMRI) was performed in 10 healthy subjects at 3 Tesla, whereby different moving dot stimuli (vertical, horizontal, rotational, radial, and random) were contrasted against a static dot pattern. All motion stimuli activated a distributed cortical network, including previously described motion-sensitive striate and extrastriate visual areas. Bilateral activations in the dorsal region of the PCC (dPCC) were evoked using coherent motion stimuli, irrespective of motion direction (vertical, horizontal, rotational, radial) with increasing activity and with higher complexity of the stimulus. In contrast, the PT/PO responded equally well to all of the different coherent motion types. Incoherent (random) motion yielded significantly less activation both in the dPCC and in the PT/PO area. These results suggest that the dPCC and the PT/PO take part in the processing of basic types of visual motion. However, in dPCC a possible effect of attentional modulation resulting in the higher activity evoked by the complex stimuli should also be considered. Further studies are warranted to incorporate these regions into the current model of the cortical motion processing network.
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21
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Morrone MC, Guzzetta A, Tinelli F, Tosetti M, Del Viva M, Montanaro D, Burr D, Cioni G. Inversion of Perceived Direction of Motion Caused by Spatial Undersampling in Two Children with Periventricular Leukomalacia. J Cogn Neurosci 2008; 20:1094-106. [DOI: 10.1162/jocn.2008.20061] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Abstract
We report here two cases of two young diplegic patients with cystic periventricular leukomalacia who systematically, and with high sensitivity, perceive translational motion of a random-dot display in the opposite direction. The apparent inversion was specific for translation motion: Rotation and expansion motion were perceived correctly, with normal sensitivity. It was also specific for random-dot patterns, not occurring with gratings. For the one patient that we were able to test extensively, contrast sensitivity for static stimuli was normal, but was very low for direction discrimination at high spatial frequencies and all temporal frequencies. His optokinetic nystagmus movements were normal but he was unable to track a single translating target, indicating a perceptual origin of the tracking deficit. The severe deficit for motion perception was also evident in the seminatural situation of a driving simulation video game. The perceptual deficit for translational motion was reinforced by functional magnetic resonance imaging studies. Translational motion elicited no response in the MT complex, although it did produce a strong response in many visual areas when contrasted with blank stimuli. However, radial and rotational motion produced a normal pattern of activation in a subregion of the MT complex. These data reinforce the existent evidence for independent cortical processing for translational, and circular or radial flow motion, and further suggest that the two systems have different vulnerability and plasticity to prenatal damage. They also highlight the complexity of visual motion perception, and how the delicate balance of neural activity can lead to paradoxical effects such as consistent misperception of the direction of motion. We advance a possible explanation of a reduced spatial sampling of the motion stimuli and report a simple model that simulates well the experimental results.
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Affiliation(s)
- Maria Concetta Morrone
- 1Università Vita-Salute San Raffaele, and Instituto Italiano di Science, Milan, Italy
- 2Institute of Neuroscience, CNR, Pisa, Italy
| | | | - Francesca Tinelli
- 3Stella Maris Scientific Institute, Pisa, Italy
- 4University of Pisa, Italy
| | | | - Michela Del Viva
- 2Institute of Neuroscience, CNR, Pisa, Italy
- 5University of Florence, Italy
| | | | - David Burr
- 2Institute of Neuroscience, CNR, Pisa, Italy
- 5University of Florence, Italy
- 7University of Western Australia, Perth, Australia
| | - Giovanni Cioni
- 3Stella Maris Scientific Institute, Pisa, Italy
- 4University of Pisa, Italy
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22
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Dorsal stream development in motion and structure-from-motion perception. Neuroimage 2007; 39:1815-23. [PMID: 18096410 DOI: 10.1016/j.neuroimage.2007.11.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Revised: 11/01/2007] [Accepted: 11/13/2007] [Indexed: 11/21/2022] Open
Abstract
Little is known about the neural development underlying high order visual perception. For example, in detection of structures by coherently moving dots, motion information must interact with shape-based information to enable object recognition. Tasks involving these different motion-based discriminations are known to activate distinct specialized brain areas in adults. Here, we investigate neural development of normally developing children using functional magnetic resonance imaging (fMRI) during perception of randomly moving point-light dots (RM), coherently moving dots that formed a 3D rotating object (SFM) and static dots. Perception of RM enhanced neural activity as compared with static dots in motion processing-related visual areas, including visual area 3a (V3a), and middle temporal area (hMT+) in 10 adults (age 20-30 years). Children (age 5-6 years) showed less pronounced activity in area V3a than adults. Perception of SFM induced enhanced neural activity as compared to RM in adults in the left parietal shape area (PSA), whereas children increased neural activity within dorsal (V3a) and ventral brain areas (lingual gyrus) of the occipital cortex. These findings provide evidence of neural development within the dorsal pathway. First, maturation was associated with enhanced activity in specialized areas within the dorsal pathway during RM perception (V3a) and SFM perception (PSA). Secondly, high order visual perception-related neural development was associated with a shift in neural activity from low level shape and motion specialized areas in children, including partially immature area V3a, to high order areas in the parietal lobule (PSA) in adults.
