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Rojo C, Leguey I, Kastanauskaite A, Bielza C, Larrañaga P, DeFelipe J, Benavides-Piccione R. Laminar Differences in Dendritic Structure of Pyramidal Neurons in the Juvenile Rat Somatosensory Cortex. Cereb Cortex 2016; 26:2811-2822. [PMID: 26762857 PMCID: PMC4869814 DOI: 10.1093/cercor/bhv316] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Pyramidal cell structure varies between different cortical areas and species, indicating that the cortical circuits that these cells participate in are likely to be characterized by different functional capabilities. Structural differences between cortical layers have been traditionally reported using either the Golgi method or intracellular labeling, but the structure of pyramidal cells has not previously been systematically analyzed across all cortical layers at a particular age. In the present study, we investigated the dendritic architecture of complete basal arbors of pyramidal neurons in layers II, III, IV, Va, Vb, and VI of the hindlimb somatosensory cortical region of postnatal day 14 rats. We found that the characteristics of basal dendritic morphologies are statistically different in each cortical layer. The variations in size and branching pattern that exist between pyramidal cells of different cortical layers probably reflect the particular functional properties that are characteristic of the cortical circuit in which they participate. This new set of complete basal dendritic arbors of 3D-reconstructed pyramidal cell morphologies across each cortical layer will provide new insights into interlaminar information processing in the cerebral cortex.
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Affiliation(s)
- Concepción Rojo
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica.,Departamento de Anatomía y Anatomía Patológica Comparada, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain
| | - Ignacio Leguey
- Departamento de Inteligencia Artificial, Escuela Técnica Superior de Ingenieros Informáticos, Universidad Politécnica de Madrid, Madrid, Spain
| | - Asta Kastanauskaite
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Concha Bielza
- Departamento de Inteligencia Artificial, Escuela Técnica Superior de Ingenieros Informáticos, Universidad Politécnica de Madrid, Madrid, Spain
| | - Pedro Larrañaga
- Departamento de Inteligencia Artificial, Escuela Técnica Superior de Ingenieros Informáticos, Universidad Politécnica de Madrid, Madrid, Spain
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica.,Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Ruth Benavides-Piccione
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica.,Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
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Chaudhuri R, Knoblauch K, Gariel MA, Kennedy H, Wang XJ. A Large-Scale Circuit Mechanism for Hierarchical Dynamical Processing in the Primate Cortex. Neuron 2015; 88:419-31. [PMID: 26439530 DOI: 10.1016/j.neuron.2015.09.008] [Citation(s) in RCA: 327] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 05/24/2015] [Accepted: 08/28/2015] [Indexed: 12/15/2022]
Abstract
We developed a large-scale dynamical model of the macaque neocortex, which is based on recently acquired directed- and weighted-connectivity data from tract-tracing experiments, and which incorporates heterogeneity across areas. A hierarchy of timescales naturally emerges from this system: sensory areas show brief, transient responses to input (appropriate for sensory processing), whereas association areas integrate inputs over time and exhibit persistent activity (suitable for decision-making and working memory). The model displays multiple temporal hierarchies, as evidenced by contrasting responses to visual versus somatosensory stimulation. Moreover, slower prefrontal and temporal areas have a disproportionate impact on global brain dynamics. These findings establish a circuit mechanism for "temporal receptive windows" that are progressively enlarged along the cortical hierarchy, suggest an extension of time integration in decision making from local to large circuits, and should prompt a re-evaluation of the analysis of functional connectivity (measured by fMRI or electroencephalography/magnetoencephalography) by taking into account inter-areal heterogeneity.
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Affiliation(s)
- Rishidev Chaudhuri
- Center for Neural Science, New York University, New York, NY 10003, USA; Center for Learning and Memory, University of Texas at Austin, Austin, TX 78712, USA
| | - Kenneth Knoblauch
- INSERM U846, Stem Cell and Brain Research Institute, 69500 Bron, France; Université de Lyon, Université Lyon I, 69003 Lyon, France
| | - Marie-Alice Gariel
- INSERM U846, Stem Cell and Brain Research Institute, 69500 Bron, France; Université de Lyon, Université Lyon I, 69003 Lyon, France
| | - Henry Kennedy
- INSERM U846, Stem Cell and Brain Research Institute, 69500 Bron, France; Université de Lyon, Université Lyon I, 69003 Lyon, France
| | - Xiao-Jing Wang
- Center for Neural Science, New York University, New York, NY 10003, USA; NYU-ECNU Institute of Brain and Cognitive Science, NYU Shanghai, Shanghai 200122, China.
