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Immature excitatory neurons in the amygdala come of age during puberty. Dev Cogn Neurosci 2022; 56:101133. [PMID: 35841648 PMCID: PMC9289873 DOI: 10.1016/j.dcn.2022.101133] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 06/23/2022] [Accepted: 07/08/2022] [Indexed: 11/21/2022] Open
Abstract
The human amygdala is critical for emotional learning, valence coding, and complex social interactions, all of which mature throughout childhood, puberty, and adolescence. Across these ages, the amygdala paralaminar nucleus (PL) undergoes significant structural changes including increased numbers of mature neurons. The PL contains a large population of immature excitatory neurons at birth, some of which may continue to be born from local progenitors. These progenitors disappear rapidly in infancy, but the immature neurons persist throughout childhood and adolescent ages, indicating that they develop on a protracted timeline. Many of these late-maturing neurons settle locally within the PL, though a small subset appear to migrate into neighboring amygdala subnuclei. Despite its prominent growth during postnatal life and possible contributions to multiple amygdala circuits, the function of the PL remains unknown. PL maturation occurs predominately during late childhood and into puberty when sex hormone levels change. Sex hormones can promote developmental processes such as neuron migration, dendritic outgrowth, and synaptic plasticity, which appear to be ongoing in late-maturing PL neurons. Collectively, we describe how the growth of late-maturing neurons occurs in the right time and place to be relevant for amygdala functions and neuropsychiatric conditions.
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2
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Akeret K, Forkel SJ, Buzzi RM, Vasella F, Amrein I, Colacicco G, Serra C, Krayenbühl N. Multimodal anatomy of the human forniceal commissure. Commun Biol 2022; 5:742. [PMID: 35879431 PMCID: PMC9314404 DOI: 10.1038/s42003-022-03692-3] [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: 12/21/2021] [Accepted: 07/07/2022] [Indexed: 11/25/2022] Open
Abstract
Ambiguity surrounds the existence and morphology of the human forniceal commissure. We combine advanced in-vivo tractography, multidirectional ex-vivo fiber dissection, and multiplanar histological analysis to characterize this structure’s anatomy. Across all 178 subjects, in-vivo fiber dissection based on the Human Connectome Project 7 T MRI data identifies no interhemispheric connections between the crura fornicis. Multidirectional ex-vivo fiber dissection under the operating microscope demonstrates the psalterium as a thin soft-tissue membrane spanning between the right and left crus fornicis, but exposes no commissural fibers. Multiplanar histological analysis with myelin and Bielchowsky silver staining, however, visualizes delicate cruciform fibers extending between the crura fornicis, enclosed by connective tissue, the psalterium. The human forniceal commissure is therefore much more delicate than previously described and presented in anatomical textbooks. This finding is consistent with the observed phylogenetic trend of a reduction of the forniceal commissure in non-human primates compared to non-primate eutherian mammals. Anatomical dissection and tractography elucidate the delicate nature of the human forniceal commissure, an interhemispheric white matter circuit.
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Affiliation(s)
- Kevin Akeret
- Department of Neurosurgery, Clinical Neuroscience Center, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Stephanie J Forkel
- Brain Connectivity and Behaviour Laboratory, Sorbonne Universities, Paris, France.,Donders Centre for Cognition, Radboud University, Thomas van Aquinostraat 4, 6525 GD, Nijmegen, the Netherlands.,Centre for Neuroimaging Sciences, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,Departments of Neurosurgery, Technical University of Munich School of Medicine, Munich, Germany
| | - Raphael M Buzzi
- Division of Internal Medicine, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Flavio Vasella
- Department of Neurosurgery, Clinical Neuroscience Center, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Irmgard Amrein
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Department of Health Sciences and Technology, ETH, Zurich, Switzerland
| | | | - Carlo Serra
- Department of Neurosurgery, Clinical Neuroscience Center, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Niklaus Krayenbühl
- Department of Neurosurgery, Clinical Neuroscience Center, University Hospital Zurich and University of Zurich, Zurich, Switzerland. .,Division of Pediatric Neurosurgery, University Children's Hospital, Zurich, Switzerland.
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3
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Hardi FA, Goetschius LG, Peckins MK, Brooks-Gunn J, McLanahan SS, McLoyd V, Lopez-Duran NL, Mitchell C, Hyde LW, Monk CS. Differential Developmental Associations of Material Hardship Exposure and Adolescent Amygdala-Prefrontal Cortex White Matter Connectivity. J Cogn Neurosci 2021; 34:1866-1891. [PMID: 34942644 PMCID: PMC9651170 DOI: 10.1162/jocn_a_01801] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Accumulating literature has linked poverty to brain structure and function, particularly in affective neural regions; however, few studies have examined associations with structural connections or the importance of developmental timing of exposure. Moreover, prior neuroimaging studies have not used a proximal measure of poverty (i.e., material hardship, which assesses food, housing, and medical insecurity) to capture the lived experience of growing up in harsh economic conditions. The present investigation addressed these gaps collectively by examining the associations between material hardship (ages 1, 3, 5, 9, and 15 years) and white matter connectivity of frontolimbic structures (age of 15 years) in a low-income sample. We applied probabilistic tractography to diffusion imaging data collected from 194 adolescents. Results showed that material hardship related to amygdala-prefrontal, but not hippocampus-prefrontal or hippocampus-amygdala, white matter connectivity. Specifically, hardship during middle childhood (ages 5 and 9 years) was associated with greater connectivity between the amygdala and dorsomedial pFC, whereas hardship during adolescence (age of 15 years) was related to reduced amygdala-orbitofrontal (OFC) and greater amygdala-subgenual ACC connectivity. Growth curve analyses showed that greater increases of hardship across time were associated with both greater (amygdala-subgenual ACC) and reduced (amygdala-OFC) white matter connectivity. Furthermore, these effects remained above and beyond other types of adversity, and greater hardship and decreased amygdala-OFC connectivity were related to increased anxiety and depressive symptoms. Results demonstrate that the associations between material hardship and white matter connections differ across key prefrontal regions and developmental periods, providing support for potential windows of plasticity for structural circuits that support emotion processing.
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4
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Wei L, Wu GR, Bi M, Baeken C. Effective connectivity predicts cognitive empathy in cocaine addiction: a spectral dynamic causal modeling study. Brain Imaging Behav 2021; 15:1553-1561. [PMID: 32710329 DOI: 10.1007/s11682-020-00354-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Social cognition plays a crucial role in the development and treatment of cocaine dependence. However, studies investigating social cognition, such as empathy and its underlying neural basis, are lacking. To explore the neural interactions among reward and memory circuits, we applied effective connectivity analysis on resting-state fMRI data collected from cocaine-dependent subjects. The relationship between effective connectivity within these two important circuits and empathy ability - evaluated with the Interpersonal Reactivity Index (IRI) - was assessed by machine learning algorithm using multivariate regression analysis. In accordance with the neurocircuitry disruptions of cocaine addiction, the results showed that cocaine-dependent subjects relative to healthy controls had altered resting state effective connectivity between parts of the memory and reward systems. Furthermore, effective connectivity between the memory and reward system could predict the fantasy empathy (FE) subscale scores in cocaine dependence. Overall, our findings provide further evidence for the neural substrates of social cognition in cocaine-dependent patients. These new insights could be useful for the development of new treatment programs for this substance dependency disorder.
