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Chou BC, Lerner A, Barisano G, Phung D, Xu W, Pinto SN, Sheikh-Bahaei N. Functional MRI and Diffusion Tensor Imaging in Migraine: A Review of Migraine Functional and White Matter Microstructural Changes. J Cent Nerv Syst Dis 2023; 15:11795735231205413. [PMID: 37900908 PMCID: PMC10612465 DOI: 10.1177/11795735231205413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 09/14/2023] [Indexed: 10/31/2023] Open
Abstract
Migraine is a complex and heterogenous disorder whose disease mechanisms remain disputed. This narrative review summarizes functional MRI (fMRI) and diffusion tensor imaging (DTI) findings and interprets their association with migraine symptoms and subtype to support and expand our current understanding of migraine pathophysiology. Our PubMed search evaluated and included fMRI and DTI studies involving comparisons between migraineurs vs healthy controls, migraineurs with vs without aura, and episodic vs chronic migraineurs. Migraineurs demonstrate changes in functional connectivity (FC) and regional activation in numerous pain-related networks depending on migraine phase, presence of aura, and chronicity. Changes to diffusion indices are observed in major cortical white matter tracts extending to the brainstem and cerebellum, more prominent in chronic migraine and associated with FC changes. Reported changes in FC and regional activation likely relate to pain processing and sensory hypersensitivities. Diffuse white matter microstructural changes in dysfunctional cortical pain and sensory pathways complement these functional differences. Interpretations of reported fMRI and DTI measure trends have not achieved a clear consensus due to inconsistencies in the migraine neuroimaging literature. Future fMRI and DTI studies should establish and implement a uniform methodology that reproduces existing results and directly compares migraineurs with different subtypes. Combined fMRI and DTI imaging may provide better pathophysiological explanations for nonspecific FC and white matter microstructural differences.
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Affiliation(s)
- Brendon C. Chou
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Alexander Lerner
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | | | - Daniel Phung
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Wilson Xu
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Soniya N. Pinto
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Nasim Sheikh-Bahaei
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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Kam KY, Chang DHF. Sensory eye dominance plasticity in the human adult visual cortex. Front Neurosci 2023; 17:1250493. [PMID: 37746154 PMCID: PMC10513037 DOI: 10.3389/fnins.2023.1250493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 08/17/2023] [Indexed: 09/26/2023] Open
Abstract
Sensory eye dominance occurs when the visual cortex weighs one eye's data more heavily than those of the other. Encouragingly, mechanisms underlying sensory eye dominance in human adults retain a certain degree of plasticity. Notably, perceptual training using dichoptically presented motion signal-noise stimuli has been shown to elicit changes in sensory eye dominance both in visually impaired and normal observers. However, the neural mechanisms underlying these learning-driven improvements are not well understood. Here, we measured changes in fMRI responses before and after a five-day visual training protocol to determine the neuroplastic changes along the visual cascade. Fifty visually normal observers received training on a dichoptic or binocular variant of a signal-in-noise (left-right) motion discrimination task over five consecutive days. We show significant shifts in sensory eye dominance following training, but only for those who received dichoptic training. Pattern analysis of fMRI responses revealed that responses of V1 and hMT+ predicted sensory eye dominance for both groups, but only before training. After dichoptic (but not binocular) visual training, responses of V1 changed significantly, and were no longer able to predict sensory eye dominance. Our data suggest that perceptual training-driven changes in eye dominance are driven by a reweighting of the two eyes' data in the primary visual cortex. These findings may provide insight into developing region-targeted rehabilitative paradigms for the visually impaired, particularly those with severe binocular imbalance.
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Affiliation(s)
- Ka Yee Kam
- Department of Psychology, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Dorita H. F. Chang
- Department of Psychology, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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Nagysomkuti Mertse N, Müri R. Case Report: SMART ANTON: Anton-Babinski Syndrome in Stroke-Like Migraine Attacks (SMART) After Radiation Therapy: Two Rare Syndromes, One Case. Front Neurol 2022; 13:887287. [PMID: 35832180 PMCID: PMC9271741 DOI: 10.3389/fneur.2022.887287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 05/16/2022] [Indexed: 11/17/2022] Open
Abstract
Introduction We describe the case of a 57-years-old patient who presented an Anton-Babinski syndrome in the context of a stroke-like migraine attack after radiation therapy (SMART). Case Report The patient was brought to the emergency room following a sudden loss of vision in the context of a pre-existing left-sided hemianopia after excision of a right occipital astrocytoma followed by radio-chemotherapy 35 years prior to his admission in our services. At admittance, he also presented hyperthermia, hypertension, and a GCS of 7. The MRI showed a leptomeningeal enhancement in the left temporal, parietal, and occipital lobes. After exclusion of other differential diagnoses, we diagnosed a cortical blindness in the context of a SMART syndrome affecting the left hemisphere. While the symptoms improved under corticosteroid therapy, the patient successively presented an Anton-Babinski syndrome, a Riddoch syndrome and a visual associative agnosia before finally regaining his usual sight. Discussion This is, to our knowledge, the first report of an Anton-Babinski syndrome in the context of a SMART syndrome. A dual etiology is mandatory for cortical blindness in SMART syndrome since the latter affects only one hemisphere. A SMART syndrome affecting the contralateral hemisphere in respect to the radiation site seems to be uncommon, which makes this case even more exceptional.
