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Trambaiolli L, Maffei C, Dann E, Biazoli C, Bezgin G, Yendiki A, Haber S. Translation of monosynaptic circuits underlying amygdala fMRI neurofeedback training. Neuropsychopharmacology 2024:10.1038/s41386-024-01944-w. [PMID: 39103495 DOI: 10.1038/s41386-024-01944-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Revised: 07/16/2024] [Accepted: 07/23/2024] [Indexed: 08/07/2024]
Abstract
fMRI neurofeedback using autobiographical memory recall to upregulate the amygdala is associated with resting-state functional connectivity (rsFC) changes between the amygdala and the salience and default mode networks (SN and DMN, respectively). We hypothesize the existence of anatomical circuits underlying these rsFC changes. Using a cross-species brain parcellation, we identified in non-human primates locations homologous to the regions of interest (ROIs) from studies showing pre-to-post-neurofeedback changes in rsFC with the left amygdala. We injected bidirectional tracers in the basolateral, lateral, and central amygdala nuclei of adult macaques and used bright- and dark-field microscopy to identify cells and axon terminals in each ROI (SN: anterior cingulate, ventrolateral, and insular cortices; DMN: temporal pole, middle frontal gyrus, angular gyrus, precuneus, posterior cingulate cortex, parahippocampal gyrus, hippocampus, and thalamus). We also performed additional injections in specific ROIs to validate the results following amygdala injections and delineate potential disynaptic pathways. Finally, we used high-resolution diffusion MRI data from four post-mortem macaque brains and one in vivo human brain to translate our findings to the neuroimaging domain. Different amygdala nuclei had significant monosynaptic connections with all the SN and DMN ipsilateral ROIs. Amygdala connections with the DMN contralateral ROIs are disynaptic through the hippocampus and parahippocampal gyrus. Diffusion MRI in both species benefitted from using the ground-truth tracer data to validate its findings, as we identified false-negative ipsilateral and false-positive contralateral connectivity results. This study provides the foundation for future causal investigations of amygdala neurofeedback modulation of the SN and DMN through these anatomic connections.
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Affiliation(s)
- Lucas Trambaiolli
- McLean Hospital, Harvard Medical School, Boston, MA, USA.
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA.
| | - Chiara Maffei
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Evan Dann
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Claudinei Biazoli
- Center for Mathematics Computation and Cognition, Federal University of ABC, Santo André, Brazil
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Gleb Bezgin
- Neuroinformatics for Personalized Medicine lab, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Anastasia Yendiki
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Suzanne Haber
- McLean Hospital, Harvard Medical School, Boston, MA, USA.
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA.
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2
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Szczupak D, Schaeffer DJ, Tian X, Choi SH, Fang-Cheng, Iack PM, Campos VP, Mayo JP, Patsch J, Mitter C, Haboosheh A, Kwon HS, Vieira MAC, Reich DS, Jacobson S, Kasprian G, Tovar-Moll F, Lent R, Silva AC. Direct interhemispheric cortical communication via thalamic commissures: a new white matter pathway in the primate brain. Cereb Cortex 2024; 34:bhad394. [PMID: 37950874 PMCID: PMC10793074 DOI: 10.1093/cercor/bhad394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 10/02/2023] [Accepted: 10/03/2023] [Indexed: 11/13/2023] Open
Abstract
Cortical neurons of eutherian mammals project to the contralateral hemisphere, crossing the midline primarily via the corpus callosum and the anterior, posterior, and hippocampal commissures. We recently reported and named the thalamic commissures (TCs) as an additional interhemispheric axonal fiber pathway connecting the cortex to the contralateral thalamus in the rodent brain. Here, we demonstrate that TCs also exist in primates and characterize the connectivity of these pathways with high-resolution diffusion-weighted MRI, viral axonal tracing, and fMRI. We present evidence of TCs in both New World (Callithrix jacchus and Cebus apella) and Old World primates (Macaca mulatta). Further, like rodents, we show that the TCs in primates develop during the embryonic period, forming anatomical and functionally active connections of the cortex with the contralateral thalamus. We also searched for TCs in the human brain, showing their presence in humans with brain malformations, although we could not identify TCs in healthy subjects. These results pose the TCs as a vital fiber pathway in the primate brain, allowing for more robust interhemispheric connectivity and synchrony and serving as an alternative commissural route in developmental brain malformations.