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Affiliation(s)
- Luqing Wei
- School of Psychology, Jiangxi Normal University, Nanchang, China
| | - Guo-Rong Wu
- Key Laboratory of Cognition and Personality, Faculty of Psychology, Southwest University, Chongqing, China. .,Ghent Experimental Psychiatry (GHEP) Lab, Ghent University, Ghent, Belgium.
| | - Minghua Bi
- Key Laboratory of Cognition and Personality, Faculty of Psychology, Southwest University, Chongqing, China
| | - Chris Baeken
- Ghent Experimental Psychiatry (GHEP) Lab, Ghent University, Ghent, Belgium.,Department of Psychiatry and Medical Psychology, Ghent University, Ghent, Belgium.,Department of Psychiatry, Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZBrussel), Laarbeeklaan 101, 1090, Brussels, Belgium.,Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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5
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Celiker Uslu S, Yuksel B, Tekin B, Sariahmetoglu H, Atakli D. Cognitive impairment and drug responsiveness in mesial temporal lobe epilepsy. Epilepsy Behav 2019; 90:162-167. [PMID: 30576963 DOI: 10.1016/j.yebeh.2018.10.034] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 10/17/2018] [Accepted: 10/24/2018] [Indexed: 10/27/2022]
Abstract
OBJECTIVES Mesial temporal lobe epilepsy (MTLE) is the most common form of partial epilepsies. Seizures of MTLE with hippocampal sclerosis (MTLE-HS) are typically resistant to antiepileptic drug (AED) therapy. Although memory disturbances in patients with MTLE-HS are expected, verbal attention and frontal lobe functions may also be impaired. We aimed to examine the relationship between the clinical features and cognitive functions of patients by comparing cognitive test scores of patients with MTLE with few seizures (drug-responsive group) and those with frequent seizures (pharmacoresistant group). METHODS Seventy-nine patients with MTLE-HS and 30 healthy controls were enrolled. Thirty-four patients were accepted as the drug-responsive group (DrG), and 45 patients were included in the pharmacoresistant group (PRG). Tests evaluating attention, memory, and executive functions were performed on all participants. RESULTS Forty-nine (62%) female and 30 (38%) male patients with MTLE-HS, and 14 (46.7%) female and 16 (53.3%) male controls participated in the study. The mean age of the patients and controls was 33.53 ± 9.60 (range, 18-57) years and 35.90 ± 7.98 (range, 18-56) years, respectively. Both the DrG and PRG showed poorer performances in tests evaluating memory and frontal lobe functions when compared with the control group (CG). Additionally, attention test results were significantly worse in the PRG than in the DrG. CONCLUSION It is reasonable to say that increased seizure frequency is the main causative factor of verbal attention deficit due to the poorer attention test results in the PRG. Poor performances in memory and frontal lobe function tests of all patients with MTLE-HS emphasized the importance of the mutual connection between the temporal lobe and prefrontal cortices.
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Affiliation(s)
- Sibel Celiker Uslu
- Samsun Training and Research Hospital Neurology Department, İlkadım, 55090 Samsun, Turkey
| | - Burcu Yuksel
- Antalya Training and Research Hospital, Neurology Department, Muratpasa, 07050 Antalya, Turkey.
| | - Betul Tekin
- Rumeli Hospital Neurology Department, Kucukcekmece, 34295 Istanbul, Turkey
| | - Hande Sariahmetoglu
- Bakirkoy Training and Research Hospital for Psychiatry, Neurology and Neurosurgery, Neurology Department, Bakirkoy, 34147 Istanbul, Turkey
| | - Dilek Atakli
- Bakirkoy Training and Research Hospital for Psychiatry, Neurology and Neurosurgery, Neurology Department, Bakirkoy, 34147 Istanbul, Turkey
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Kamali A, Riascos RF, Pillai JJ, Sair HI, Patel R, Nelson FM, Lincoln JA, Tandon N, Mirbagheri S, Rabiei P, Keser Z, Hasan KM. Mapping the trajectory of the amygdalothalamic tract in the human brain. J Neurosci Res 2018; 96:1176-1185. [PMID: 29607550 DOI: 10.1002/jnr.24235] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Revised: 03/01/2018] [Accepted: 03/02/2018] [Indexed: 11/11/2022]
Abstract
Although the thalamus is not considered primarily as a limbic structure, abundant evidence indicates the essential role of the thalamus as a modulator of limbic functions indirectly through the amygdala. The amygdala is a central component of the limbic system and serves an essential role in modulating the core processes including the memory, decision-making, and emotional reactions. The amygdalothalamic pathway is the largest direct amygdalo-diencephalic connection in the primates including the human brain. Given the crucial role of the amygdalothalamic tract (ATT) in memory function and diencephalic amnesia in stroke patients, diffusion tensor imaging may be helpful in better visualizing the surgical anatomy of this pathway noninvasively. To date, few diffusion-weighted studies have focused on the amygdala, yet the fine neuronal connection of the amygdala and thalamus known as the ATT has yet to be elucidated. This study aimed to investigate the utility of high spatial resolution diffusion tensor tractography for mapping the trajectory of the ATT in the human brain. We studied 15 healthy right-handed human subjects (12 men and 3 women with age range of 24-37 years old). Using a high-resolution diffusion tensor tractography technique, for the first time, we were able to reconstruct and measure the trajectory of the ATT. We further revealed the close relationship of the ATT with the temporopontine tract and the fornix bilaterally in 15 healthy adult human brains.