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Affiliation(s)
- Nicolas Nagysomkuti Mertse
- Department of Neurology, University Hospital Bern, Bern, Switzerland
- Department of Psychiatry, University Hospital of Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
- Translational Research Center, University Hospital of Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
- *Correspondence: Nicolas Nagysomkuti Mertse
| | - René Müri
- Department of Neurology, University Hospital Bern, Bern, Switzerland
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Liu X, Huang H, Snutch TP, Cao P, Wang L, Wang F. The Superior Colliculus: Cell Types, Connectivity, and Behavior. Neurosci Bull 2022; 38:1519-1540. [PMID: 35484472 DOI: 10.1007/s12264-022-00858-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 02/16/2022] [Indexed: 10/18/2022] Open
Abstract
The superior colliculus (SC), one of the most well-characterized midbrain sensorimotor structures where visual, auditory, and somatosensory information are integrated to initiate motor commands, is highly conserved across vertebrate evolution. Moreover, cell-type-specific SC neurons integrate afferent signals within local networks to generate defined output related to innate and cognitive behaviors. This review focuses on the recent progress in understanding of phenotypic diversity amongst SC neurons and their intrinsic circuits and long-projection targets. We further describe relevant neural circuits and specific cell types in relation to behavioral outputs and cognitive functions. The systematic delineation of SC organization, cell types, and neural connections is further put into context across species as these depend upon laminar architecture. Moreover, we focus on SC neural circuitry involving saccadic eye movement, and cognitive and innate behaviors. Overall, the review provides insight into SC functioning and represents a basis for further understanding of the pathology associated with SC dysfunction.
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Affiliation(s)
- Xue Liu
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, the Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hongren Huang
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, the Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Terrance P Snutch
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, V6T 1Z4, Canada
| | - Peng Cao
- National Institute of Biological Sciences, Beijing, 100049, China
| | - Liping Wang
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, the Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China.
| | - Feng Wang
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, the Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China.
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A methodological scoping review of the integration of fMRI to guide dMRI tractography. What has been done and what can be improved: A 20-year perspective. J Neurosci Methods 2022; 367:109435. [PMID: 34915047 DOI: 10.1016/j.jneumeth.2021.109435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 11/23/2022]
Abstract
Combining MRI modalities is a growing trend in neurosciences. It provides opportunities to investigate the brain architecture supporting cognitive functions. Integrating fMRI activation to guide dMRI tractography offers potential advantages over standard tractography methods. A quick glimpse of the literature on this topic reveals that this technique is challenging, and no consensus or "best practices" currently exist, at least not within a single document. We present the first attempt to systematically analyze and summarize the literature of 80 studies that integrated task-based fMRI results to guide tractography, over the last two decades. We report 19 findings that cover challenges related to sample size, microstructure modelling, seeding methods, multimodal space registration, false negatives/positives, specificity/validity, gray/white matter interface and more. These findings will help the scientific community (1) understand the strengths and limitations of the approaches, (2) design studies using this integrative framework, and (3) motivate researchers to fill the gaps identified. We provide references toward best practices, in order to improve the overall result's replicability, sensitivity, specificity, and validity.
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Danckert J, Striemer C, Rossetti Y. Blindsight. HANDBOOK OF CLINICAL NEUROLOGY 2021; 178:297-310. [PMID: 33832682 DOI: 10.1016/b978-0-12-821377-3.00016-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
For over a century, research has demonstrated that damage to primary visual cortex does not eliminate all capacity for visual processing in the brain. From Riddoch's (1917) early demonstration of intact motion processing for blind field stimuli, to the iconic work of Weiskrantz et al. (1974) showing reliable spatial localization, it is clear that secondary visual pathways that bypass V1 carry information to the visual brain that in turn influences behavior. In this chapter, we briefly outline the history and phenomena associated with blindsight, before discussing the nature of the secondary visual pathways that support residual visual processing in the absence of V1. We finish with some speculation as to the functional characteristics of these secondary pathways.
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Affiliation(s)
- James Danckert
- Department of Psychology, University of Waterloo, Waterloo, ON, Canada.
| | | | - Yves Rossetti
- Trajectoires, Centre de Recherche en Neurosciences de Lyon, Inserm, CNRS, Université Lyon 1, Bron, France; Plateforme "Mouvement et Handicap", Hôpital Henry-Gabrielle, Hospices Civils de Lyon, Saint-Genis-Laval, France
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7
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Assessing motor, visual and language function using a single 5-minute fMRI paradigm: three birds with one stone. Brain Imaging Behav 2019; 12:1775-1785. [PMID: 29480439 DOI: 10.1007/s11682-018-9848-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Clinical functional Magnetic Resonance Imaging (fMRI) requires inferences on localization of major brain functions at the individual subject level. We hypothesized that a single "triple use" task would satisfy sensitivity and reliability requirements for successfully assessing the motor, visual and language domain in this context. This was tested here by the application in a group of healthy adults, assessing sensitivity and reliability at the individual subject level, separately for each domain.Our "triple use" task consisted of 2 conditions (condition 1, assessing motor and visual domain, and condition 2, assessing the language domain), serving mutually as active/control. We included 20 healthy adult subjects. Random effect analyses showed activation in primary motor, visual and language regions, as expected. Less expected regions were activated both for the motor and visual domains. Further, reliability of primary activation patterns was very high across individual subjects, with activation seen in 70-100% of subjects in primary motor, visual, and left-lateralized language regions.These findings suggest the "triple use" task to be reliable at the individual subject's level to assess motor, visual and language domains in the clinical fMRI context. Benefits of such an approach include shortening of acquisition time, simplicity of the task for each domain, and using a visual stimulus. Following establishment of reliability in adults, the task may also be a valuable addition in the pediatric clinical fMRI context, where each of these factors is of high relevance.