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Affiliation(s)
- Diego Szczupak
- University of Pittsburgh Brain Institute, Department of Neurobiology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA
| | - David J Schaeffer
- University of Pittsburgh Brain Institute, Department of Neurobiology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA
| | - Xiaoguang Tian
- University of Pittsburgh Brain Institute, Department of Neurobiology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA
| | - Sang-Ho Choi
- University of Pittsburgh Brain Institute, Department of Neurobiology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA
| | - Fang-Cheng
- Department of Neurological Surgery, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA 15261, USA
| | - Pamela Meneses Iack
- Biomedical Sciences Institute, Federal University of Rio de Janeiro, 373 Carlos Chagas Filho Avenue, Rio de Janeiro, Rio de Janeiro 21941-853, Brazil
| | - Vinicius P Campos
- Department of Electrical and Computer Engineering, 400 Trabalhador São-Carlense Avenue, University of São Paulo, São Carlos, SP 13565-905, Brazil
| | - J Patrick Mayo
- Department of Ophthalmology, University of Pittsburgh, 1622 Locust Street, Pittsburgh, PA 15261, USA
| | - Janina Patsch
- Department of Biomedical Imaging and Image-Guided Therapy of the Medical University of Vienna, 18-20 Währinger Gürtel, 1090, Vienna, Austria
| | - Christian Mitter
- Department of Biomedical Imaging and Image-Guided Therapy of the Medical University of Vienna, 18-20 Währinger Gürtel, 1090, Vienna, Austria
| | - Amit Haboosheh
- Department of Radiology Hadassah Ein Karem Hospital, Kalman Ya'akov Man St, Jerusalem 9112001, Israel
| | - Ha Seung Kwon
- University of Pittsburgh Brain Institute, Department of Neurobiology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA
| | - Marcelo A C Vieira
- Department of Electrical and Computer Engineering, 400 Trabalhador São-Carlense Avenue, University of São Paulo, São Carlos, SP 13565-905, Brazil
| | - Daniel S Reich
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, Bethesda, MD 20814, USA
| | - Steve Jacobson
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, Bethesda, MD 20814, USA
| | - Gregor Kasprian
- Department of Biomedical Imaging and Image-Guided Therapy of the Medical University of Vienna, 18-20 Währinger Gürtel, 1090, Vienna, Austria
| | - Fernanda Tovar-Moll
- D’Or Institute of Research and Education, 30 Rua Diniz Cordeiro Street, Rio de Janeiro, Rio de Janeiro 22281-100, Brazil
| | - Roberto Lent
- Biomedical Sciences Institute, Federal University of Rio de Janeiro, 373 Carlos Chagas Filho Avenue, Rio de Janeiro, Rio de Janeiro 21941-853, Brazil
- D’Or Institute of Research and Education, 30 Rua Diniz Cordeiro Street, Rio de Janeiro, Rio de Janeiro 22281-100, Brazil
| | - Afonso C Silva
- University of Pittsburgh Brain Institute, Department of Neurobiology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA
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3
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Szczupak D, Schaeffer DJ, Tian X, Choi SH, Fang-Cheng, Iack PM, Campos VP, Mayo JP, Patsch J, Mitter C, Haboosheh A, Vieira MA, Kasprian G, Tovar-Moll F, Lent R, Silva AC. Direct interhemispheric cortical communication via thalamic commissures: a new white-matter pathway in the primate brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.15.545128. [PMID: 37398056 PMCID: PMC10312754 DOI: 10.1101/2023.06.15.545128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Cortical neurons of eutherian mammals project to the contralateral hemisphere, crossing the midline primarily via the corpus callosum and the anterior, posterior, and hippocampal commissures. We recently reported an additional commissural pathway in rodents, termed the thalamic commissures (TCs), as another interhemispheric axonal fiber pathway that connects cortex to the contralateral thalamus. Here, we demonstrate that TCs also exist in primates and characterize the connectivity of these pathways with high-resolution diffusion-weighted magnetic resonance imaging, viral axonal tracing, and functional MRI. We present evidence of TCs in both New World (Callithrix jacchus and Cebus apella) and Old World primates (Macaca mulatta). Further, like rodents, we show that the TCs in primates develop during the embryonic period, forming anatomical and functionally active connections of the cortex with the contralateral thalamus. We also searched for TCs in the human brain, showing their presence in humans with brain malformations, although we could not identify TCs in healthy subjects. These results pose the TCs as an important fiber pathway in the primate brain, allowing for more robust interhemispheric connectivity and synchrony and serving as an alternative commissural route in developmental brain malformations.