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Affiliation(s)
- Arash Kamali
- Departments of Diagnostic Radiology, University of Texas at Houston, Houston, Texas, USA
| | - Roy F Riascos
- Departments of Diagnostic Radiology, University of Texas at Houston, Houston, Texas, USA
| | - Jay J Pillai
- Department of Diagnostic Radiology, Division of Neuroradiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Haris I Sair
- Department of Diagnostic Radiology, Division of Neuroradiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Rajan Patel
- Departments of Diagnostic Radiology, University of Texas at Houston, Houston, Texas, USA
| | - Flavia M Nelson
- Department of Neurology, University of Texas at Houston, Houston, Texas, USA
| | - John A Lincoln
- Department of Neurology, University of Texas at Houston, Houston, Texas, USA
| | - Nitin Tandon
- Department of Neurosurgery, University of Texas at Houston, Houston, Texas, USA
| | - Saeedeh Mirbagheri
- Department of Diagnostic Radiology, Mount Saini Beth Israel, New York, New York, USA
| | - Pejman Rabiei
- Departments of Diagnostic Radiology, University of Texas at Houston, Houston, Texas, USA
| | - Zafer Keser
- Department of Neurology, University of Texas at Houston, Houston, Texas, USA
| | - Khader M Hasan
- Departments of Diagnostic Radiology, University of Texas at Houston, Houston, Texas, USA
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7
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Dorfer C, Czech T, Aull-Watschinger S, Baumgartner C, Jung R, Kasprian G, Novak K, Pirker S, Seidl B, Stefanits H, Trimmel K, Pataraia E. Mesial temporal lobe epilepsy: long-term seizure outcome of patients primarily treated with transsylvian selective amygdalohippocampectomy. J Neurosurg 2017; 129:174-181. [PMID: 29027855 DOI: 10.3171/2017.4.jns162699] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The aim of this study was to present long-term seizure outcome data in a consecutive series of patients with refractory mesial temporal lobe epilepsy primarily treated with transsylvian selective amygdalohippocampectomy (SAHE). METHODS The authors retrospectively analyzed prospectively collected data for all patients who had undergone resective surgery for medically refractory epilepsy at their institution between July 1994 and December 2014. Seizure outcome was assessed according to the International League Against Epilepsy (ILAE) and the Engel classifications. RESULTS The authors performed an SAHE in 158 patients (78 males, 80 females; 73 right side, 85 left side) with a mean age of 37.1 ± 10.0 years at surgery. Four patients lost to follow-up and 1 patient who committed suicide were excluded from analysis. The mean follow-up period was 9.7 years. At the last available follow-up (or before reoperation), 68 patients (44.4%) had achieved an outcome classified as ILAE Class 1a, 46 patients (30.1%) Class 1, 6 patients (3.9%) Class 2, 16 patients (10.4%) Class 3, 15 patients (9.8%) Class 4, and 2 patients (1.3%) Class 5. These outcomes correspond to Engel Class I in 78.4% of the patients, Engel Class II in 10.5%, Engel Class III in 8.5%, and Engel Class IV in 2.0%. Eleven patients underwent a second surgery (anterior temporal lobectomy) after a mean of 4.4 years from the SAHE (left side in 6 patients, right side in 5). Eight (72.7%) of these 11 patients achieved seizure freedom. The overall ILEA seizure outcome since (re)operation after a mean follow-up of 10.0 years was Class 1a in 72 patients (47.0%), Class 1 in 50 patients (32.6%), Class 2 in 7 patients (4.6%), Class 3 in 15 patients (9.8%), Class 4 in 8 patients (5.2%), and Class 5 in 1 patient (0.6%). These outcomes correspond to an Engel Class I outcome in 84.3% of the patients. CONCLUSIONS A satisfactory long-term seizure outcome following transsylvian SAHE was demonstrated in a selected group of patients with refractory temporal lobe epilepsy.
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Affiliation(s)
| | | | | | - Christoph Baumgartner
- 3Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, General Hospital Hietzing with Neurological Center Rosenhügel, Vienna, Austria
| | | | - Gregor Kasprian
- 4Radiology and Nuclear Medicine, Medical University of Vienna; and
| | | | - Susanne Pirker
- 3Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, General Hospital Hietzing with Neurological Center Rosenhügel, Vienna, Austria
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8
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Hakamata Y, Komi S, Moriguchi Y, Izawa S, Motomura Y, Sato E, Mizukami S, Kim Y, Hanakawa T, Inoue Y, Tagaya H. Amygdala-centred functional connectivity affects daily cortisol concentrations: a putative link with anxiety. Sci Rep 2017; 7:8313. [PMID: 28814810 PMCID: PMC5559590 DOI: 10.1038/s41598-017-08918-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 07/13/2017] [Indexed: 12/11/2022] Open
Abstract
The amygdala plays a critical role in emotion. Its functional coupling with the hippocampus and ventromedial prefrontal cortex extending to a portion of the anterior cingulate cortex (ACC) is implicated in anxiogenesis and hypothalamic-pituitary-adrenal (HPA) system regulation. However, it remains unclear how amygdala-centred functional connectivity (FC) affects anxiety and cortisol concentrations in everyday life. Here, we investigate the relationship between daily cortisol concentrations (dCOR) and amygdala-centred FC during emotional processing in forty-one healthy humans. FC analyses revealed that higher dCOR predicted strengthened amygdala-centred FC with the hippocampus and cerebellum, but inhibited FC with the supramarginal gyrus and a perigenual part of the ACC (pgACC) when processing fearful faces (vs. neutral faces). Notably, the strength of amygdala-hippocampus FC mediated the positive relationship between cortisol and anxiety, specifically when the effect of amygdala-pgACC FC, a presumptive neural indicator of emotional control, was taken into account. Individuals with diminished connectivity between the amygdala and pgACC during fear-related processing might be more vulnerable to anxiogenesis as it pertains to greater circulating cortisol levels in everyday life. Individual functional patterns of amygdala-hippocampal-pgACC connectivity might provide a key to understand the complicate link between cortisol and anxiety-related behaviors.
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Affiliation(s)
- Yuko Hakamata
- Department of Adult Mental Health, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan. .,Department of Health Sciences, Kitasato University School of Allied Health Sciences, Kanagawa, Japan.
| | - Shotaro Komi
- Department of Radiology, Kitasato University Hospital, Kanagawa, Japan
| | - Yoshiya Moriguchi
- Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Shuhei Izawa
- Occupational Stress Research Group, National Institute of Occupational Safety and Health, Kanagawa, Japan
| | - Yuki Motomura
- Department of Psychophysiology, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Eisuke Sato
- Department of Medical Radiological Technology, Kyorin University School of Health Sciences, Tokyo, Japan
| | - Shinya Mizukami
- Department of Clinical Engineering, Kitasato University School of Allied Health Sciences, Kanagawa, Japan
| | - Yoshiharu Kim
- Department of Adult Mental Health, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Takashi Hanakawa
- Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Yusuke Inoue
- Department of Diagnostic Radiology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Hirokuni Tagaya
- Department of Health Sciences, Kitasato University School of Allied Health Sciences, Kanagawa, Japan
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Sivakanthan S, Neal E, Murtagh R, Vale FL. The evolving utility of diffusion tensor tractography in the surgical management of temporal lobe epilepsy: a review. Acta Neurochir (Wien) 2016; 158:2185-2193. [PMID: 27566714 DOI: 10.1007/s00701-016-2910-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/27/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND Diffusion tensor imaging (DTI) is a relatively new imaging modality that has found many peri-operative applications in neurosurgery. METHODS A comprehensive survey of the applications of diffusion tensor imaging (DTI) in planning for temporal lobe epilepsy surgery was conducted. The presentation of this literature is supplemented by a case illustration. RESULTS The authors have found that DTI is well utilized in epilepsy surgery, primarily in the tractography of Meyer's loop. DTI has also been used to demonstrate extratemporal connections that may be responsible for surgical failure as well as perioperative planning. The tractographic anatomy of the temporal lobe is discussed and presented with original DTI pictures. CONCLUSIONS The uses of DTI in epilepsy surgery are varied and rapidly evolving. A discussion of the technology, its limitations, and its applications is well warranted and presented in this article.