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Heutink J, de Haan G, Marsman JB, van Dijk M, Cordes C. The effect of target speed on perception of visual motion direction in a patient with akinetopsia. Cortex 2019; 119:511-518. [PMID: 30661737 DOI: 10.1016/j.cortex.2018.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 10/09/2018] [Accepted: 12/06/2018] [Indexed: 11/26/2022]
Abstract
Although much research has been devoted to the neural correlates of motion perception, the processing of speed of motion is still a topic of discussion. Apart from patient LM, no in-depth clinical research has been done in the past 20 years on this topic. In the present study, we investigated patient TD, who suffered from the rare disorder akinetopsia due to bilateral lesions of V5 after stroke. By means of a Random-Dot-Kinematogram (RDK) in which speed was varied systematically, it was found that TD was impaired in perceiving the direction of movement at speeds exceeding 9 deg/s. Our study suggests that V5 plays an important role in processing high-speed visual motion and further implies that V5 does not play a crucial role in processing low-speed visual motion. A remarkable finding, which has not been shown before, was that TD always reported the opposite direction of the actual movement at a speed of 24 deg/s. This suggests a form of the continuous wagon wheel illusion, which might have been caused by intact brain areas operating at different sampling rates than area V5.
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Affiliation(s)
- Joost Heutink
- Department of Clinical and Developmental Neuropsychology, University of Groningen, Groningen, the Netherlands; Royal Dutch Visio, Centre of Expertise for Visually Impaired and Blind People, Department of Knowledge, Expertise & Innovation, Huizen, the Netherlands.
| | - Gera de Haan
- Department of Clinical and Developmental Neuropsychology, University of Groningen, Groningen, the Netherlands; Royal Dutch Visio, Centre of Expertise for Visually Impaired and Blind People, Rehabilitation & Advice, Leeuwarden, the Netherlands
| | - Jan-Bernard Marsman
- Cognitive Neuroscience Center, Biomedical Sciences of Cells and Systems, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Mart van Dijk
- Research School of Behavioural and Cognitive Neurosciences, University of Groningen, Groningen, the Netherlands
| | - Christina Cordes
- Department of Clinical and Developmental Neuropsychology, University of Groningen, Groningen, the Netherlands; Royal Dutch Visio, Centre of Expertise for Visually Impaired and Blind People, Department of Knowledge, Expertise & Innovation, Huizen, the Netherlands
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9
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Jan JE, Heaven RKB, Matsuba C, Langley MB, Roman-Lantzy C, Anthony TL. Windows into the Visual Brain: New Discoveries about the Visual System, Its Functions, and Implications for Practitioners. JOURNAL OF VISUAL IMPAIRMENT & BLINDNESS 2019. [DOI: 10.1177/0145482x1310700402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Introduction In recent years, major progress has been made in understanding the human visual system because of new investigative techniques. These developments often contradict older concepts about visual function. Methods A detailed literature search and interprofessional discussions. Results Recent innovative neurological tests are described that are able to show much more accurately the visual pathways, the process of vision, and the close relationships among sensory modalities. These tests also reveal the remarkable neuroplasticity of the human brain and disorders of connectivity that frequently involve visual function. Discussion How these recent neurological advances may benefit service providers is discussed. Implications for practitioners It is important that from time to time new neurological and ophthalmic developments are summarized for professionals who are involved in the clinical management of individuals with visual disorders and how the newly acquired knowledge affects the diagnosis and intervention strategies. Visual rehabilitation must be based on up-to-date science, which continually changes and grows with research.
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Affiliation(s)
- James E. Jan
- Pediatric Neurology, Department of Neurophysiology, University of British Columbia, BC Children Hospital, 4480 Oak Street, Vancouver, BC, V6H3V4, Canada
| | - Roberta K. B. Heaven
- Department of Psychiatry, University of British Columbia, and team leader, Visual Impairment Program, BC Children's Hospital and Sunny Hill Hospital for Children, 3644 Slocan Street, Vancouver, BC, V5M, 3E8, Canada
| | - Carey Matsuba
- Visual Impairment Program, Department of Pediatrics, University of British Columbia, and pediatric consultant, Visual Impairment Program, BC Children's Hospital, 4480 Oak Street, Vancouver, BC, V6H 3V4, Canada
| | - M. Beth Langley
- Pre-kindergarten Assessment Team, Pinellas County Schools, 301 Fourth Street SW, Largo, FL 33770
| | - Christine Roman-Lantzy
- Western Pennsylvania Hospital, 4800 Friendship Avenue, Pittsburgh, PA 15224; CVI project leader, American Printing House for the Blind; and special assistant to the superintendent, Western Pennsylvania School for the Blind
| | - Tanni L. Anthony
- Exceptional Student Services Unit, Colorado Department of Education, 1560 Broadway, Suite 1175, Denver, CO 80202
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Grasso PA, Làdavas E, Bertini C, Caltabiano S, Thut G, Morand S. Decoupling of Early V5 Motion Processing from Visual Awareness: A Matter of Velocity as Revealed by Transcranial Magnetic Stimulation. J Cogn Neurosci 2018; 30:1517-1531. [DOI: 10.1162/jocn_a_01298] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Motion information can reach V5/MT through two parallel routes: one conveying information at early latencies through a direct subcortical route and the other reaching V5 later via recurrent projections through V1. Here, we tested the hypothesis that input via the faster direct pathway depends on motion characteristics. To this end, we presented motion stimuli to healthy human observers at different velocities (4.4°/sec vs. 23°/sec) with static stimuli as controls while applying transcranial magnetic stimulation (TMS) pulses over V5 or V1. We probed for TMS interference with objective (two-alternative forced choice [2AFC]) and subjective (awareness) measures of motion processing at six TMS delays from stimulus onset (poststimulus window covered: ∼27–160 msec). Our results for V5–TMS showed earlier interference with objective performance for fast motion (53.3 msec) than slow motion (80 msec) stimuli. Importantly, TMS-induced decreases in objective measures of motion processing did correlate with decreases in subjective measures for slow but not fast motion stimuli. Moreover, V1–TMS induced a temporally unspecific interference with visual processing as it impaired the processing of both motion and static stimuli at the same delays. These results are in accordance with fast moving stimuli reaching V5 through a different route than slow moving stimuli. The differential latencies and coupling to awareness suggest distinct involvement of a direct (i.e., colliculo-extrastriate) connection bypassing V1 depending on stimulus velocity (fast vs. slow). Implication of a direct pathway in the early processing of fast motion may have evolved through its behavioral relevance.