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23
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Tong J, Aydin M, Bedell HE. Direction-of-motion discrimination is facilitated by visible motion smear. ACTA ACUST UNITED AC 2007; 69:48-55. [PMID: 17515215 DOI: 10.3758/bf03194452] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recent evidence indicates that motion smear can provide useful information for the detection and discrimination of motion. Further, it has been shown that the perception of motion smear depends critically on the density of dots in a random-dot (RD) stimulus. Therefore, in the present experiments, the contribution of perceived motion smear to direction-of-motion discrimination was evaluated using RD targets of different densities. Thresholds for direction-of-motion discrimination and the extent of perceived motion smear were determined for RD stimuli with densities of 1, 2, and 10 dots/deg(2), presented for 200 msec at a velocity of 4, 8, or 12 deg/sec. To evaluate the contribution of information about orientation from motion smear, thresholds for orientation discrimination were measured using parallel lines with the same length as the extent of perceived smear. Despite the opportunity for increased summation as RD density increases, our results indicate that direction-of-motion discrimination worsens. Because perception of motion smear is reduced with an increase in RD density, our results are consistent with a facilitation of direction-of-motion discrimination by visible motion smear.
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Martinez-Trujillo JC, Cheyne D, Gaetz W, Simine E, Tsotsos JK. Activation of Area MT/V5 and the Right Inferior Parietal Cortex during the Discrimination of Transient Direction Changes in Translational Motion. Cereb Cortex 2006; 17:1733-9. [PMID: 17012375 DOI: 10.1093/cercor/bhl084] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The perception of changes in the direction of objects that translate in space is an important function of our visual system. Here we investigate the brain electrical phenomena underlying such a function by using a combination of magnetoencephalography (MEG) and magnetic resonance imaging. We recorded MEG-evoked responses in 9 healthy human subjects while they discriminated the direction of a transient change in a translationally moving random dot pattern presented either to the right or to the left of a central fixation point. We found that responses reached their maximum in 2 main regions corresponding to motion processing area middle temporal (MT)/V5 contralateral to the stimulated visual field, and to the right inferior parietal lobe (rIPL). The activation latencies were very similar in both regions ( approximately 135 ms) following the direction change onset. Our findings suggest that area MT/V5 provides the strongest sensory signal in response to changes in the direction of translational motion, whereas area rIPL may be involved either in the sensory processing of transient motion signals or in the processing of signals related to orienting of attention.
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Sapir A, d'Avossa G, McAvoy M, Shulman GL, Corbetta M. Brain signals for spatial attention predict performance in a motion discrimination task. Proc Natl Acad Sci U S A 2005; 102:17810-5. [PMID: 16306268 PMCID: PMC1308888 DOI: 10.1073/pnas.0504678102] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The reliability of visual perception is thought to reflect the quality of the sensory information. However, we show that subjects' performance can be predicted, trial-by-trial, by neural activity that precedes the onset of a sensory stimulus. Using functional MRI (fMRI), we studied how neural mechanisms that mediate spatial attention affect the accuracy of a motion discrimination judgment. The amplitude of blood oxygen level-dependent (BOLD) signals after a cue directing spatial attention predicted subjects' accuracy on 60-75% of the trials. Widespread predictive signals, which included dorsal parietal, visual extra-striate, prefrontal and sensory-motor cortex, depended on whether the cue correctly specified the stimulus location. Therefore, these signals indicate the degree of utilization of the cued information and play a role in the control of spatial attention. We conclude that variability in perceptual performance can be partly explained by the variability in endogenous, preparatory processes and that BOLD signals can be used to forecast human behavior.
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Affiliation(s)
- Ayelet Sapir
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
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26
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Meegan DV, Honsberger MJM. Spatial information is processed even when it is task-irrelevant: implications for neuroimaging task design. Neuroimage 2005; 25:1043-55. [PMID: 15850723 DOI: 10.1016/j.neuroimage.2004.12.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2004] [Revised: 11/30/2004] [Accepted: 12/01/2004] [Indexed: 01/28/2023] Open
Abstract
Many neuroimaging studies have been designed to differentiate domain-specific processes in the brain. A common design constraint is to use identical stimuli for different domain-specific tasks. For example, an experiment investigating spatial versus identity processing would present compound spatial-identity stimuli in both spatial and identity tasks, and participants would be instructed to attend to, encode, maintain, or retrieve spatial information in the spatial task, and identity information in the identity task. An assumption in such studies is that spatial information will not be processed in the identity task, as it is irrelevant for that task. We report three experiments demonstrating violations of this assumption. Our results suggest that comparisons of spatial and identity tasks in existing neuroimaging studies have underestimated the amount of brain activation that is spatial-specific. For future neuroimaging studies, we recommend unique stimulus displays for each domain-specific task, and event-related measurement of post-stimulus processing.
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Affiliation(s)
- Daniel V Meegan
- Department of Psychology, University of Guelph, Guelph, ON, Canada N1G 2W1.