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Affiliation(s)
- Sananthan Sivakanthan
- Department of Neurosurgery and Brain Repair, University of South Florida, Morsani College of Medicine, 2 Tampa General Circle, 7th Floor, Tampa, FL, 33606, USA.
| | - Elliot Neal
- Department of Neurosurgery and Brain Repair, University of South Florida, Morsani College of Medicine, 2 Tampa General Circle, 7th Floor, Tampa, FL, 33606, USA
- Brainlab Inc, Westchester, IL, USA
| | - Ryan Murtagh
- Department of Radiology, University of South Florida, Morsani College of Medicine, Tampa, FL, USA
| | - Fernando L Vale
- Department of Neurosurgery and Brain Repair, University of South Florida, Morsani College of Medicine, 2 Tampa General Circle, 7th Floor, Tampa, FL, 33606, USA
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10
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Aubert S, Bonini F, Curot J, Valton L, Szurhaj W, Derambure P, Rheims S, Ryvlin P, Wendling F, McGonigal A, Trébuchon A, Bartolomei F. The role of sub-hippocampal versus hippocampal regions in bitemporal lobe epilepsies. Clin Neurophysiol 2016; 127:2992-2999. [DOI: 10.1016/j.clinph.2016.06.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 06/18/2016] [Accepted: 06/21/2016] [Indexed: 11/27/2022]
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11
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Lai X, Ren J, Lu Y, Cui S, Chen J, Huang Y, Tang C, Shan B, Nie B. Effects of acupuncture at HT7 on glucose metabolism in a rat model of Alzheimer's disease: an 18F-FDG-PET study. Acupunct Med 2015; 34:215-22. [PMID: 26654890 PMCID: PMC4941154 DOI: 10.1136/acupmed-2015-010865] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2015] [Indexed: 12/21/2022]
Abstract
Objective To explore the effects of acupuncture at HT7 on different cerebral regions in a rat model of Alzheimer's disease (AD) with the application of 18F-2-fluoro-deoxy-D-glucose positron emission tomography (FDG-PET). Methods Sixty Wistar rats were included after undergoing a Y-maze electric sensitivity test. Ten rats were used as a healthy control group. The remaining 50 rats were injected stereotaxically with ibotenic acid into the right nucleus basalis magnocellularis and injected intraperitoneally with D-galactose. AD was successfully modelled in 36 rats, which were randomly divided into three groups (n=12 each): the AD group, which remained untreated; the AD+HT7 group, which received 20 sessions of acupuncture at HT7 over 1 month; and the AD+Sham group, which received acupuncture at a distant non-acupuncture point. Total reaction time (TRT) was measured by Y-maze and 18F-FDG-PET scans were conducted on day 1 and 30. PET images were processed with Statistical Parametric Mapping 8.0. Results Pre-treatment, TRT was greater in all AD groups versus controls (mean±SD 24.10±2.48 vs 41.34±5.00 s). Post-treatment, TRT was shortened in AD+HT7 versus AD+Sham and AD groups (p<0.0001, two-way analysis of variance). Glucose metabolic activity in the hippocampus, thalamus, hypothalamus, frontal lobe, and temporal lobe was decreased in AD rats compared with healthy controls and relatively elevated after HT7 acupuncture. Compared with sham acupuncture, HT7 needling had a greater positive influence on brain glucose metabolism. Conclusions Needling at HT7 can improve memory ability and cerebral glucose metabolic activity of the hippocampus, thalamus, hypothalamus, and frontal/temporal lobes in an AD rat model.
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Affiliation(s)
- Xinsheng Lai
- Department of Acupuncture and Massage, Guangzhou University of Traditional Chinese Medicine, Guangzhou, China
| | - Jie Ren
- School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China
| | - Yangjia Lu
- School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China
- Department of Traditional Chinese Medicine, Guangdong Medical College, Dongguan, China
| | - Shaoyang Cui
- Department of Acupuncture and Massage, Guangzhou University of Traditional Chinese Medicine, Guangzhou, China
- Department of Acupuncture and Moxibustion, Futian TCM Hospital, Shenzhen, China
| | - Junqi Chen
- School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China
- Department of Rehabilitation, The 3rd affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Yong Huang
- School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China
| | - Chunzhi Tang
- Department of Acupuncture and Massage, Guangzhou University of Traditional Chinese Medicine, Guangzhou, China
| | - Baoci Shan
- Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
| | - Bingbing Nie
- Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
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12
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Swanson MR, Wolff JJ, Elison JT, Gu H, Hazlett HC, Botteron K, Styner M, Paterson S, Gerig G, Constantino J, Dager S, Estes A, Vachet C, Piven J. Splenium development and early spoken language in human infants. Dev Sci 2015; 20. [PMID: 26490257 DOI: 10.1111/desc.12360] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 08/13/2015] [Indexed: 11/28/2022]
Abstract
The association between developmental trajectories of language-related white matter fiber pathways from 6 to 24 months of age and individual differences in language production at 24 months of age was investigated. The splenium of the corpus callosum, a fiber pathway projecting through the posterior hub of the default mode network to occipital visual areas, was examined as well as pathways implicated in language function in the mature brain, including the arcuate fasciculi, uncinate fasciculi, and inferior longitudinal fasciculi. The hypothesis that the development of neural circuitry supporting domain-general orienting skills would relate to later language performance was tested in a large sample of typically developing infants. The present study included 77 infants with diffusion weighted MRI scans at 6, 12 and 24 months and language assessment at 24 months. The rate of change in splenium development varied significantly as a function of language production, such that children with greater change in fractional anisotropy (FA) from 6 to 24 months produced more words at 24 months. Contrary to findings from older children and adults, significant associations between language production and FA in the arcuate, uncinate, or left inferior longitudinal fasciculi were not observed. The current study highlights the importance of tracing brain development trajectories from infancy to fully elucidate emerging brain-behavior associations while also emphasizing the role of the splenium as a key node in the structural network that supports the acquisition of spoken language.