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11
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Erskine D, Thomas AJ, Taylor JP, Savage MA, Attems J, McKeith IG, Morris CM, Khundakar AA. Neuronal Loss and Α-Synuclein Pathology in the Superior Colliculus and Its Relationship to Visual Hallucinations in Dementia with Lewy Bodies. Am J Geriatr Psychiatry 2017; 25:595-604. [PMID: 28190674 DOI: 10.1016/j.jagp.2017.01.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 01/05/2017] [Accepted: 01/06/2017] [Indexed: 01/16/2023]
Abstract
OBJECTIVE Patients with dementia with Lewy bodies (DLB) often experience visual hallucinations, which are related to decreased quality of life for patients and increased caregiver distress. The pathologic changes that contribute to visual hallucinations are not known, but several hypotheses implicate deficient attentional processing. The superior colliculus has a role in visual attention and planning eye movements and has been directly implicated in several models of visual hallucinations. Therefore, the present study sought to identify neurodegenerative changes that may contribute to hallucinations in DLB. METHODS Postmortem superior colliculus tissue from 13 comparison, 10 DLB, and 10 Alzheimer disease (AD) cases was evaluated using quantitative neuropathologic methods. RESULTS α-Synuclein and tau deposition were more severe in deeper layers of the superior colliculus. DLB cases had neuronal density reductions in the stratum griseum intermedium, an important structure in directing attention toward visual targets. In contrast, neuronal density was reduced in all laminae of the superior colliculus in AD. CONCLUSION These findings suggest that regions involved in directing attention toward visual targets are subject to neurodegenerative changes in DLB. Considering several hypotheses of visual hallucinations implicating dysfunctional attention toward external stimuli, these findings may provide evidence of pathologic changes that contribute to the manifestation of visual hallucinations in DLB.
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Affiliation(s)
- Daniel Erskine
- Ageing Research Laboratories, Newcastle University, Newcastle upon Tyne, United Kingdom; Medical Toxicology Centre, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Alan J Thomas
- Biomedical Research Building, Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - John-Paul Taylor
- Biomedical Research Building, Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Michael A Savage
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Johannes Attems
- Ageing Research Laboratories, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Ian G McKeith
- Biomedical Research Building, Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Christopher M Morris
- Ageing Research Laboratories, Newcastle University, Newcastle upon Tyne, United Kingdom; Medical Toxicology Centre, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Ahmad A Khundakar
- Ageing Research Laboratories, Newcastle University, Newcastle upon Tyne, United Kingdom.
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12
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Simultaneity judgment using olfactory-visual, visual-gustatory, and olfactory-gustatory combinations. PLoS One 2017; 12:e0174958. [PMID: 28376116 PMCID: PMC5380340 DOI: 10.1371/journal.pone.0174958] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 03/17/2017] [Indexed: 11/19/2022] Open
Abstract
Vision is a physical sense, whereas olfaction and gustation are chemical senses. Active sensing might function in vision, olfaction, and gustation, whereas passive sensing might function in vision and olfaction but not gustation. To investigate whether each sensory property affected synchrony perception, participants in this study performed simultaneity judgment (SJ) for three cross-modal combinations using visual (red LED light), olfactory (coumarin), and gustatory (NaCl solution) stimuli. We calculated the half-width at half-height (HWHH) and point of subjective simultaneity (PSS) on the basis of temporal distributions of simultaneous response rates in each combination. Although HWHH did not differ significantly among three cross-modal combinations, HWHH exhibited a higher value in cross-modal combinations involving one or two chemical stimuli than in combinations of two physical stimuli, reported in a previous study. The PSS of the olfactory–visual combination was approximately equal to the point of objective simultaneity (POS), whereas the PSS of visual–gustatory, and olfactory–gustatory combinations receded significantly from the POS. In order to generalize these results as specific to chemical senses in regard to synchrony perception, we need to determine whether the same phenomena will be reproduced when performing SJ for various cross-modal combinations using visual, olfactory, and gustatory stimuli other than red LED light, coumarin, and NaCl solution.
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13
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Hervais-Adelman A, Legrand LB, Zhan M, Tamietto M, de Gelder B, Pegna AJ. Looming sensitive cortical regions without V1 input: evidence from a patient with bilateral cortical blindness. Front Integr Neurosci 2015; 9:51. [PMID: 26557059 PMCID: PMC4614319 DOI: 10.3389/fnint.2015.00051] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 09/25/2015] [Indexed: 11/26/2022] Open
Abstract
Fast and automatic behavioral responses are required to avoid collision with an approaching stimulus. Accordingly, looming stimuli have been found to be highly salient and efficient attractors of attention due to the implication of potential collision and potential threat. Here, we address the question of whether looming motion is processed in the absence of any functional primary visual cortex and consequently without awareness. For this, we investigated a patient (TN) suffering from complete, bilateral damage to his primary visual cortex. Using an fMRI paradigm, we measured TN's brain activation during the presentation of looming, receding, rotating, and static point lights, of which he was unaware. When contrasted with other conditions, looming was found to produce bilateral activation of the middle temporal areas, as well as the superior temporal sulcus and inferior parietal lobe (IPL). The latter are generally thought to be involved in multisensory processing of motion in extrapersonal space, as well as attentional capture and saliency. No activity was found close to the lesioned V1 area. This demonstrates that looming motion is processed in the absence of awareness through direct subcortical projections to areas involved in multisensory processing of motion and saliency that bypass V1.