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27
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Schneider KA, Kastner S. Visual responses of the human superior colliculus: a high-resolution functional magnetic resonance imaging study. J Neurophysiol 2005; 94:2491-503. [PMID: 15944234 DOI: 10.1152/jn.00288.2005] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The superior colliculus (SC) is a multimodal laminar structure located on the roof of the brain stem. The SC is a key structure in a distributed network of areas that mediate saccadic eye movements and shifts of attention across the visual field and has been extensively studied in nonhuman primates. In humans, it has proven difficult to study the SC with functional MRI (fMRI) because of its small size, deep location, and proximity to pulsating vascular structures. Here, we performed a series of high-resolution fMRI studies at 3 T to investigate basic visual response properties of the SC. The retinotopic organization of the SC was determined using the traveling wave method with flickering checkerboard stimuli presented at different polar angles and eccentricities. SC activations were confined to stimulation of the contralateral hemifield. Although a detailed retinotopic map was not observed, across subjects, the upper and lower visual fields were represented medially and laterally, respectively. Responses were dominantly evoked by stimuli presented along the horizontal meridian of the visual field. We also measured the sensitivity of the SC to luminance contrast, which has not been previously reported in primates. SC responses were nearly saturated by low contrast stimuli and showed only small response modulation with higher contrast stimuli, indicating high sensitivity to stimulus contrast. Responsiveness to stimulus motion in the SC was shown by robust activations evoked by moving versus static dot stimuli that could not be attributed to eye movements. The responses to contrast and motion stimuli were compared with those in the human lateral geniculate nucleus. Our results provide first insights into basic visual responses of the human SC and show the feasibility of studying subcortical structures using high-resolution fMRI.
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Prohovnik I, Skudlarski P, Fulbright RK, Gore JC, Wexler BE. Functional MRI changes before and after onset of reported emotions. Psychiatry Res 2004; 132:239-50. [PMID: 15664795 DOI: 10.1016/j.pscychresns.2004.03.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2002] [Revised: 05/15/2003] [Accepted: 03/25/2004] [Indexed: 10/26/2022]
Abstract
The social nature of emotion is evident in the importance of facial and vocal displays in emotion-related behavior. This is the first brain-imaging study to use simulated face-to-face social interactions to evoke emotional responses and to compare valence-related activations before and after subjective onset of emotional response. Videotapes were prepared with actresses who described happy or unhappy experiences. Functional magnetic resonance imaging (fMRI) at 1.5 T was used to acquire BOLD images in 21 healthy young adults before, after, and during viewing of the happy and sad tapes. Subjects pushed buttons to indicate the onset of subjective emotional responses. Group data were analyzed by a bootstrap randomization method after anatomical normalization. Significant activation was detected in frontal and sensory regions prior to the reported onset of emotional response, and this activity showed a marked decrease after the report of conscious emotional experience. Significant differences between happy and sad conditions were evident in multiple brain regions both before and after the reported onset of emotional response, including the middle and superior temporal gyri, the middle frontal gyrus, the caudate, and the hippocampus. Socially relevant emotional stimulation is feasible and evokes robust responses. The neural correlates of the evoked emotion are multiple, widely distributed, and inclusive of areas important in many cognitive tasks. Positive and negative emotional responses include activation of common and distinctive brain regions.
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Affiliation(s)
- Isak Prohovnik
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, USA.
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29
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Vafaee MS, ØStergaard K, Sunde N, Gjedde A, Dupont E, Cumming P. Focal changes of oxygen consumption in cerebral cortex of patients with Parkinson's disease during subthalamic stimulation. Neuroimage 2004; 22:966-74. [PMID: 15193628 DOI: 10.1016/j.neuroimage.2004.02.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2003] [Revised: 02/07/2004] [Accepted: 02/07/2004] [Indexed: 01/23/2023] Open
Abstract
Motor symptoms of Parkinson's disease (PD) are substantially improved by bilateral high-frequency electrical stimulation of the subthalamic nucleus (STN). Altered cerebral blood flow (CBF) in a network of frontal cortical and subcortical structures has been reported in numerous studies of patients undergoing subthalamic stimulation. However, CBF is a controversial indicator of brain activation because measures of blood flow bear a variable relation to measures of brain work and energy metabolism. We hypothesized that STN stimulation would alter the rate of oxygen consumption (CMRO(2)) in cerebral cortical areas in proportion to previously reported changes in CBF in patients undergoing stimulation at rest. We used quantitative PET to map CMRO(2) in brain of seven patients with Parkinson's disease, first in a baseline condition with pause of stimulation and medication for a period of 12 h, and again after 4 h of stimulation. Comparison of these two conditions revealed activation of CMRO(2) in the cerebellum, and in specific posterior neocortical regions, most notably in the left lingual gyrus and in the right lateral occipitotemporal gyrus, both of which latter regions are linked to higher-order visual processing. CMRO(2) was unaffected in the frontal cortex. Thus, the present findings do not support the original hypothesis, but suggest that STN stimulation increases energy metabolism in the posterior cerebral cortex, especially in regions involved in perception of movement and the direction of movement to visual cues.
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Affiliation(s)
- M S Vafaee
- PET Center, Aarhus University Hospital, Aarhus, Denmark.