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Affiliation(s)
- Diego Szczupak
- University of Pittsburgh Brain Institute, Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - David J. Schaeffer
- University of Pittsburgh Brain Institute, Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Xiaoguang Tian
- University of Pittsburgh Brain Institute, Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Sang-Ho Choi
- University of Pittsburgh Brain Institute, Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Fang-Cheng
- Department of Neurological Surgery University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Pamela Meneses Iack
- Department of Neurological Surgery University of Pittsburgh, Pittsburgh, PA 15261, USA
| | | | - J. Patrick Mayo
- Department of Electrical and Computer Engineering, University of São Paulo, São Carlos, SP 13565-905, Brazil
| | - Janina Patsch
- Department of Biomedical Imaging and Image-guided therapy of the Medical University of Vienna, 1090, Austria
| | - Christian Mitter
- Department of Biomedical Imaging and Image-guided therapy of the Medical University of Vienna, 1090, Austria
| | - Amit Haboosheh
- Department Of Radiology Hadassah Ein Karem Hospital, Jerusalem 9112001, Israel
| | - Marcelo A.C. Vieira
- Department of Electrical and Computer Engineering, University of São Paulo, São Carlos, SP 13565-905, Brazil
| | - Gregor Kasprian
- Department of Biomedical Imaging and Image-guided therapy of the Medical University of Vienna, 1090, Austria
| | | | - Roberto Lent
- Federal University of Rio de Janeiro, Rio de Janeiro 21941-853, Brazil
- D’Or Institute of Research and Education, Rio de Janeiro 22281-100, Brazil
| | - Afonso C. Silva
- University of Pittsburgh Brain Institute, Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Diffusion magnetic resonance tractography-based evaluation of commissural fiber abnormalities in a heparan sulfate endosulfatase-deficient mouse brain. Magn Reson Imaging 2022; 88:123-131. [DOI: 10.1016/j.mri.2022.01.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 01/28/2022] [Accepted: 01/29/2022] [Indexed: 11/21/2022]
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5
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Fernandez AM, Gutekunst CA, Grogan DP, Pedersen NP, Gross RE. Loss of efferent projections of the hippocampal formation in the mouse intrahippocampal kainic acid model. Epilepsy Res 2022; 180:106863. [PMID: 35114430 DOI: 10.1016/j.eplepsyres.2022.106863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 12/15/2021] [Accepted: 01/17/2022] [Indexed: 11/16/2022]
Abstract
Unilateral intrahippocampal injection of kainic acid is used as a model of medial temporal lobe epilepsy and provides a platform to study the mechanisms of epilepsy. Here, we used an AAV-9 EYFP-tagged viral vector as an anterograde tracer, injected into the dorsal and ventral hippocampus after kainic acid injection, to map out the efferent hippocampal projections after the development of spontaneous seizures in this model. The purpose of the study was to identify the extent of changes in hippocampal efferent system in several brain regions that receive significant inputs from the hippocampus. Loss of efferent hippocampal fibers was greatest in the retrosplenial cortex where neuronal loss was also observed. Loss of fibers was also observed in the fornix without any specific effect in the lateral mammillary nuclei. Although expected, these observations provide further evidence of the broader network effects as a result of hippocampal cell loss.
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Affiliation(s)
- Alejandra M Fernandez
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Claire-Anne Gutekunst
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, 30322, USA.
| | - Dayton P Grogan
- Department of Neurosurgery, Augusta University Hospital, Augusta, GA, 30912, USA
| | - Nigel P Pedersen
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA; Department of Neurology, Emory University, Atlanta, GA, 30322, USA
| | - Robert E Gross
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, 30322, USA; Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA; Department of Neurology, Emory University, Atlanta, GA, 30322, USA.