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53
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Liu Y, Huang Y, Lee S, Bookout AL, Castorena CM, Wu H, Gautron L. PPARγ mRNA in the adult mouse hypothalamus: distribution and regulation in response to dietary challenges. Front Neuroanat 2015; 9:120. [PMID: 26388745 PMCID: PMC4558427 DOI: 10.3389/fnana.2015.00120] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 08/20/2015] [Indexed: 11/13/2022] Open
Abstract
Peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-activated transcription factor that was originally identified as a regulator of peroxisome proliferation and adipocyte differentiation. Emerging evidence suggests that functional PPARγ signaling also occurs within the hypothalamus. However, the exact distribution and identities of PPARγ-expressing hypothalamic cells remains under debate. The present study systematically mapped PPARγ mRNA expression in the adult mouse brain using in situ hybridization histochemistry. PPARγ mRNA was found to be expressed at high levels outside the hypothalamus including the neocortex, the olfactory bulb, the organ of the vasculosum of the lamina terminalis (VOLT), and the subfornical organ. Within the hypothalamus, PPARγ was present at moderate levels in the suprachiasmatic nucleus (SCh) and the ependymal of the 3rd ventricle. In all examined feeding-related hypothalamic nuclei, PPARγ was expressed at very low levels that were close to the limit of detection. Using qPCR techniques, we demonstrated that PPARγ mRNA expression was upregulated in the SCh in response to fasting. Double in situ hybridization further demonstrated that PPARγ was primarily expressed in neurons rather than glia. Collectively, our observations provide a comprehensive map of PPARγ distribution in the intact adult mouse hypothalamus.
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Affiliation(s)
- Yang Liu
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA ; Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology Wuhan, China
| | - Ying Huang
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Syann Lee
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Angie L Bookout
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Carlos M Castorena
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Hua Wu
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology Wuhan, China
| | - Laurent Gautron
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
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Mohan H, Verhoog MB, Doreswamy KK, Eyal G, Aardse R, Lodder BN, Goriounova NA, Asamoah B, B Brakspear ABC, Groot C, van der Sluis S, Testa-Silva G, Obermayer J, Boudewijns ZSRM, Narayanan RT, Baayen JC, Segev I, Mansvelder HD, de Kock CPJ. Dendritic and Axonal Architecture of Individual Pyramidal Neurons across Layers of Adult Human Neocortex. Cereb Cortex 2015; 25:4839-53. [PMID: 26318661 PMCID: PMC4635923 DOI: 10.1093/cercor/bhv188] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The size and shape of dendrites and axons are strong determinants of neuronal information processing. Our knowledge on neuronal structure and function is primarily based on brains of laboratory animals. Whether it translates to human is not known since quantitative data on "full" human neuronal morphologies are lacking. Here, we obtained human brain tissue during resection surgery and reconstructed basal and apical dendrites and axons of individual neurons across all cortical layers in temporal cortex (Brodmann area 21). Importantly, morphologies did not correlate to etiology, disease severity, or disease duration. Next, we show that human L(ayer) 2 and L3 pyramidal neurons have 3-fold larger dendritic length and increased branch complexity with longer segments compared with temporal cortex neurons from macaque and mouse. Unsupervised cluster analysis classified 88% of human L2 and L3 neurons into human-specific clusters distinct from mouse and macaque neurons. Computational modeling of passive electrical properties to assess the functional impact of large dendrites indicates stronger signal attenuation of electrical inputs compared with mouse. We thus provide a quantitative analysis of "full" human neuron morphologies and present direct evidence that human neurons are not "scaled-up" versions of rodent or macaque neurons, but have unique structural and functional properties.