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30
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Peuskens H, Claeys KG, Todd JT, Norman JF, Van Hecke P, Orban GA. Attention to 3-D shape, 3-D motion, and texture in 3-D structure from motion displays. J Cogn Neurosci 2004; 16:665-82. [PMID: 15165355 DOI: 10.1162/089892904323057371] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
We used fMRI to directly compare the neural substrates of three-dimensional (3-D) shape and motion processing for realistic textured objects rotating in depth. Subjects made judgments about several different attributes of these objects, including 3-D shape, the 3-D motion, and the scale of surface texture. For all of these tasks, we equated visual input, motor output, and task difficulty, and we controlled for differences in spatial attention. Judgments about 3-D shape from motion involve both parietal and occipito-temporal regions. The processing of 3-D shape is associated with the analysis of 3-D motion in parietal regions and the analysis of surface texture in occipito-temporal regions, which is consistent with the different behavioral roles that are typically attributed to the dorsal and ventral processing streams.
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31
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Olson IR, Gatenby JC, Leung HC, Skudlarski P, Gore JC. Neuronal representation of occluded objects in the human brain. Neuropsychologia 2004; 42:95-104. [PMID: 14615079 DOI: 10.1016/s0028-3932(03)00151-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Occluding surfaces frequently obstruct the object of interest yet are easily dealt with by the visual system. Here, we test whether neural areas known to participate in motion perception and eye movements are regions that also process occluded motion. Functional magnetic resonance imaging (fMRI) was used to assess brain activation while subjects watched a moving ball become occluded. Areas activated during occluded motion included the intraparietal sulcus (IPS) as well as middle temporal (MT) regions analogous to monkey MT/MST. A second experiment showed that these results were not due to motor activity. These findings suggest that human cortical regions involved in perceiving occluded motion are similar to regions that process real motion and regions responsible for eye movements. The intraparietal sulcus may be involved in predicting the location of an unseen target for future hand or eye movements.
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Affiliation(s)
- Ingrid R Olson
- Department of Diagnostic Radiology, Yale School of Medicine, New Haven, CT 06510, USA.
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32
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David O, Cosmelli D, Hasboun D, Garnero L. A multitrial analysis for revealing significant corticocortical networks in magnetoencephalography and electroencephalography. Neuroimage 2003; 20:186-201. [PMID: 14527580 DOI: 10.1016/s1053-8119(03)00221-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We present an MEG/EEG framework to reveal statistically significant brain areas engaged in the same cognitive process across trials without resort to averaging procedures. The variability of neuronal responses is assumed to take place only in the reconstructed time series of cortical sources and not in their positions. This hypothesis allows the use of the surrogate data method to detect recurrently active brain areas across trials adjusted with any cortically constrained focal MEEG inverse solution. Results obtained from synthetic data show that considering several trials enhances the accuracy of the source localisation. We apply this approach on MEG data recorded during a simple visual stimulation. The considered stimulus is frequency tagged in order to reveal the neural network correlated to its perception using phase synchronisation analysis. The results show consistent patterns of distributed synchronous networks centred on occipital areas.
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Affiliation(s)
- Olivier David
- Cognitive Neuroscience and Brain Imaging Laboratory, CNRS UPR 640, Hôpital de La Salpêtrière, 47 bld de l'Hôpital, 75651 Paris Cedex 13, France.
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33
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d'Avossa G, Shulman GL, Corbetta M. Identification of cerebral networks by classification of the shape of BOLD responses. J Neurophysiol 2003; 90:360-71. [PMID: 12660356 DOI: 10.1152/jn.01040.2002] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Changes in regional blood oxygen level dependent (BOLD) signals in response to brief visual stimuli can exhibit a variety of time-courses. To demonstrate the anatomical distribution of BOLD response shapes during a match to sample task, a formal analysis of their time-courses is presented. An event-related design was used to estimate regional BOLD responses evoked by a cue word, which instructed the subject to attend to the motion or color of an upcoming target, and those evoked by a briefly presented moving target consisting of colored dots. Regional BOLD time-courses were adequately represented by the linear combination of three orthogonal waveforms. BOLD response shapes were then classified using a fuzzy clustering scheme. Three classes (sustained, phasic, and negative) best characterized cue responses. Four classes (sustained, sustained-phasic, phasic, and bi-phasic) best characterized target responses. In certain regions, the shape of the BOLD responses was modulated by the instruction to attend to the target's motion or color. A left frontal and a posterior parietal region showed sustained activity when motion was cued and transient activity when color was cued. A right thalamic and a left lateral occipital region showed sustained activity when color was cued and transient activity when motion was cued. Following the target several regions showed more sustained activity during motion than color trials. In summary, the effect of the task variable was focal following the cue and widespread following the target. We conclude that the temporal patterns of neural activity affected the shape of the BOLD signal.
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Affiliation(s)
- Giovanni d'Avossa
- Department of Neurology and Neurological Surgery, Alzheimer's Disease Research Center, Washington University, St. Louis, Missouri 63110, USA.