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Szczupak D, Iack PM, Liu C, Tovar-Moll F, Lent R, Silva AC. Direct Interhemispheric Cortical Communication via Thalamic Commissures: A New White-Matter Pathway in the Rodent Brain. Cereb Cortex 2021; 31:4642-4651. [PMID: 33999140 PMCID: PMC8408456 DOI: 10.1093/cercor/bhab112] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/16/2021] [Accepted: 04/07/2021] [Indexed: 11/14/2022] Open
Abstract
The corpus callosum (CC), the anterior (AC), and the posterior (PC) commissures are the principal axonal fiber bundle pathways that allow bidirectional communication between the brain hemispheres. Here, we used the Allen mouse brain connectivity atlas and high-resolution diffusion-weighted MRI (DWI) to investigate interhemispheric fiber bundles in C57bl6/J mice, the most commonly used wild-type mouse model in biomedical research. We identified 1) commissural projections from the primary motor area through the AC to the contralateral hemisphere; and 2) intrathalamic interhemispheric fiber bundles from multiple regions in the frontal cortex to the contralateral thalamus. This is the first description of direct interhemispheric corticothalamic connectivity from the orbital cortex. We named these newly identified crossing points thalamic commissures. We also analyzed interhemispheric connectivity in the Balb/c mouse model of dysgenesis of the corpus callosum (CCD). Relative to C57bl6/J, Balb/c presented an atypical and smaller AC and weaker interhemispheric corticothalamic communication. These results redefine our understanding of interhemispheric brain communication. Specifically, they establish the thalamus as a regular hub for interhemispheric connectivity and encourage us to reinterpret brain plasticity in CCD as an altered balance between axonal reinforcement and pruning.
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Affiliation(s)
- Diego Szczupak
- Department of Neurobiology, University of Pittsburgh Brain Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Cerebral Microcirculation Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Pamela Meneses Iack
- Biomedical Sciences Institute, Federal University of Rio de Janeiro, Rio de Janeiro 21941-590, Brazil
| | - Cirong Liu
- Department of Neurobiology, University of Pittsburgh Brain Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Cerebral Microcirculation Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- Institute of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - IRC5 Consortium
- Researchers of the International Research Consortium for the Corpus Callosum and Cerebral Connectivity (IRC5), Pasadena, CA 91125, USA
| | | | - Roberto Lent
- Biomedical Sciences Institute, Federal University of Rio de Janeiro, Rio de Janeiro 21941-590, Brazil
- D’Or Institute of Research and Education, Rio de Janeiro 22281-100, Brazil
| | - Afonso C Silva
- Department of Neurobiology, University of Pittsburgh Brain Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Cerebral Microcirculation Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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7
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Huang JY, Krebs BB, Miskus ML, Russell ML, Duffy EP, Graf JM, Lu HC. Enhanced FGFR3 activity in postmitotic principal neurons during brain development results in cortical dysplasia and axonal tract abnormality. Sci Rep 2020; 10:18508. [PMID: 33116259 PMCID: PMC7595096 DOI: 10.1038/s41598-020-75537-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 09/30/2020] [Indexed: 02/07/2023] Open
Abstract
Abnormal levels of fibroblast growth factors (FGFs) and FGF receptors (FGFRs) have been detected in various neurological disorders. The potent impact of FGF-FGFR in multiple embryonic developmental processes makes it challenging to elucidate their roles in postmitotic neurons. Taking an alternative approach to examine the impact of aberrant FGFR function on glutamatergic neurons, we generated a FGFR gain-of-function (GOF) transgenic mouse, which expresses constitutively activated FGFR3 (FGFR3K650E) in postmitotic glutamatergic neurons. We found that GOF disrupts mitosis of radial-glia neural progenitors (RGCs), inside-out radial migration of post-mitotic glutamatergic neurons, and axonal tract projections. In particular, late-born CUX1-positive neurons are widely dispersed throughout the GOF cortex. Such a cortical migration deficit is likely caused, at least in part, by a significant reduction of the radial processes projecting from RGCs. RNA-sequencing analysis of the GOF embryonic cortex reveals significant alterations in several pathways involved in cell cycle regulation and axonal pathfinding. Collectively, our data suggest that FGFR3 GOF in postmitotic neurons not only alters axonal growth of postmitotic neurons but also impairs RGC neurogenesis and radial glia processes.
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Affiliation(s)
- Jui-Yen Huang
- Department of Psychological and Brain Sciences, the Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, 1101 E. 10th Street, Bloomington, IN, 47405, USA.
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA.
| | - Bruna Baumgarten Krebs
- Department of Psychological and Brain Sciences, the Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, 1101 E. 10th Street, Bloomington, IN, 47405, USA
| | - Marisha Lynn Miskus
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - May Lin Russell
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Eamonn Patrick Duffy
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Jason Michael Graf
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Hui-Chen Lu
- Department of Psychological and Brain Sciences, the Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, 1101 E. 10th Street, Bloomington, IN, 47405, USA.
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA.