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Affiliation(s)
- Alexis Hervais-Adelman
- Laboratory of Experimental Neuropsychology, Neurology Clinic, Department of Clinical Neuroscience, University of Geneva Geneva, Switzerland ; Brain and Language Lab, Department of Clinical Neuroscience, University of Geneva Geneva, Switzerland
| | - Lore B Legrand
- Laboratory of Experimental Neuropsychology, Neurology Clinic, Department of Clinical Neuroscience, University of Geneva Geneva, Switzerland ; Faculty of Psychology and Educational Sciences, University of Geneva Geneva, Switzerland
| | - Minye Zhan
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands
| | - Marco Tamietto
- Department of Psychology, University of Torino Torino, Italy ; Cognitive and Affective Neuroscience Laboratory, Center of Research on Psychology in Somatic Diseases, Tilburg University Tilburg, Netherlands ; Department of Experimental Psychology, University of Oxford Oxford, UK
| | - Beatrice de Gelder
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands
| | - Alan J Pegna
- Laboratory of Experimental Neuropsychology, Neurology Clinic, Department of Clinical Neuroscience, University of Geneva Geneva, Switzerland ; Faculty of Psychology and Educational Sciences, University of Geneva Geneva, Switzerland ; School of Psychology, University of Queensland Brisbane, QLD, Australia
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Altered white matter in early visual pathways of humans with amblyopia. Vision Res 2015; 114:48-55. [PMID: 25615840 DOI: 10.1016/j.visres.2014.12.021] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 12/16/2014] [Accepted: 12/17/2014] [Indexed: 11/23/2022]
Abstract
Amblyopia is a visual disorder caused by poorly coordinated binocular input during development. Little is known about the impact of amblyopia on the white matter within the visual system. We studied the properties of six major visual white-matter pathways in a group of adults with amblyopia (n=10) and matched controls (n=10) using diffusion weighted imaging (DWI) and fiber tractography. While we did not find significant differences in diffusion properties in cortico-cortical pathways, patients with amblyopia exhibited increased mean diffusivity in thalamo-cortical visual pathways. These findings suggest that amblyopia may systematically alter the white matter properties of early visual pathways.
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Gaglianese A, Costagli M, Ueno K, Ricciardi E, Bernardi G, Pietrini P, Cheng K. The direct, not V1-mediated, functional influence between the thalamus and middle temporal complex in the human brain is modulated by the speed of visual motion. Neuroscience 2015; 284:833-844. [DOI: 10.1016/j.neuroscience.2014.10.042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 09/26/2014] [Accepted: 10/24/2014] [Indexed: 10/24/2022]
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Barleben M, Stoppel CM, Kaufmann J, Merkel C, Wecke T, Goertler M, Heinze HJ, Hopf JM, Schoenfeld MA. Neural correlates of visual motion processing without awareness in patients with striate cortex and pulvinar lesions. Hum Brain Mapp 2014; 36:1585-94. [PMID: 25529748 DOI: 10.1002/hbm.22725] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 11/21/2014] [Accepted: 12/08/2014] [Indexed: 11/11/2022] Open
Abstract
Patients with striate cortex lesions experience visual perception loss in the contralateral visual field. In few patients, however, stimuli within the blind field can lead to unconscious (blindsight) or even conscious perception when the stimuli are moving (Riddoch syndrome). Using functional magnetic resonance imaging (fMRI), we investigated the neural responses elicited by motion stimulation in the sighted and blind visual fields of eight patients with lesions of the striate cortex. Importantly, repeated testing ensured that none of the patients exhibited blindsight or a Riddoch syndrome. Three patients had additional lesions in the ipsilesional pulvinar. For blind visual field stimulation, great care was given that the moving stimulus was precisely presented within the borders of the scotoma. In six of eight patients, the stimulation within the scotoma elicited hemodynamic activity in area human middle temporal (hMT) while no activity was observed within the ipsilateral lesioned area of the striate cortex. One of the two patients in whom no ipsilesional activity was observed had an extensive lesion including massive subcortical damage. The other patient had an additional focal lesion within the lateral inferior pulvinar. Fiber-tracking based on anatomical and functional markers (hMT and Pulvinar) on individual diffusion tensor imaging (DTI) data from each patient revealed the structural integrity of subcortical pathways in all but the patient with the extensive subcortical lesion. These results provide clear evidence for the robustness of direct subcortical pathways from the pulvinar to area hMT in patients with striate cortex lesions and demonstrate that ipsilesional activity in area hMT is completely independent of conscious perception.