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Affiliation(s)
- Meghan R Swanson
- The Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, USA
| | - Jason J Wolff
- The Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, USA.,Department of Educational Psychology, University of Minnesota, USA
| | - Jed T Elison
- Institute of Child Development, University of Minnesota, USA
| | - Hongbin Gu
- The Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, USA.,Department of Psychiatry, University of North Carolina at Chapel Hill, USA
| | - Heather C Hazlett
- The Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, USA.,Department of Psychiatry, University of North Carolina at Chapel Hill, USA
| | | | - Martin Styner
- The Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, USA.,Department of Psychiatry, University of North Carolina at Chapel Hill, USA.,Department of Computer Science, University of North Carolina at Chapel Hill, USA
| | - Sarah Paterson
- Department of Psychology, Temple University, USA.,Center for Autism Research, The Children's Hospital of Philadelphia, USA
| | - Guido Gerig
- Scientific Computing and Imaging Institute, University of Utah, USA
| | | | - Stephen Dager
- Department of Radiology, University of Washington, USA
| | - Annette Estes
- Department of Speech and Hearing Sciences, University of Washington, USA
| | - Clement Vachet
- Scientific Computing and Imaging Institute, University of Utah, USA
| | - Joseph Piven
- The Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, USA.,Department of Psychiatry, University of North Carolina at Chapel Hill, USA
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13
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Stylianou P, Hoffmann C, Blat I, Harnof S. Neuroimaging for patient selection for medial temporal lobe epilepsy surgery: Part 1 Structural neuroimaging. J Clin Neurosci 2015; 23:14-22. [PMID: 26362835 DOI: 10.1016/j.jocn.2015.04.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 03/27/2015] [Accepted: 04/05/2015] [Indexed: 11/19/2022]
Abstract
The objective of part one of this review is to present the structural neuroimaging techniques that are currently used to evaluate patients with temporal lobe epilepsy (TLE), and to discuss their potential to define patient eligibility for medial temporal lobe surgery. A PubMed query, using Medline and Embase, and subsequent review, was performed for all English language studies published after 1990, reporting neuroimaging methods for the evaluation of patients with TLE. The extracted data included demographic variables, population and study design, imaging methods, gold standard methods, imaging findings, surgical outcomes and conclusions. Overall, 56 papers were reviewed, including a total of 1517 patients. This review highlights the following structural neuroimaging techniques: MRI, diffusion-weighted imaging, tractography, electroencephalography and magnetoencephalography. The developments in neuroimaging during the last decades have led to remarkable improvements in surgical precision, postsurgical outcome, prognosis, and the rate of seizure control in patients with TLE. The use of multiple imaging methods provides improved outcomes, and further improvements will be possible with future studies of larger patient cohorts.
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Affiliation(s)
- Petros Stylianou
- Department of Neurosurgery, The Chaim Sheba Medical Center, Nissim Aloni 16, Tel Aviv-Yafo 62919, Israel.
| | - Chen Hoffmann
- Department of Radiology, The Chaim Sheba Medical Center, Tel Hashomer, Israel
| | - Ilan Blat
- Department of Neurology, The Chaim Sheba Medical Center, Tel Hashomer, Israel
| | - Sagi Harnof
- Department of Neurosurgery, The Chaim Sheba Medical Center, Nissim Aloni 16, Tel Aviv-Yafo 62919, Israel
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14
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Lee SH, Kim M, Park H. Planning for selective amygdalohippocampectomy involving less neuronal fiber damage based on brain connectivity using tractography. Neural Regen Res 2015; 10:1107-12. [PMID: 26330834 PMCID: PMC4541242 DOI: 10.4103/1673-5374.160104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2015] [Indexed: 01/23/2023] Open
Abstract
Temporal lobe resection is an important treatment option for epilepsy that involves removal of potentially essential brain regions. Selective amygdalohippocampectomy is a widely performed temporal lobe surgery. We suggest starting the incision for selective amygdalohippocampectomy at the inferior temporal gyrus based on diffusion magnetic resonance imaging (MRI) tractography. Diffusion MRI data from 20 normal participants were obtained from Parkinson's Progression Markers Initiative (PPMI) database (www.ppmi-info.org). A tractography algorithm was applied to extract neuronal fiber information for the temporal lobe, hippocampus, and amygdala. Fiber information was analyzed in terms of the number of fibers and betweenness centrality. Distances between starting incisions and surgical target regions were also considered to explore the length of the surgical path. Middle temporal and superior temporal gyrus regions have higher connectivity values than the inferior temporal gyrus and thus are not good candidates for starting the incision. The distances between inferior temporal gyrus and surgical target regions were shorter than those between middle temporal gyrus and target regions. Thus, the inferior temporal gyrus is a good candidate for starting the incision. Starting the incision from the inferior temporal gyrus would spare the important (in terms of betweenness centrality values) middle region and shorten the distance to the target regions of the hippocampus and amygdala.
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Affiliation(s)
- Seung-Hak Lee
- Department of Electronic Electrical and Computer Engineering, Sungkyunkwan University, Suwon, Republic of Korea
| | - Mansu Kim
- Graduate School of Human ICT Convergence, Sungkyunkwan University, Suwon, Republic of Korea
| | - Hyunjin Park
- School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon, Republic of Korea
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15
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Zhou F, Zhuang Y, Wang L, Zhang Y, Wu L, Zeng X, Gong H. Disconnection of the hippocampus and amygdala associated with lesion load in relapsing-remitting multiple sclerosis: a structural and functional connectivity study. Neuropsychiatr Dis Treat 2015; 11:1749-65. [PMID: 26229470 PMCID: PMC4514382 DOI: 10.2147/ndt.s84602] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND AND PURPOSE Little is known about the functional and structural connectivity (FC and SC) of the hippocampus and amygdala, which are two important structures involved in cognitive processes, or their involvement in relapsing-remitting multiple sclerosis (RRMS). In this study, we aimed to examine the connectivity of white-matter (WM) tracts and the synchrony of intrinsic neuronal activity in outer regions connected with the hippocampus or amygdala in RRMS patients. PATIENTS AND METHODS Twenty-three RRMS patients and 23 healthy subjects participated in this study. Diffusion tensor probabilistic tractography was used to examine the SC, the FC correlation coefficient (FC-CC) and combined FC strength (FCS), which was derived from the resting-state functional magnetic resonance imaging used to examine the FC, of the connection between the hippocampus or the amygdala and other regions, and the correlations of these connections with clinical markers. RESULTS Compared with healthy subjects, the RRMS patients showed significantly decreased SC and increased FCS of the bilateral hippocampus, and left amygdala. Their slightly increased FC-CC was positively correlated with WM tract damage in the right hippocampus (ρ=0.57, P=0.005); an increased FCS was also positively correlated with WM tract damage in the right amygdala. A relationship was observed between the WM lesion load and SC alterations, including the lg(N tracts) of the right hippocampus (ρ=-0.68, P<0.05), lg(N tracts) (ρ=-0.69, P<0.05), and fractional anisotropy (ρ=-0.68, P<0.05) and radial diffusivity of the left hippocampus (ρ=0.45, P<0.05). A relationship between WM lesion load and FCS of the left amygdale was also observed. CONCLUSION The concurrent increased functional connections and demyelination-related structural disconnectivity between the hippocampus or amygdala and other regions in RRMS suggest that the functional-structural relationships require further investigation.