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Deconstructing the Direct Reciprocal Hippocampal-Anterior Thalamic Pathways for Spatial Learning. J Neurosci 2020; 40:6978-6990. [PMID: 32753513 PMCID: PMC7470921 DOI: 10.1523/jneurosci.0874-20.2020] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 07/14/2020] [Accepted: 07/19/2020] [Indexed: 01/13/2023] Open
Abstract
The hippocampus is essential for normal memory but does not act in isolation. The anterior thalamic nuclei may represent one vital partner. Using DREADDs, the behavioral consequences of transiently disrupting anterior thalamic function were examined, followed by inactivation of the dorsal subiculum. Next, the anterograde transport of an adeno-associated virus expressing DREADDs was paired with localized intracerebral infusions of a ligand to target specific input pathways. In this way, the direct projections from the anterior thalamic nuclei to the dorsal hippocampal formation were inhibited, followed by separate inhibition of the dorsal subiculum projections to the anterior thalamic nuclei. To assay spatial working memory, all animals performed a reinforced T-maze alternation task, then a more challenging version that nullifies intramaze cues. Across all four experiments, deficits emerged on the spatial alternation task that precluded the use of intramaze cues. Inhibiting dorsal subiculum projections to the anterior thalamic nuclei produced the severest spatial working memory deficit. This deficit revealed the key contribution of dorsal subiculum projections to the anteromedial and anteroventral thalamic nuclei for the processing of allocentric information, projections not associated with head-direction information. The overall pattern of results provides consistent causal evidence of the two-way functional significance of direct hippocampal-anterior thalamic interactions for spatial processing. At the same time, these findings are consistent with hypotheses that these same, reciprocal interactions underlie the common core symptoms of temporal lobe and diencephalic anterograde amnesia. SIGNIFICANCE STATEMENT It has long been conjectured that the anterior thalamic nuclei might be key partners with the hippocampal formation and that, respectively, they are principally responsible for diencephalic and temporal lobe amnesia. However, direct causal evidence for this functional relationship is lacking. Here, we examined the behavioral consequences of transiently silencing the direct reciprocal interconnections between these two brain regions on tests of spatial learning. Disrupting information flow from the hippocampal formation to the anterior thalamic nuclei and vice versa impaired performance on tests of spatial learning. By revealing the conjoint importance of hippocampal-anterior thalamic pathways, these findings help explain why pathology in either the medial diencephalon or the medial temporal lobes can result in profound anterograde amnesic syndromes.
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Masuda-Suzukake M, Suzuki G, Hosokawa M, Nonaka T, Goedert M, Hasegawa M. Dextran sulphate-induced tau assemblies cause endogenous tau aggregation and propagation in wild-type mice. Brain Commun 2020; 2:fcaa091. [PMID: 33005889 PMCID: PMC7519727 DOI: 10.1093/braincomms/fcaa091] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 06/11/2020] [Accepted: 06/14/2020] [Indexed: 12/19/2022] Open
Abstract
Accumulation of assembled tau protein in the central nervous system is characteristic of Alzheimer’s disease and several other neurodegenerative diseases, called tauopathies. Recent studies have revealed that propagation of assembled tau is key to understanding the pathological mechanisms of these diseases. Mouse models of tau propagation are established by injecting human-derived tau seeds intracerebrally; nevertheless, these have a limitation in terms of regulation of availability. To date, no study has shown that synthetic assembled tau induce tau propagation in non-transgenic mice. Here we confirm that dextran sulphate, a sulphated glycosaminoglycan, induces the assembly of recombinant tau protein into filaments in vitro. As compared to tau filaments induced by heparin, those induced by dextran sulphate showed higher thioflavin T fluorescence and lower resistance to guanidine hydrochloride, which suggests that the two types of filaments have distinct conformational features. Unlike other synthetic filament seeds, intracerebral injection of dextran sulphate-induced assemblies of recombinant tau caused aggregation of endogenous murine tau in wild-type mice. AT8-positive tau was present at the injection site 1 month after injection, from where it spread to anatomically connected regions. Induced tau assemblies were also stained by anti-tau antibodies AT100, AT180, 12E8, PHF1, anti-pS396 and anti-pS422. They were thioflavin- and Gallyas-Braak silver-positive, indicative of amyloid. In biochemical analyses, accumulated sarkosyl-insoluble and hyperphosphorylated tau was observed in the injected mice. In conclusion, we revealed that intracerebral injection of synthetic full-length wild-type tau seeds prepared in the presence of dextran sulphate caused tau propagation in non-transgenic mice. These findings establish that propagation of tau assemblies does not require tau to be either mutant and/or overexpressed.