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34
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Abstract
Twenty-two nai;ve undergraduates participated in a psychophysical experiment designed to elucidate the neural events that allow us to see subtle motion differences. Half of the subjects practiced extensively on a direction-discrimination task while the other half practiced extensively on a speed-discrimination task. The stimulus conditions in the two groups were identical. The results indicated that the learning curves for direction discrimination were significantly steeper than those for speed discrimination. Additionally, the significant practice-based improvements on each motion task did not transfer to the other motion task. The different learning rates and the lack of transfer suggest that the neural events mediating speed discrimination are at least partially independent from those mediating direction discrimination, and vice versa, even under identical stimulus conditions.
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Affiliation(s)
- Tiffany Saffell
- Department of Psychology, Denison University, Granville, OH 43023, USA
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35
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Dupont P, Sáry G, Peuskens H, Orban GA. Cerebral regions processing first- and higher-order motion in an opposed-direction discrimination task. Eur J Neurosci 2003; 17:1509-17. [PMID: 12713654 DOI: 10.1046/j.1460-9568.2003.02571.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Using PET, we studied the processing of different types of motion in an opposed-direction discrimination task. We used first-order motion and two types of higher-order motion (presented as moving gratings with stripes defined by flickering texture and kinetic boundaries, respectively). In these experiments, we found that all types of motion activate a common set of cortical regions when comparing a direction discrimination task to a detection of the dimming of the fixation point. This set includes left hV3A, bilateral hMT/V5+ and regions in the middle occipital gyrus, bilateral activations in the posterior and anterior parts of the intraparietal sulcus, bilateral precentral gyrus, medial frontal cortex and regions in the cerebellum. No significant differences were observed between different types of motion, even at low statistical thresholds. From this we conclude that, under our experimental conditions, the same cerebral regions are involved in the processing of first-order and higher-order motion in an opposed-direction discrimination task.
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Affiliation(s)
- P Dupont
- K.U.Leuven, Laboratorium voor Neuro- en Psychofysiologie; Campus Gasthuisberg, B-3000 Leuven, Belgium
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36
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Fias W, Dupont P, Reynvoet B, Orban GA. The quantitative nature of a visual task differentiates between ventral and dorsal stream. J Cogn Neurosci 2002; 14:646-58. [PMID: 12126505 DOI: 10.1162/08989290260045873] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The aim of the present positron emission tomography (PET) study was to investigate how visual processing in dorsal and ventral streams depends on the quantitative nature of the task. In the same-different task, participants identified the presence of an orientation difference between two gratings, presented centrally in succession. In the quantification task, participants estimated the magnitude of the difference and compared it to a fixed standard. Detection of dimming of the fixation point was used as a control task. Visual input, motor responses, and performance were equated across tasks. Subtracting same-different from quantification yielded significant activation in the left superior parietal lobule and left ventral premotor cortex, consistent with results obtained in number-processing tasks. The reverse subtraction yielded activation in the right inferior temporal gyrus, in agreement with earlier results. These results demonstrate that a single attribute can be processed either in the ventral or dorsal stream, depending on the cognitive operations required by the tasks.
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37
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Singh KD, Barnes GR, Hillebrand A, Forde EME, Williams AL. Task-related changes in cortical synchronization are spatially coincident with the hemodynamic response. Neuroimage 2002; 16:103-14. [PMID: 11969322 DOI: 10.1006/nimg.2001.1050] [Citation(s) in RCA: 241] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Using group functional Magnetic Resonance Imaging (fMRI) and group Magnetoencephalography (MEG) we studied two cognitive paradigms: A language task involving covert letter fluency and a visual task involving biological motion direction discrimination. The MEG data were analyzed using an adaptive beam-former technique known as Synthetic Aperture Magnetometry (SAM), which provides continuous 3-D images of cortical power changes. These images were spatially normalized and averaged across subjects to provide a group SAM image in the same template space as the group fMRI data. The results show that frequency-specific, task-related changes in cortical synchronization, detected using MEG, match those areas of the brain showing an evoked cortical hemodynamic response with fMRI. The majority of these changes were event-related desynchronizations (ERDs) in the 5-10 Hz and 15-25 Hz frequency ranges. Our study demonstrates how SAM, spatial normalization, and intersubject averaging enable group MEG studies to be performed. SAM analysis also allows the MEG experiment to have exactly the same task design as the corresponding fMRI experiment. This new analysis framework represents an important advance in the use of MEG as a cognitive neuroimaging technique and also allows mutual cross-validation with fMRI.