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Affiliation(s)
- Fuqing Zhou
- Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, People's Republic of China ; Jiangxi Province Medical Imaging Research Institute, Jiangxi Province, People's Republic of China
| | - Ying Zhuang
- Department of Oncology, The Second Hospital of Nanchang, Nanchang, Jiangxi Province, People's Republic of China
| | - Lingling Wang
- Department of Geriatrics, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong Province, People's Republic of China
| | - Yue Zhang
- Department of Radiology, The Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi Province, People's Republic of China
| | - Lin Wu
- Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, People's Republic of China ; Jiangxi Province Medical Imaging Research Institute, Jiangxi Province, People's Republic of China
| | - Xianjun Zeng
- Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, People's Republic of China ; Jiangxi Province Medical Imaging Research Institute, Jiangxi Province, People's Republic of China
| | - Honghan Gong
- Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, People's Republic of China ; Jiangxi Province Medical Imaging Research Institute, Jiangxi Province, People's Republic of China
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16
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Differences in early and late mild cognitive impairment tractography using a diffusion tensor MRI. Neuroreport 2014; 25:1393-8. [DOI: 10.1097/wnr.0000000000000279] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Cortical and subcortical atrophy in Alzheimer disease: parallel atrophy of thalamus and hippocampus. Alzheimer Dis Assoc Disord 2014; 28:65-72. [PMID: 23751371 DOI: 10.1097/wad.0b013e318299d3d6] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Brain atrophy is a key imaging hallmark of Alzheimer disease (AD). In this study, we carried out an integrative evaluation of AD-related atrophy. Twelve patients with AD and 13 healthy controls were enrolled. We conducted a cross-sectional analysis of total brain tissue volumes with SIENAX. Localized gray matter atrophy was identified with optimized voxel-wise morphometry (FSL-VBM), and subcortical atrophy was evaluated by active shape model implemented in FMRIB's Integrated Registration Segmentation Toolkit. SIENAX analysis demonstrated total brain atrophy in AD patients; voxel-based morphometry analysis showed atrophy in the bilateral mediotemporal regions and in the posterior brain regions. In addition, regarding the diminished volumes of thalami and hippocampi in AD patients, subsequent vertex analysis of the segmented structures indicated shrinkage of the bilateral anterior thalami and the left medial hippocampus. Interestingly, the volume of the thalami and hippocampi were highly correlated with the volume of the thalami and amygdalae on both sides in AD patients, but not in healthy controls. This complex structural information proved useful in the detailed interpretation of AD-related neurodegenerative process, as the multilevel approach showed both global and local atrophy on cortical and subcortical levels. Most importantly, our results raise the possibility that subcortical structure atrophy is not independent in AD patients.
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18
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Behr C, D'Antuono M, Hamidi S, Herrington R, Lévesque M, Salami P, Shiri Z, Köhling R, Avoli M. Limbic networks and epileptiform synchronization: the view from the experimental side. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 114:63-87. [PMID: 25078499 DOI: 10.1016/b978-0-12-418693-4.00004-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this review, we summarize findings obtained in acute and chronic epilepsy models and in particular experiments that have revealed how neuronal networks in the limbic system-which is closely involved in the pathophysiogenesis of mesial temporal lobe epilepsy (MTLE)-produce hypersynchronous discharges. MTLE is often associated with a typical pattern of brain damage known as mesial temporal sclerosis, and it is one of the most refractory forms of partial epilepsy in adults. Specifically, we will address the cellular and pharmacological features of abnormal electrographic events that, as in MTLE patients, can occur in in vivo and in vitro animal models; these include interictal and ictal discharges along with high-frequency oscillations. In addition, we will consider how different limbic structures made hyperexcitable by acute pharmacological manipulations interact during epileptiform discharge generation. We will also review the electrographic characteristics of two types of seizure onsets that are most commonly seen in human and experimental MTLE as well as in in vitro models of epileptiform synchronization. Finally, we will address the role played by neurosteroids in reducing epileptiform synchronization and in modulating epileptogenesis.
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Affiliation(s)
- Charles Behr
- Department of Neurology, Neurosurgery and Physiology, Montréal Neurological Institute, Montréal, Québec, Canada
| | - Margherita D'Antuono
- Department of Neurology, Neurosurgery and Physiology, Montréal Neurological Institute, Montréal, Québec, Canada
| | - Shabnam Hamidi
- Department of Neurology, Neurosurgery and Physiology, Montréal Neurological Institute, Montréal, Québec, Canada
| | - Rochelle Herrington
- Department of Neurology, Neurosurgery and Physiology, Montréal Neurological Institute, Montréal, Québec, Canada
| | - Maxime Lévesque
- Department of Neurology, Neurosurgery and Physiology, Montréal Neurological Institute, Montréal, Québec, Canada
| | - Pariya Salami
- Department of Neurology, Neurosurgery and Physiology, Montréal Neurological Institute, Montréal, Québec, Canada
| | - Zahra Shiri
- Department of Neurology, Neurosurgery and Physiology, Montréal Neurological Institute, Montréal, Québec, Canada
| | - Rüdiger Köhling
- Institute of Physiology, University of Rostock, Rostock, Germany
| | - Massimo Avoli
- Department of Neurology, Neurosurgery and Physiology, Montréal Neurological Institute, Montréal, Québec, Canada; Department of Experimental Medicine, Facoltà di Medicina e Odontoiatria, Sapienza Università di Roma, Roma, Italy.
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19
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Wang Y, Toprani S, Tang Y, Vrabec T, Durand DM. Mechanism of highly synchronized bilateral hippocampal activity. Exp Neurol 2013; 251:101-11. [PMID: 24262205 DOI: 10.1016/j.expneurol.2013.11.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 10/09/2013] [Accepted: 11/10/2013] [Indexed: 11/27/2022]
Abstract
In vivo studies of epileptiform discharges in the hippocampi of rodents have shown that bilateral seizure activity can sometimes be synchronized with very small delays (<2 ms). This observed small time delay of epileptiform activity between the left and right CA3 regions is unexpected given the physiological propagation time across the hemispheres (>6 ms). The goal of this study is to determine the mechanisms of this tight synchronization with in-vitro electrophysiology techniques and computer simulations. The hypothesis of a common source was first eliminated by using an in-vitro preparation containing both hippocampi with a functional ventral hippocampal commissure (VHC) and no other tissue. Next, the hypothesis that a noisy baseline could mask the underlying synchronous activity between the two hemispheres was ruled out by low noise in-vivo recordings and computer simulation of the noisy environment. Then we built a novel bilateral CA3 model to test the hypothesis that the phenomenon of very small left-to-right propagation delay of seizure activity is a product of epileptic cell network dynamics. We found that the commissural tract connectivity could decrease the delay between seizure events recorded from two sides while the activity propagated longitudinally along the CA3 layer thereby yielding delays much smaller than the propagation time between the two sides. The modeling results indicate that both recurrent and feedforward inhibition were required for shortening the bilateral propagation delay and depended critically on the length of the commissural fiber tract as well as the number of cells involved in seizure generation. These combined modeling/experimental studies indicate that it is possible to explain near perfect synchronization between the two hemispheres by taking into account the structure of the hippocampal network.
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Affiliation(s)
- Y Wang
- Department of Biomedical Engineering, Zhejiang University, Room 217, Zhouyiqing Building, 38 Zheda Rd, Hangzhou, Zhejiang 310027, China.
| | - S Toprani
- Neural Engineering Center, Department of Biomedical Engineering Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Y Tang
- Neural Engineering Center, Department of Biomedical Engineering Case Western Reserve University, Cleveland, OH 44106, USA.
| | - T Vrabec
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - D M Durand
- Neural Engineering Center, Department of Biomedical Engineering Case Western Reserve University, Cleveland, OH 44106, USA.