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Affiliation(s)
- Maria Barleben
- Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany
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Kellmeyer P, Ziegler W, Peschke C, Juliane E, Schnell S, Baumgaertner A, Weiller C, Saur D. Fronto-parietal dorsal and ventral pathways in the context of different linguistic manipulations. BRAIN AND LANGUAGE 2013; 127:241-250. [PMID: 24183468 DOI: 10.1016/j.bandl.2013.09.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 08/20/2013] [Accepted: 09/30/2013] [Indexed: 06/02/2023]
Abstract
This study investigates structural connectivity between left fronto-parietal brain regions that were identified in a previous fMRI study which used different linguistic manipulation tasks. Diffusion-weighted images were acquired from 20 volunteers. Structural connectivity between brain regions from the fMRI study was computed using probabilistic fiber tracking. For suprasegmental manipulation, left inferior parietal lobule (IPL) and left inferior frontal gyrus (IFG), pars opercularis, were connected by a dorsal pathway via the arcuate fascicle and superior longitudinal fascicle III. For segmental manipulation, left IPL and IFG, pars triangularis, were connected by a ventral pathway via the middle longitudinal fascicle and the extreme capsule. We conclude that the dorsal pathway provides a route for mapping from phonological memory in IPL to the inferior frontal articulatory network while the ventral pathway could facilitate the modulation of phonological units based on lexical-semantic aspects, mediate the complexity of auditory objects and the unification of actor-event schemata.
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Affiliation(s)
- Philipp Kellmeyer
- Department of Neurology, University Medical Center Freiburg, Breisacher Str. 64, D-70196 Freiburg, Germany; Freiburg Brain Imaging, University Medical Center Freiburg, Breisacher Str. 64, D-79106 Freiburg, Germany.
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Bennett IJ, Rypma B. Advances in functional neuroanatomy: a review of combined DTI and fMRI studies in healthy younger and older adults. Neurosci Biobehav Rev 2013; 37:1201-10. [PMID: 23628742 DOI: 10.1016/j.neubiorev.2013.04.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 04/09/2013] [Accepted: 04/17/2013] [Indexed: 11/30/2022]
Abstract
Structural connections between brain regions are thought to influence neural processing within those regions. It follows that alterations to the quality of structural connections should influence the magnitude of neural activity. The quality of structural connections may also be expected to differentially influence activity in directly versus indirectly connected brain regions. To test these predictions, we reviewed studies that combined diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) in younger and older adults. By surveying studies that examined relationships between DTI measures of white matter integrity and fMRI measures of neural activity, we identified variables that accounted for variability in these relationships. Results revealed that relationships between white matter integrity and neural activity varied with (1) aging (i.e., positive and negative DTI-fMRI relationships in younger and older adults, respectively) and (2) spatial proximity of the neural measures (i.e., positive and negative DTI-fMRI relationships when neural measures were extracted from adjacent and non-adjacent brain regions, respectively). Together, the studies reviewed here provided support for both of our predictions.
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Affiliation(s)
- Ilana J Bennett
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX 75235, USA.
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Seemungal BM, Guzman-Lopez J, Arshad Q, Schultz SR, Walsh V, Yousif N. Vestibular activation differentially modulates human early visual cortex and V5/MT excitability and response entropy. Cereb Cortex 2013; 23:12-9. [PMID: 22291031 PMCID: PMC3513948 DOI: 10.1093/cercor/bhr366] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Head movement imposes the additional burdens on the visual system of maintaining visual acuity and determining the origin of retinal image motion (i.e., self-motion vs. object-motion). Although maintaining visual acuity during self-motion is effected by minimizing retinal slip via the brainstem vestibular-ocular reflex, higher order visuovestibular mechanisms also contribute. Disambiguating self-motion versus object-motion also invokes higher order mechanisms, and a cortical visuovestibular reciprocal antagonism is propounded. Hence, one prediction is of a vestibular modulation of visual cortical excitability and indirect measures have variously suggested none, focal or global effects of activation or suppression in human visual cortex. Using transcranial magnetic stimulation-induced phosphenes to probe cortical excitability, we observed decreased V5/MT excitability versus increased early visual cortex (EVC) excitability, during vestibular activation. In order to exclude nonspecific effects (e.g., arousal) on cortical excitability, response specificity was assessed using information theory, specifically response entropy. Vestibular activation significantly modulated phosphene response entropy for V5/MT but not EVC, implying a specific vestibular effect on V5/MT responses. This is the first demonstration that vestibular activation modulates human visual cortex excitability. Furthermore, using information theory, not previously used in phosphene response analysis, we could distinguish between a specific vestibular modulation of V5/MT excitability from a nonspecific effect at EVC.
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Affiliation(s)
- Barry M Seemungal
- Centre for Neurosciences, Charing Cross Campus, Imperial College London, London W6 8RF, UK.
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Wildenberg JC, Tyler ME, Danilov YP, Kaczmarek KA, Meyerand ME. Altered connectivity of the balance processing network after tongue stimulation in balance-impaired individuals. Brain Connect 2013; 3:87-97. [PMID: 23216162 PMCID: PMC3621359 DOI: 10.1089/brain.2012.0123] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Some individuals with balance impairment have hypersensitivity of the motion-sensitive visual cortices (hMT+) compared to healthy controls. Previous work showed that electrical tongue stimulation can reduce the exaggerated postural sway induced by optic flow in this subject population and decrease the hypersensitive response of hMT+. Additionally, a region within the brainstem (BS), likely containing the vestibular and trigeminal nuclei, showed increased optic flow-induced activity after tongue stimulation. The aim of this study was to understand how the modulation induced by tongue stimulation affects the balance-processing network as a whole and how modulation of BS structures can influence cortical activity. Four volumes of interest, discovered in a general linear model analysis, constitute major contributors to the balance-processing network. These regions were entered into a dynamic causal modeling analysis to map the network and measure any connection or topology changes due to the stimulation. Balance-impaired individuals had downregulated response of the primary visual cortex (V1) to visual stimuli but upregulated modulation of the connection between V1 and hMT+ by visual motion compared to healthy controls (p ≤ 1E-5). This upregulation was decreased to near-normal levels after stimulation. Additionally, the region within the BS showed increased response to visual motion after stimulation compared to both prestimulation and controls. Stimulation to the tongue enters the central nervous system at the BS but likely propagates to the cortex through supramodal information transfer. We present a model to explain these brain responses that utilizes an anatomically present, but functionally dormant pathway of information flow within the processing network.