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Affiliation(s)
- Masami Masuda-Suzukake
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506, Japan
| | - Genjiro Suzuki
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506, Japan
| | - Masato Hosokawa
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506, Japan
| | - Takashi Nonaka
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506, Japan
| | - Michel Goedert
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Masato Hasegawa
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506, Japan
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10
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Williams AN, Ridgeway S, Postans M, Graham KS, Lawrence AD, Hodgetts CJ. The role of the pre-commissural fornix in episodic autobiographical memory and simulation. Neuropsychologia 2020; 142:107457. [PMID: 32259556 PMCID: PMC7322517 DOI: 10.1016/j.neuropsychologia.2020.107457] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/25/2020] [Accepted: 03/30/2020] [Indexed: 12/13/2022]
Abstract
Neuropsychological and functional magnetic resonance imaging evidence suggests that the ability to vividly remember our personal past, and imagine future scenarios, involves two closely connected regions: the hippocampus and ventromedial prefrontal cortex (vmPFC). Despite evidence of a direct anatomical connection from hippocampus to vmPFC, it is unknown whether hippocampal-vmPFC structural connectivity supports both past- and future-oriented episodic thinking. To address this, we applied a novel deterministic tractography protocol to diffusion-weighted magnetic resonance imaging (dMRI) data from a group of healthy young adult humans who undertook an adapted past-future autobiographical interview (portions of this data were published in Hodgetts et al., 2017a). This tractography protocol enabled distinct subdivisions of the fornix, detected previously in axonal tracer studies, to be reconstructed in vivo, namely the pre-commissural (connecting the hippocampus to vmPFC) and post-commissural (linking the hippocampus and medial diencephalon) fornix. As predicted, we found that inter-individual differences in pre-commissural - but not post-commissural - fornix microstructure (fractional anisotropy) were significantly correlated with the episodic richness of both past and future autobiographical narratives. Notably, these results held when controlling for non-episodic narrative content, verbal fluency, and grey matter volumes of the hippocampus and vmPFC. This study provides novel evidence that reconstructing events from one's personal past, and constructing possible future events, involves a distinct, structurally-instantiated hippocampal-vmPFC pathway.
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Affiliation(s)
- Angharad N Williams
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, United Kingdom; Max Planck Research Group Adaptive Memory, Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstraße 1a, 04103, Leipzig, Germany.
| | - Samuel Ridgeway
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, United Kingdom
| | - Mark Postans
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, United Kingdom
| | - Kim S Graham
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, United Kingdom
| | - Andrew D Lawrence
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, United Kingdom.
| | - Carl J Hodgetts
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, United Kingdom; Department of Psychology, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, United Kingdom
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Coad BM, Craig E, Louch R, Aggleton JP, Vann SD, Metzler-Baddeley C. Precommissural and postcommissural fornix microstructure in healthy aging and cognition. Brain Neurosci Adv 2020; 4:2398212819899316. [PMID: 32219177 PMCID: PMC7085915 DOI: 10.1177/2398212819899316] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/11/2019] [Indexed: 11/23/2022] Open
Abstract
The fornix is a key tract of the hippocampal formation, whose status is presumed to contribute to age-related cognitive decline. The precommissural and postcommissural fornix subdivisions form respective basal forebrain/frontal and diencephalic networks that may differentially affect aging and cognition. We employed multi-parametric magnetic resonance imaging (MRI) including neurite orientation density and dispersion imaging, quantitative magnetization transfer (qMT), and T1-relaxometry MRI to investigate the microstructural properties of these fornix subdivisions and their relationship with aging and cognition in 149 asymptomatic participants (38-71 years). Aging was associated with increased free water signal and reductions in myelin-sensitive R1 and qMT indices but no apparent axon density differences in both precommissural and postcommissural fibers. Precommissural relative to postcommissural fibers showed a distinct microstructural pattern characterised by larger free water signal and axon orientation dispersion, with lower apparent myelin and axon density. Furthermore, differences in postcommissural microstructure were related to performance differences in object-location paired-associate learning. These results provide novel in vivo neuroimaging evidence for distinct microstructural properties of precommissural and postcommissural fibers that are consistent with their anatomy as found in axonal tracer studies, as well as for a contribution of postcommissural fibers to the learning of spatial configurations.
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Affiliation(s)
- Bethany M. Coad
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff, UK
- School of Psychology, Cardiff University, Cardiff, UK
| | - Emma Craig
- School of Psychology, Cardiff University, Cardiff, UK
| | - Rebecca Louch
- School of Psychology, Cardiff University, Cardiff, UK
| | | | | | - Claudia Metzler-Baddeley
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff, UK
- School of Psychology, Cardiff University, Cardiff, UK
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