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Affiliation(s)
- Hemanth Mohan
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Matthijs B Verhoog
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Keerthi K Doreswamy
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Guy Eyal
- Department of Neurobiology and Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Romy Aardse
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Brendan N Lodder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Natalia A Goriounova
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Boateng Asamoah
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - A B Clementine B Brakspear
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Colin Groot
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Sophie van der Sluis
- Department of Clinical Genetics, Section Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, VU Medical Center, Amsterdam, The Netherlands
| | - Guilherme Testa-Silva
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Joshua Obermayer
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Zimbo S R M Boudewijns
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Rajeevan T Narayanan
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Johannes C Baayen
- Department of Neurosurgery, VU University Medical Center, Amsterdam 1081 HV, The Netherlands
| | - Idan Segev
- Department of Neurobiology and Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
| | - Christiaan P J de Kock
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam 1081 HV, The Netherlands
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Rajtmajer SM, Roy A, Albert R, Molenaar PCM, Hillary FG. A voxelwise approach to determine consensus regions-of-interest for the study of brain network plasticity. Front Neuroanat 2015; 9:97. [PMID: 26283928 PMCID: PMC4517380 DOI: 10.3389/fnana.2015.00097] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Accepted: 07/07/2015] [Indexed: 11/13/2022] Open
Abstract
Despite exciting advances in the functional imaging of the brain, it remains a challenge to define regions of interest (ROIs) that do not require investigator supervision and permit examination of change in networks over time (or plasticity). Plasticity is most readily examined by maintaining ROIs constant via seed-based and anatomical-atlas based techniques, but these approaches are not data-driven, requiring definition based on prior experience (e.g., choice of seed-region, anatomical landmarks). These approaches are limiting especially when functional connectivity may evolve over time in areas that are finer than known anatomical landmarks or in areas outside predetermined seeded regions. An ideal method would permit investigators to study network plasticity due to learning, maturation effects, or clinical recovery via multiple time point data that can be compared to one another in the same ROI while also preserving the voxel-level data in those ROIs at each time point. Data-driven approaches (e.g., whole-brain voxelwise approaches) ameliorate concerns regarding investigator bias, but the fundamental problem of comparing the results between distinct data sets remains. In this paper we propose an approach, aggregate-initialized label propagation (AILP), which allows for data at separate time points to be compared for examining developmental processes resulting in network change (plasticity). To do so, we use a whole-brain modularity approach to parcellate the brain into anatomically constrained functional modules at separate time points and then apply the AILP algorithm to form a consensus set of ROIs for examining change over time. To demonstrate its utility, we make use of a known dataset of individuals with traumatic brain injury sampled at two time points during the first year of recovery and show how the AILP procedure can be applied to select regions of interest to be used in a graph theoretical analysis of plasticity.
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Affiliation(s)
- Sarah M Rajtmajer
- Department of Mathematics, The Pennsylvania State University University Park, PA, USA
| | - Arnab Roy
- Department of Psychology, The Pennsylvania State University University Park, PA, USA
| | - Reka Albert
- Department of Physics, The Pennsylvania State University University Park, PA, USA
| | - Peter C M Molenaar
- Department of Human Development and Family Studies, The Pennsylvania State University University Park, PA, USA
| | - Frank G Hillary
- Department of Psychology, The Pennsylvania State University University Park, PA, USA ; Department of Neurology, Penn State Milton S. Hershey Medical Center Hershey, PA, USA
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56
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Ramaswamy S, Markram H. Anatomy and physiology of the thick-tufted layer 5 pyramidal neuron. Front Cell Neurosci 2015; 9:233. [PMID: 26167146 PMCID: PMC4481152 DOI: 10.3389/fncel.2015.00233] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 06/08/2015] [Indexed: 11/13/2022] Open
Abstract
The thick-tufted layer 5 (TTL5) pyramidal neuron is one of the most extensively studied neuron types in the mammalian neocortex and has become a benchmark for understanding information processing in excitatory neurons. By virtue of having the widest local axonal and dendritic arborization, the TTL5 neuron encompasses various local neocortical neurons and thereby defines the dimensions of neocortical microcircuitry. The TTL5 neuron integrates input across all neocortical layers and is the principal output pathway funneling information flow to subcortical structures. Several studies over the past decades have investigated the anatomy, physiology, synaptology, and pathophysiology of the TTL5 neuron. This review summarizes key discoveries and identifies potential avenues of research to facilitate an integrated and unifying understanding on the role of a central neuron in the neocortex.
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Affiliation(s)
- Srikanth Ramaswamy
- Blue Brain Project, Ecole Polytechnique Fédérale de Lausanne, Campus Biotech Geneva, Switzerland
| | - Henry Markram
- Blue Brain Project, Ecole Polytechnique Fédérale de Lausanne, Campus Biotech Geneva, Switzerland
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57
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Abstract
Despite the attention attracted by “connectomics”, one can lose sight of the very real questions concerning “What are connections?” In the neuroimaging community, “structural” connectivity is ground truth and underlying constraint on “functional” or “effective” connectivity. It is referenced to underlying anatomy; but, as increasingly remarked, there is a large gap between the wealth of human brain mapping and the relatively scant data on actual anatomical connectivity. Moreover, connections have typically been discussed as “pairwise”, point x projecting to point y (or: to points y and z), or more recently, in graph theoretical terms, as “nodes” or regions and the interconnecting “edges”. This is a convenient shorthand, but tends not to capture the richness and nuance of basic anatomical properties as identified in the classic tradition of tracer studies. The present short review accordingly revisits connectional weights, heterogeneity, reciprocity, topography, and hierarchical organization, drawing on concrete examples. The emphasis is on presynaptic long-distance connections, motivated by the intention to probe current assumptions and promote discussions about further progress and synthesis.