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Affiliation(s)
- Joe C Wildenberg
- Neuroscience Training Program, University of Wisconsin, Madison, Wisconsin 53705, USA.
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Gaglianese A, Costagli M, Bernardi G, Ricciardi E, Pietrini P. Evidence of a direct influence between the thalamus and hMT+ independent of V1 in the human brain as measured by fMRI. Neuroimage 2012; 60:1440-7. [PMID: 22300813 DOI: 10.1016/j.neuroimage.2012.01.093] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 01/13/2012] [Accepted: 01/17/2012] [Indexed: 11/28/2022] Open
Abstract
In the present study we employed Conditional Granger Causality (CGC) and Coherence analysis to investigate whether visual motion-related information reaches the human middle temporal complex (hMT+) directly from the Lateral Geniculate Nucleus (LGN) of the thalamus, by-passing the primary visual cortex (V1). Ten healthy human volunteers underwent brain scan examinations by functional magnetic resonance imaging (fMRI) during two optic flow experiments. In addition to the classical LGN-V1-hMT+ pathway, our results showed a significant direct influence of the blood oxygenation level dependent (BOLD) signal recorded in LGN over that in hMT+, not mediated by V1 activity, which strongly supports the existence of a bilateral pathway that connects LGN directly to hMT+ and serves visual motion processing. Furthermore, we evaluated the relative latencies among areas functionally connected in the processing of visual motion. Using LGN as a reference region, hMT+ exhibited a statistically significant earlier peak of activation as compared to V1. In conclusion, our findings suggest the co-existence of an alternative route that directly links LGN to hMT+, bypassing V1. This direct pathway may play a significant functional role for the faster detection of motion and may contribute to explain persistence of unconscious motion detection in individuals with severe destruction of primary visual cortex (blindsight).
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Affiliation(s)
- Anna Gaglianese
- Laboratory of Clinical Biochemistry and Molecular Biology, University of Pisa Medical School, Pisa, Italy
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Wildenberg JC, Tyler ME, Danilov YP, Kaczmarek KA, Meyerand ME. Electrical tongue stimulation normalizes activity within the motion-sensitive brain network in balance-impaired subjects as revealed by group independent component analysis. Brain Connect 2011; 1:255-65. [PMID: 22433053 DOI: 10.1089/brain.2011.0029] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Multivariate analysis of functional magnetic resonance imaging (fMRI) data allows investigations into network behavior beyond simple activations of individual regions. We apply group independent component analysis to fMRI data collected in a previous study looking at the sustained neuromodulatory effects of electrical tongue stimulation in balance-impaired individuals. Twelve subjects with balance disorders viewed optic flow in an fMRI scanner before and after 5 days of electrical tongue stimulation. Nine healthy controls also viewed the visual stimuli but did not receive any stimulation. Multiple regression of the 47 estimated components found two that were modulated by the visual stimuli. Component 7, comprised primarily of the primary visual cortex (V1), responded to all visual stimuli and showed no difference in task-related activity between the healthy controls and the balance-impaired subjects before or after stimulation. Component 11 responded only to motion in the visual field and contained multiple cortical and subcortical regions involved in processing information pertinent to balance. Two-sample t-tests of the calculated signal change revealed that the task-related activity of this network is greater in balance-impaired subjects compared with controls before stimulation (p=0.02), but that this network hypersensitivity decreases after electrical tongue stimulation (p=0.001).
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Affiliation(s)
- Joseph C Wildenberg
- Neuroscience Training Program, University of Wisconsin, Madison, Wisconsin 53705, USA.
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Anderson EJ, Jones DK, O'Gorman RL, Leemans A, Catani M, Husain M. Cortical network for gaze control in humans revealed using multimodal MRI. Cereb Cortex 2011; 22:765-75. [PMID: 21693784 PMCID: PMC3306571 DOI: 10.1093/cercor/bhr110] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) techniques allow definition of cortical nodes that are presumed to be components of large-scale distributed brain networks involved in cognitive processes. However, very few investigations examine whether such functionally defined areas are in fact structurally connected. Here, we used combined fMRI and diffusion MRI-based tractography to define the cortical network involved in saccadic eye movement control in humans. The results of this multimodal imaging approach demonstrate white matter pathways connecting the frontal eye fields and supplementary eye fields, consistent with the known connectivity of these regions in macaque monkeys. Importantly, however, these connections appeared to be more prominent in the right hemisphere of humans. In addition, there was evidence of a dorsal frontoparietal pathway connecting the frontal eye field and the inferior parietal lobe, also right hemisphere dominant, consistent with specialization of the right hemisphere for directed attention in humans. These findings demonstrate the utility and potential of using multimodal imaging techniques to define large-scale distributed brain networks, including those that demonstrate known hemispheric asymmetries in humans.