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20
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Investigating the ventral-lexical, dorsal-sublexical model of basic reading processes using diffusion tensor imaging. Brain Struct Funct 2013; 220:445-55. [PMID: 24189777 DOI: 10.1007/s00429-013-0666-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 10/21/2013] [Indexed: 01/18/2023]
Abstract
Recent results from diffusion tensor imaging (DTI) studies provide evidence of a ventral-lexical stream and a dorsal-sublexical stream associated with reading processing. We investigated the relationship between behavioural reading speed for stimuli thought to rely on either the ventral-lexical, dorsal-sublexical, or both streams and white matter via fractional anisotropy (FA) and mean diffusivity (MD) using DTI tractography. Participants (N = 32) overtly named exception words (e.g., 'one', ventral-lexical), regular words (e.g., 'won', both streams), nonwords ('wum', dorsal-sublexical) and pseudohomophones ('wun', dorsal-sublexical) in a behavioural lab. Each participant then underwent a brain scan that included a 30-directional DTI sequence. Tractography was used to extract FA and MD values from four tracts of interest: inferior longitudinal fasciculus, uncinate fasciculus, arcuate fasciculus, and inferior fronto-occipital fasciculus. Median reaction times (RTs) for reading exception words and regular words both showed a significant correlation with the FA of the uncinate fasciculus thought to underlie the ventral processing stream, such that response time decreased as FA increased. In addition, RT for exception and regular words showed a relationship with MD of the uncinate fasciculus, such that response time increased as MD increased. Multiple regression analyses revealed that exception word RT accounted for unique variability in FA of the uncinate over and above regular words. There were no robust relationships found between pseudohomophones, or nonwords, and tracts thought to underlie the dorsal processing stream. These results support the notion that word recognition, in general, and exception word reading in particular, rely on ventral-lexical brain regions.
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21
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Haas BW, Barnea-Goraly N, Sheau KE, Yamagata B, Ullas S, Reiss AL. Altered microstructure within social-cognitive brain networks during childhood in Williams syndrome. ACTA ACUST UNITED AC 2013; 24:2796-806. [PMID: 23709644 DOI: 10.1093/cercor/bht135] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Williams syndrome (WS) is a neurodevelopmental condition caused by a hemizygous deletion of ∼26-28 genes on chromosome 7q11.23. WS is associated with a distinctive pattern of social cognition. Accordingly, neuroimaging studies show that WS is associated with structural alterations of key brain regions involved in social cognition during adulthood. However, very little is currently known regarding the neuroanatomical structure of social cognitive brain networks during childhood in WS. This study used diffusion tensor imaging to investigate the structural integrity of a specific set of white matter pathways (inferior fronto-occipital fasciculus [IFOF] and uncinate fasciculus [UF]) and associated brain regions [fusiform gyrus (FG), amygdala, hippocampus, medial orbitofrontal gyrus (MOG)] known to be involved in social cognition in children with WS and a typically developing (TD) control group. Children with WS exhibited higher fractional anisotropy (FA) and axial diffusivity values and lower radial diffusivity and apparent diffusion coefficient (ADC) values within the IFOF and UF, higher FA values within the FG, amygdala, and hippocampus and lower ADC values within the FG and MOG compared to controls. These findings provide evidence that the WS genetic deletion affects the development of key white matter pathways and brain regions important for social cognition.
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Affiliation(s)
- Brian W Haas
- Department of Psychology, University of Georgia, Center for Interdisciplinary Brain Sciences Research (CIBSR), Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Naama Barnea-Goraly
- Center for Interdisciplinary Brain Sciences Research (CIBSR), Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Kristen E Sheau
- Center for Interdisciplinary Brain Sciences Research (CIBSR), Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Bun Yamagata
- Center for Interdisciplinary Brain Sciences Research (CIBSR), Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Shruti Ullas
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Allan L Reiss
- Center for Interdisciplinary Brain Sciences Research (CIBSR), Department of Radiology, and Department of Pediatrics, Stanford University School of Medicine, 401 Quarry Rd. Palo Alto, CA 94305-5795, USA
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22
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Vonck K, Sprengers M, Carrette E, Dauwe I, Miatton M, Meurs A, Goossens L, DE Herdt V, Achten R, Thiery E, Raedt R, VAN Roost D, Boon P. A decade of experience with deep brain stimulation for patients with refractory medial temporal lobe epilepsy. Int J Neural Syst 2012; 23:1250034. [PMID: 23273130 DOI: 10.1142/s0129065712500347] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this study, we present long-term results from patients with medial temporal lobe (MTL) epilepsy treated with deep brain stimulation (DBS). Since 2001, 11 patients (8M) with refractory MTL epilepsy underwent MTL DBS. When unilateral DBS failed to decrease seizures by > 90%, a switch to bilateral MTL DBS was proposed. After a mean follow-up of 8.5 years (range: 67-120 months), 6/11 patients had a ≥ 90% seizure frequency reduction with 3/6 seizure-free for > 3 years; three patients had a 40%-70% reduction and two had a < 30% reduction. In 3/5 patients switching to bilateral DBS further improved outcome. Uni- or bilateral MTL DBS did not affect neuropsychological functioning. This open study with an extended long-term follow-up demonstrates maintained efficacy of DBS for MTL epilepsy. In more than half of the patients, a seizure frequency reduction of at least 90% was reached. Bilateral MTL DBS may herald superior efficacy in unilateral MTL epilepsy.
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Affiliation(s)
- Kristl Vonck
- Department of Neurology, Reference Center for Refractory Epilepsy, Gent, Belgium.
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23
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Arnold JF, Zwiers MP, Fitzgerald DA, van Eijndhoven P, Becker ES, Rinck M, Fernández G, Speckens AEM, Tendolkar I. Fronto-limbic microstructure and structural connectivity in remission from major depression. Psychiatry Res 2012; 204:40-8. [PMID: 23010567 DOI: 10.1016/j.pscychresns.2012.07.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 07/17/2012] [Accepted: 07/26/2012] [Indexed: 01/12/2023]
Abstract
Previous research has suggested that abnormalities within the amygdala and prefrontal cortex (PFC) may underlie major depressive disorder (MDD). The contribution of microstructural alterations within these regions in adult MDD is still equivocal. Therefore, seventeen middle-aged medication-free remitted MDD patients and 21 matched never-depressed control subjects underwent structural magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI). Despite comparable amygdala volumes, remitted MDD patients revealed decreased mean diffusivity (MD) and increased fractional anisotropy (FA) within the left amygdala, which may be interpreted as greater cell density and increased number of fibers, respectively. This last notion was supported by probabilistic tractography results, which revealed increased connectivity from the left amygdala to the hippocampus, the cerebellum and the brain stem. Further, altered microstructure as indicated by increased MD possibly reflecting decreased cell density within the medial PFC (mPFC) was found. Taken together, the current DTI study shows that abnormal microstructure and connectivity of the amygdala and mPFC might be key factors in the pathophysiology of MDD that may account for functional changes.