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Affiliation(s)
- Krish D Singh
- The Wellcome Trust Laboratory for MEG Studies, Neurosciences Research Institute, Aston University, Birmingham, United Kingdom
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38
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Sterzer P, Russ MO, Preibisch C, Kleinschmidt A. Neural correlates of spontaneous direction reversals in ambiguous apparent visual motion. Neuroimage 2002; 15:908-16. [PMID: 11906231 DOI: 10.1006/nimg.2001.1030] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Looking at bistable visual stimuli, the observer experiences striking transitions between two competing percepts while the physical stimulus remains the same. Using functional imaging techniques, it is therefore possible to isolate neural correlates of perceptual changes that are independent of the low-level aspects of the stimulus. Previous experiments have demonstrated distributed activations in human extrastriate visual cortex related to switches between competing percepts. Here we asked where extrastriate responses still occur with a bistable stimulus that minimizes the cognitive difference between the two percepts. We used the "spinning wheel illusion," a bistable apparent motion stimulus of which both possible percepts correspond to the same object, share the same center, and are perceived as identically patterned stimuli moving at the same speed and changing only in direction. Using functional magnetic resonance imaging, we analyzed the spatial distribution of event-related activations occurring during spontaneous reversals of perceived direction of motion. In accordance with earlier neuroimaging findings for bistable percepts, we observed event-related activations in several frontal and parietal areas, including the superior parietal cortex bilaterally, the right inferior parietal cortex, and the premotor and inferior frontal cortex of both hemispheres. Furthermore, we found bilateral activations in the occipitotemporal junction (hMT+/V5) and in the lateral occipital sulcus ("KO") posterior to hMT+/V5, but not in areas of the "ventral stream" of cortical visual processing. Our data suggest that, while a frontoparietal network subserves more general aspects in bistable visual perception, the activations in functionally specialized extrastriate visual cortex are highly category- or attribute-specific.
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Affiliation(s)
- Philipp Sterzer
- Department of Neurology, Johann Wolfgang Goethe-University, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
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39
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Cornette L, Dupont P, Orban GA. The neural substrate of orientation short-term memory and resistance to distractor items. Eur J Neurosci 2002; 15:165-75. [PMID: 11860517 DOI: 10.1046/j.0953-816x.2001.01830.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We used Positron Emission Tomography to map the neural substrate of human short-term memory for orientation, defined as retaining a single orientation in memory over a long delay, by comparing a successive discrimination task with a 6-s delay to the same task with a brief 0.3 s delay and to an identification control task. Short-term memory engaged the superior parietal lobe bilaterally, the middle occipital gyrus bilaterally and the left dorsolateral prefrontal cortex. In addition, we studied the resistance to a distractor item by comparing the successive discrimination task with long delay, with and without an intervening distractor stimulus. This manipulative process engaged left ventral premotor cortex and left dorsolateral prefrontal cortex. The activation of left dorsolateral prefrontal cortex is interpreted as reflecting co-ordination between task components. These results, combined with those of two previous studies using an identical reduction strategy, underscore the functional heterogeneity in the prefrontal cortex during short-term and working memory.
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Affiliation(s)
- L Cornette
- Laboratorium voor Neuro- en Psychofysiologie, Katholieke Universiteit Leuven, Medical School, Campus Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium
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40
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Ptito M, Kupers R, Faubert J, Gjedde A. Cortical representation of inward and outward radial motion in man. Neuroimage 2001; 14:1409-15. [PMID: 11707096 DOI: 10.1006/nimg.2001.0947] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have used positron emission tomography to investigate the cortical areas of the normal human brain involved in processing inward (Expansion) and outward (Contraction) radial motion simulated with an optic flow stimulus. The optical flow display was made out of dots moving radially away from or toward the center of the display monitor. In the Control condition, the dots' motion was randomized in order to remove any sensation of radial motion. In the Expansion condition, several loci of activation were observed: visual areas V2-V3 and the superior parietal lobule (BA 7), predominantly in the right hemisphere. In the Contraction condition activation sites were found in the same visual areas (V2 and V3) in the right hemisphere but the increase in rCBF in these regions was much lower than in the Expansion condition. BA 7 was activated in both hemispheres. When the motion component of the stimulus was isolated by subtracting the static condition from the incoherent motion condition, we obtained activations of areas V2, V3, and MT (putative V5). These results indicate that the detection of radial motion derived from an optic flow stimulus is mediated by structures forming the dorsal part of the visual cortical system and confirm that area MT is not specifically involved in flow analysis.
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Affiliation(s)
- M Ptito
- Ecole d'Optométrie, Université de Montréal, Montréal, Quebec, Canada H3C 3J7
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41
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Benson RR, Whalen DH, Richardson M, Swainson B, Clark VP, Lai S, Liberman AM. Parametrically dissociating speech and nonspeech perception in the brain using fMRI. BRAIN AND LANGUAGE 2001; 78:364-396. [PMID: 11703063 DOI: 10.1006/brln.2001.2484] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Candidate brain regions constituting a neural network for preattentive phonetic perception were identified with fMRI and multivariate multiple regression of imaging data. Stimuli contrasted along speech/nonspeech, acoustic, or phonetic complexity (three levels each) and natural/synthetic dimensions. Seven distributed brain regions' activity correlated with speech and speech complexity dimensions, including five left-sided foci [posterior superior temporal gyrus (STG), angular gyrus, ventral occipitotemporal cortex, inferior/posterior supramarginal gyrus, and middle frontal gyrus (MFG)] and two right-sided foci (posterior STG and anterior insula). Only the left MFG discriminated natural and synthetic speech. The data also supported a parallel rather than serial model of auditory speech and nonspeech perception.
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Affiliation(s)
- R R Benson
- Department of Neurology, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT 06030-2017, USA.