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Soria G, De Notaris M, Tudela R, Blasco G, Puig J, Planas AM, Pedraza S, Prats-Galino A. Improved Assessment of Ex Vivo Brainstem Neuroanatomy With High-Resolution MRI and DTI at 7 Tesla. Anat Rec (Hoboken) 2011; 294:1035-44. [DOI: 10.1002/ar.21383] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Accepted: 02/15/2011] [Indexed: 11/07/2022]
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Abstract
PURPOSE OF REVIEW Both monkey and human neuroimaging studies show that visual processing beyond the striate cortex involves a highly complex network of regions with modular functions. Lesions within this network lead to specific clinical syndromes. In this review we discuss studies on blindsight, which is the ability of remaining regions to support vision in the absence of striate cortex or visual awareness, recent work on 'ventral stream' syndromes such as object agnosia, alexia, prosopagnosia, and topographagnosia, which follow damage to medial occipitotemporal structures, and simultanagnosia, the classic 'dorsal stream' deficit related to bilateral occipitoparietal lesions. RECENT FINDINGS We highlight work on the anatomic basis of blindsight, the recent description of the new disorder developmental topographic disorientation, and studies contrasting global and local perception in simultanagnosia. SUMMARY These studies advance our understanding of the mechanisms of complex visual processing and provide an important neuropsychological complement to our expanding knowledge about vision from functional neuroimaging.
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Converging Evidence for the Advantage of Dynamic Facial Expressions. Brain Topogr 2011; 24:149-63. [DOI: 10.1007/s10548-011-0171-4] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 02/10/2011] [Indexed: 11/26/2022]
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Jobst BC, Williamson PD, Thadani VM, Gilbert KL, Holmes GL, Morse RP, Darcey TM, Duhaime AC, Bujarski KA, Roberts DW. Intractable occipital lobe epilepsy: clinical characteristics and surgical treatment. Epilepsia 2011; 51:2334-7. [PMID: 20662891 DOI: 10.1111/j.1528-1167.2010.02673.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Intractable occipital lobe epilepsy remains a surgical challenge. Clinical characteristics of 14 patients were analyzed. Twelve patients had surgery, seven patients had visual auras (50%) and only eight patients (57%) had posterior scalp EEG changes. Ictal single-proton emission computed tomography (SPECT) incorrectly localized in 7 of 10 patients. Six patients (50%) had Engel's class I outcome. Patients with inferior occipital seizure onset appeared to fare better (three of four class I) than patients with lateral or medial occipital seizure onset (three of eight class I). Patients who had all three occipital surfaces covered with electrodes had a better outcome (four of five class I) than patients who had limited electroencephalography (EEG) coverage (two of seven class I). Magnetic resonance imaging (MRI) lesions did not guarantee a seizure free outcome. In conclusion, visual auras, scalp EEG, and imaging findings are not reliable for correct identification of occipital onset. Occipital seizure onset can be easily missed in nonlesional epilepsy. Comprehensive intracranial EEG coverage of all three occipital surfaces leads to better outcomes.
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Affiliation(s)
- Barbara C Jobst
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA.
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Reply: Operculo-insular pain (parasylvian pain): a distinct central pain syndrome * Not all that glisters is gold--nor all that responds a primary sensory area. Brain 2010. [DOI: 10.1093/brain/awq309] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Istoc A, Habas C, Iba-Zizen MT, Nguyen T, Abanou A, Yoshida M, Bellinger L, Le Gargasson JF, Cabanis E. Intérêt de la neurotractographie fonctionnelle dans la reconstruction des voies visuelles en IRMTD. J Fr Ophtalmol 2010; 33:670-9. [DOI: 10.1016/j.jfo.2010.09.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Accepted: 09/08/2010] [Indexed: 10/18/2022]
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Naggara O, Létourneau-Guillon L, Mellerio C, Belair M, Pruvo JP, Leclerc X, Meder JF, Oppenheim C. [Diffusion-weighted MR imaging of the brain]. JOURNAL DE RADIOLOGIE 2010; 91:329-49; quiz 350-1. [PMID: 20508569 DOI: 10.1016/s0221-0363(10)70050-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Imaging of water diffusion or diffusion-weighted MR imaging provides physiological information about brain diseases that cannot be obtained from conventional sequences. This technique is very sensitive for the detection of cerebral ischemia from arterial origin and can distinguish cerebral ischemia from other non-vascular brain pathologies in patients presenting with abrupt onset of focal neurological deficit. Diffusion-weighted imaging is used for the evaluation of non-vascular diseases as well. Combined with conventional sequences, it is helpful to differentiate brain abscesses from necrotic tumors. Quantitative diffusion-weighted imaging provides additional information in the characterization of tumors or inflammatory, degenerative and metabolic lesions. Finally, diffusion-weighted imaging data also has prognostic value.
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Affiliation(s)
- O Naggara
- Unité de Recherche en Neuroradiologie Interventionnelle, Département de Radiologie, Centre hospitalier de l'Université de Montréal, Hôpital Notre-Dame, Montréal, Canada.
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Leube DT, Knoblich G, Erb M, Schlotterbeck P, Kircher TTJ. The neural basis of disturbed efference copy mechanism in patients with schizophrenia. Cogn Neurosci 2010; 1:111-7. [PMID: 24168277 DOI: 10.1080/17588921003646156] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Core psychopathological symptoms in patients with schizophrenia suggest that their sense of self may be disturbed. A disturbance in predictive motor mechanisms may be the cause of such symptoms. Ten patients with schizophrenia and ten healthy right-handed control subjects opened and closed their hand. This movement was filmed with an MRI compatible video camera and projected online onto a monitor. BOLD contrast was measured with fMRI. The temporal delay between movement and feedback was parametrically varied. Participants judged whether or not there was a delay. Patients were less sensitive to these delays than a matched control group. Comparing neural activation between the two groups showed a reduced attenuation of movement-sensitive perceptual areas in patients with increasing delay and a higher activation in the putamen in controls. The results provide further evidence that impaired efference copy mechanisms may contribute to the pathogenesis of schizophrenia and its first rank symptoms.
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