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Affiliation(s)
- Jennifer Fee Arnold
- Radboud University Nijmegen Medical Centre, Department of Psychiatry, Nijmegen, The Netherlands.
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Rashid S, Pho G, Czigler M, Werz MA, Durand DM. Low frequency stimulation of ventral hippocampal commissures reduces seizures in a rat model of chronic temporal lobe epilepsy. Epilepsia 2011; 53:147-56. [PMID: 22150779 DOI: 10.1111/j.1528-1167.2011.03348.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE To investigate the effects of low frequency stimulation (LFS) of a fiber tract for the suppression of spontaneous seizures in a rat model of human temporal lobe epilepsy. METHODS Stimulation electrodes were implanted into the ventral hippocampal commissure (VHC) in a rat post-status epilepticus (SE) model of human temporal lobe epilepsy (n = 7). Two recording electrodes were placed in the CA3 regions bilaterally and neural data were recorded for a minimum of 6 weeks. LFS (60 min train of 1 Hz biphasic square wave pulses, each 0.1 ms in duration and 200 μA in amplitude, followed by 15 min of rest) was applied to the VHC for 2 weeks, 24 h a day. KEY FINDINGS The baseline mean seizure frequency of the study animals was 3.7 seizures per day. The seizures were significantly reduced by the application of LFS in every animal (n = 7). By the end of the 2-week period of stimulation, there was a significant, 90% (<1 seizure/day) reduction of seizure frequencies (p < 0.05) and a 57% reduction during the period following LFS (p < 0.05) when compared to baseline. LFS also resulted in a significant reduction of hippocampal interictal spike frequency (71%, p < 0.05), during 2 weeks of LFS session. The hippocampal histologic analysis showed no significant difference between rats that received LFS and SE induction and those that had received only SE-induction. None of the animals showed any symptomatic hemorrhage, infection, or complication. SIGNIFICANCE Low frequency stimulation applied at a frequency of 1 Hz significantly reduced both the excitability of the neural tissue as well as the seizure frequency in a rat model of human temporal lobe epilepsy. The results support the hypothesis that LFS of fiber tracts can be an effective method for the suppression of spontaneous seizures in a temporal lobe model of epilepsy in rats and could lead to the development of a new therapeutic modality for human patients with temporal lobe epilepsy.
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Affiliation(s)
- Saifur Rashid
- Department of Biomedical Engineering, Neural Engineering Center, Case Western Reserve University, Cleveland, Ohio 44106, USA
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25
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Patel S, Mahon K, Wellington R, Zhang J, Chaplin W, Szeszko PR. A meta-analysis of diffusion tensor imaging studies of the corpus callosum in schizophrenia. Schizophr Res 2011; 129:149-55. [PMID: 21530178 DOI: 10.1016/j.schres.2011.03.014] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2010] [Revised: 03/01/2011] [Accepted: 03/10/2011] [Indexed: 12/11/2022]
Abstract
BACKGROUND The corpus callosum has been hypothesized to play an important role in neurobiological models of schizophrenia. Diffusion tensor imaging studies have provided evidence for a disruption in corpus callosum morphology in schizophrenia, but the regional distribution of abnormalities is not well known. METHODS We conducted 2 meta-analyses investigating the genu and splenium of the corpus callosum in schizophrenia, respectively, based on published diffusion tensor imaging studies that employed a region-of-interest approach. Seven studies investigating the genu and splenium involving a total of 202 patients with schizophrenia and 213 healthy volunteers were included. RESULTS The meta-analysis of the genu yielded an effect size of 0.223 and was not statistically significant. The second meta-analysis investigating the splenium yielded a modest effect size of 0.527 (p=0.001), indicating that patients had lower fractional anisotropy in this region compared to healthy volunteers. Studies that included fewer men had a larger effect size for the splenium. DISCUSSION These findings implicate an abnormality involving the splenium of the corpus callosum in the neurobiology of schizophrenia as inferred by diffusion tensor imaging. A defect in the splenium could contribute to abnormalities in posterior interhemispheric connectivity in patients, including regions of the heteromodal association cortex.
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Affiliation(s)
- Shivani Patel
- Center for Psychiatric Neuroscience, Feinstein Institute for Medical Research, Manhasset, NY, USA
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26
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Selective amygdalohippocampectomy. EPILEPSY RESEARCH AND TREATMENT 2011; 2012:382095. [PMID: 22957229 PMCID: PMC3420672 DOI: 10.1155/2012/382095] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 02/22/2011] [Accepted: 03/25/2011] [Indexed: 11/17/2022]
Abstract
Epilepsy surgery can be an effective epilepsy treatment for patients whose seizures do not respond to best medical therapy. For patients with temporal lobe epilepsy, selective amygdalohippocampectomy (SAH) has emerged as a viable alternative to standard anterior temporal lobectomy. This paper reviews the indications for SAH, the technical advances that have led to greater adoption of the procedure, the expectations for seizure control, and the risks of morbidity.
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Zamarian L, Trinka E, Bonatti E, Kuchukhidze G, Bodner T, Benke T, Koppelstaetter F, Delazer M. Executive functions in chronic mesial temporal lobe epilepsy. EPILEPSY RESEARCH AND TREATMENT 2011; 2011:596174. [PMID: 22937233 PMCID: PMC3428608 DOI: 10.1155/2011/596174] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 12/06/2010] [Accepted: 01/11/2011] [Indexed: 12/02/2022]
Abstract
There is no consensus as to whether mesial temporal lobe epilepsy (MTLE) leads to executive function deficits. In this study, we adopted an extensive neuropsychological test battery and assessed different executive functions in chronic, unilateral MTLE. Performance of MTLE patients was compared with that of healthy peers and with normative data. Several MTLE patients had scores below cut-off or below the 10th percentile of normative data. Scores of the whole patient group were overall in the average range of normative data. Relative to controls, MTLE patients performed poorly in tests of working memory, cognitive flexibility, categorical verbal fluency, set-shifting, categorization, and planning. These findings raise an important methodological issue as they suggest that executive function deficits in chronic MTLE may be individually variable and that their assessment should include different tests. Deficits in chronic MTLE are not limited to temporal lobe functions, such as memory, but may extend to extra temporal cognitive domains, such as executive functions.
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Affiliation(s)
- Laura Zamarian
- Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Eugen Trinka
- Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
- Department of Neurology, Christian Doppler Clinic, Paracelsus Medical University, Ignaz Herrer Strasse 79, 5020 Salzburg, Austria
| | - Elisabeth Bonatti
- Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Giorgi Kuchukhidze
- Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Thomas Bodner
- Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Thomas Benke
- Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Florian Koppelstaetter
- Clinical Department of Radiology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Margarete Delazer
- Clinical Department of Neurology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
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