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42
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Abstract
Observer motion in a stationary visual environment results in an optic flow pattern on the retina, which in simple situations can be used to determine the direction of self motion or heading. The present study, using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), investigated the human cerebral activation pattern, elicited when subjects viewing a ground plane optic flow pattern actively judged heading. Several successive experiments controlled for visual input, visuospatial attention, and motor response effects. Results indicate that the network specifically involved in heading consists of only two motion sensitive areas: human MT/V5+, including an inferior satellite, and dorsal intraparietal sulcus area (DIPSM/L), predominantly in the right hemisphere, plus a dorsal premotor region bilaterally. These results suggest possible homologies with the dorsal part of the medial superior temporal area and area 7a in the monkey.
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43
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Faillenot I, Sunaert S, Van Hecke P, Orban GA. Orientation discrimination of objects and gratings compared: an fMRI study. Eur J Neurosci 2001; 13:585-96. [PMID: 11168567 DOI: 10.1046/j.1460-9568.2001.01399.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We used functional magnetic resonance imaging to compare the human brain regions involved in orientation discrimination of two-dimensional (2D) objects and gratings. The orientation discrimination tasks, identification and successive discrimination, were contrasted to a dimming detection control condition with identical retinal input. Regions involved in orientation discrimination were very similar for the two types of tasks and for the two types of stimuli and both belonged to the dorsal and ventral visual pathways. They included posterior occipital, lingual, posterior fusiform, inferior temporal, dorsal intraparietal and medial parietal regions. The main difference between the two types of stimuli was a larger activation of precuneus when 2D objects were used compared to gratings. The main difference between discrimination tasks was an enhanced activity, at the group level, in superior frontal sulcus in identification compared to successive discrimination, and at least at the single subject level, a larger activity in right fusiform cortex in successive discriminations compared to identification. Thus, in contradiction to generally accepted views, orientation discrimination of gratings and objects involve largely similar networks including both ventral and dorsal visual regions.
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Affiliation(s)
- I Faillenot
- K.U. Leuven, Faculty of Medicine, Lab. Neuro- en Psychofysiologie, Campus Gasthuisberg, B-3000 Leuven, Belgium
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44
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Abstract
Functional imaging in humans reveals the interplay of the many components of the human visual system: how they process the various types of information contained in the image to recover characteristics of the three-dimensional world surrounding us, but also how, in the course of this process, the retinal image is gradually integrated with non-retinal signals to provide information about the outside world in a format useful to other non-visual brain regions.
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Affiliation(s)
- G A Orban
- K.U. Leuven, School of Medicine, Laboratorium voor Neuro- en Psychofysiologie, Campus Gasthuisberg, B-3000 Leuven, Belgium.
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45
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Cornette L, Dupont P, Bormans G, Mortelmans L, Orban GA. Separate neural correlates for the mnemonic components of successive discrimination and working memory tasks. Cereb Cortex 2001; 11:59-72. [PMID: 11113035 DOI: 10.1093/cercor/11.1.59] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have used positron emission tomography to map the mnemonic components of two tasks at the extremes of the visual short-term/ working memory spectrum. The successive discrimination task requires only storage of a single item for very short time (ultra-short- term memory), while the 2back task requires both maintenance (i.e. storage and rehearsal) and manipulation of several items (working memory). We tested whether or not the storage component, common to the two tasks, engaged the same cerebral regions. To remove unnecessary confounds, we reduced the cues available to the subjects to a single elementary attribute, the orientation of a grating presented in central vision. This prevented subjects from using verbal strategies or vestibular cues and allowed equating of difficulty among tasks. Ultra-short-term memory for orientation engaged a large expanse of occipito-temporal cortex with a rate-dependent antero-posterior gradient: a fast trial rate engaged posterior regions, a slow trial rate anterior regions. On the other hand, working memory for orientation involved the left inferior parietal cortex, left dorsolateral prefrontal cortex and a left superior frontal sulcus region, and to a lesser degree the symmetrical right superior frontal region and a left superior parietal region. Direct comparison of the two orientation memory networks confirmed their functional segregation. We conclude that at least the storage of orientation information engages distinct regions depending on whether or not short-term memory/working memory involves rehearsal and/or manipulative processes.
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Affiliation(s)
- L Cornette
- Laboratorium voor Neuro- en Psychofysiologie, KU Leuven, Medical School, Campus Gasthuisberg, Herestraat 49, B-3000 Leuven
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46
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de Zubicaray GI, Andrew C, Zelaya FO, Williams SC, Dumanoir C. Motor response suppression and the prepotent tendency to respond: a parametric fMRI study. Neuropsychologia 2000; 38:1280-91. [PMID: 10865104 DOI: 10.1016/s0028-3932(00)00033-6] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the present study we utilised functional magnetic resonance imaging (fMRI) to examine cerebral activation during performance of a classic motor task in which response suppression load was parametrically varied. Linear increases in activity were observed in a distributed network of regions across both cerebral hemispheres, although with more extensive involvement of the right prefrontal cortex. Activated regions included prefrontal, parietal and occipitotemporal cortices. Decreasing activation was similarly observed in a distributed network of regions. These response forms are discussed in terms of an increasing requirement for visual cue discrimination and suppression/selection of motor responses, and a decreasing probability of the occurrence of non-target stimuli and attenuation of a prepotent tendency to respond. The results support recent proposals for a dominant role for the right-hemisphere in performance of motor response suppression tasks that emphasise the importance of the right prefrontal cortex.
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Affiliation(s)
- G I de Zubicaray
- Centre for Magnetic Resonance, The University of Queensland, QLD 4072, Australia.
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47
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Abstract
It has been claimed that the visual brain is organized in two separate processing streams for spatial vision: one for perception and one for action. To determine whether motion vision is also divided into vision for action and for perception we examined the interceptive behaviour of the motion-blind patient LM. The task for LM and three age-matched control subjects was to reach-and-grasp for an object that moved away. Three experiments were conducted to examine the effects on perfomance of target speed (Expt 1), observation time (Expt 2) and visual feedback (Expt 3). As LM is only able to reach for objects which move at 0.5 m/s or less, her performance is inferior to that of controls who can reach for objects moving at 1.0 m/s, but it is better than would be expected from her performance in psychophysical experiments on her motion vision. Kinematic analysis of LM's reaching movements showed that she adapted the speed of her moving hand to the speed of the target but only when full vision was available. In contrast to normal subjects, LM required long observation times and vision of her moving hand to produce successful reaching responses. Thus, the impairment of both perception and action in LM suggests that the motion area MT/V5 is located at an early stage of the extrastriate hierarchy and provides input to both the perception and the action processing streams.
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Affiliation(s)
- T Schenk
- Neurologische Klinik, Klinikum Grosshadern, Ludwig-Maximilians-Universität München, Marchioninistr. 23, 81366 Germany.
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48
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Abstract
We performed a series of experiments to quantify the effects of task performance on cortical activity in early visual areas. Functional magnetic resonance imaging (fMRI) was used to measure cortical activity in several cortical visual areas including primary visual cortex (V1) and the MT complex (MT+) as subjects performed a variety of threshold-level visual psychophysical tasks. Performing speed, direction, and contrast discrimination tasks produced strong modulations of cortical activity. For example, one experiment tested for selective modulations of MT+ activity as subjects alternated between performing contrast and speed discrimination tasks. MT+ responses modulated in phase with the periods of time during which subjects performed the speed discrimination task; that is, MT+ activity was higher during speed discrimination than during contrast discrimination. Task-related modulations were consistent across repeated measurements in each subject; however, significant individual differences were observed between subjects. Together, the results suggest 1) that specific changes in the cognitive/behavioral state of a subject can exert selective and reliable modulations of cortical activity in early visual cortex, even in V1; 2) that there are significant individual differences in these modulations; and 3) that visual areas and pathways that are highly sensitive to small changes in a given stimulus feature (such as contrast or speed) are selectively modulated during discrimination judgments on that feature. Increasing the gain of the relevant neuronal signals in this way may improve their signal-to-noise to help optimize task performance.
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Affiliation(s)
- A C Huk
- Department of Psychology, Stanford University, Stanford, California 94305-2130, USA
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49
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Sunaert S, Van Hecke P, Marchal G, Orban GA. Attention to speed of motion, speed discrimination, and task difficulty: an fMRI study. Neuroimage 2000; 11:612-23. [PMID: 10860790 DOI: 10.1006/nimg.2000.0587] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We studied the functional neuroanatomy of attention to speed of motion using functional magnetic resonance imaging in eight healthy subjects, who performed a speed discrimination (SID) task using a random textured pattern moving at a reference speed of 6 deg/s. During the control condition (DIM), with retinal stimulation identical to that during SID, subjects detected the dimming of the central fixation point. Attention to speed (SID compared to DIM) activated mainly ventral V3 and V4, dorsal V3 and V3A. Compared to a fixation control condition, speed discrimination recruited a large visuomotor network, including hMT/V5+. However, hMT/V5+ was only marginally more active during speed discrimination than during dimming detection. Thus hMT/V5+ is involved in speed discrimination, in line with the speed discrimination impairments following hMT/V5+ lesions, but our results suggest that this activity simply reflects the processing of motion rather than attention to speed. Manipulating the difficulty of the speed discrimination task over a large range of the psychometric curve revealed that increasing difficulty linearly increases activity in right frontal regions, as well as in lateral occipital and dorsal parietal regions. A weak effect of difficulty was also observed in dorsal V3.
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Affiliation(s)
- S Sunaert
- Afdeling Radiologie, UZ Gasthuisberg, Leuven, B-3000, Belgium
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50
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Abstract
Psychophysical studies of the short-term memory for attributes or dimensions of the visual stimulus that are known to be important in early visual processing (spatial frequency, orientation, contrast, motion and color) identify a low-level perceptual memory mechanism. This proposed mechanism is located early in the visual processing stream, prior to the structural description system responsible for shape priming but beyond primary visual cortex (V1); it is composed of a series of parallel, special-purpose perceptual mechanisms with independent but limited processing resources. Each mechanism is devoted to the analysis of a single dimension and is coupled to a memory store.
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Affiliation(s)
- S Magnussen
- Dept of Psychology, University of Oslo, Norway
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