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Affiliation(s)
- Kathleen S Rockland
- Department of Anatomy and Neurobiology, Boston University School of Medicine Boston, MA, USA ; Cold Spring Harbor Laboratory, Cold Spring Harbor NY, USA
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58
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Arteaga G, Buritica E, Escobar MI, Pimienta H. Human prefrontal layer II interneurons in areas 46, 10 and 24. Colomb Med (Cali) 2015; 46:19-25. [PMID: 26019381 PMCID: PMC4437283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 12/10/2014] [Accepted: 02/02/2015] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Prefrontal cortex (PFC) represents the highest level of integration and control of psychic and behavioral states. Several dysfunctions such as autism, hyperactivity disorders, depression, and schizophrenia have been related with alterations in the prefrontal cortex (PFC). Among the cortical layers of the PFC, layer II shows a particular vertical pattern of organization, the highest cell density and the biggest non-pyramidal/pyramidal neuronal ratio. We currently characterized the layer II cytoarchitecture in human areas 10, 24, and 46. OBJECTIVE We focused particularly on the inhibitory neurons taking into account that these cells are involved in sustained firing (SF) after stimuli disappearance. METHODS Postmortem samples from five subjects who died by causes different to central nervous system diseases were studied. Immunohistochemistry for the neuronal markers, NeuN, parvalbumin (PV), calbindin (CB), and calretinin (CR) were used. NeuN targeted the total neuronal population while the rest of the markers specifically the interneurons. RESULTS Cell density and soma size were statically different between areas 10, 46, 24 when using NeuN. Layer II of area 46 showed the highest cell density. Regarding interneurons, PV+-cells of area 46 showed the highest density and size, in accordance to the proposal of a dual origin of the cerebral cortex. Interhemispheric asymmetries were not identified between homologue areas. CONCLUSION First, our findings suggest that layer II of area 46 exhibits the most powerful inhibitory system compared to the other prefrontal areas analyzed. This feature is not only characteristic of the PFC but also supports a particular role of layer II of area 46 in SF. Additionally, known functional asymmetries between hemispheres might not be supported by morphological asymmetries.
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Affiliation(s)
| | | | | | - Hernan Pimienta
- Centro de Estudios Cerebrales, Facultad de Salud, Universidad del Valle, Cali, Colombia
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Böhm MRR, Melkonyan H, Thanos S. Life-time expression of the proteins peroxiredoxin, beta-synuclein, PARK7/DJ-1, and stathmin in the primary visual and primary somatosensory cortices in rats. Front Neuroanat 2015; 9:16. [PMID: 25788877 PMCID: PMC4349188 DOI: 10.3389/fnana.2015.00016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 02/04/2015] [Indexed: 11/16/2022] Open
Abstract
Four distinct proteins are regulated in the aging neuroretina and may be regulated in the cerebral cortex, too: peroxiredoxin, beta-synuclein, PARK[Parkinson disease(autosomal recessive, early onset)]7/DJ-1, and Stathmin. Thus, we performed a comparative analysis of these proteins in the the primary somatosensory cortex (S1) and primary visual cortex (V1) in rats, in order to detect putative common development-, maturation- and age-related changes. The expressions of peroxiredoxin, beta-synuclein, PARK[Parkinson disease (autosomal recessive, early onset)]7/DJ-1, and Stathmin were compared in the newborn, juvenile, adult, and aged S1 and V1. Western blot (WB), quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and immunohistochemistry (IHC) analyses were employed to determine whether the changes identified by proteomics were verifiable at the cellular and molecular levels. All of the proteins were detected in both of the investigated cortical areas. Changes in the expressions of the four proteins were found throughout the life-time of the rats. Peroxiredoxin expression remained unchanged over life-time. Beta-Synuclein expression was massively increased up to the adult stage of life in both the S1 and V1. PARK[Parkinson disease (autosomal recessive, early onset)]7/DJ-1 exhibited a massive up-regulation in both the S1 and V1 at all ages. Stathmin expression was massively down regulated after the neonatal period in both the S1 and V1. The detected protein alterations were analogous to their retinal profiles. This study is the first to provide evidence that peroxiredoxin, beta-synuclein, PARK[Parkinson disease (autosomal recessive, early onset)]7/DJ-1, and Stathmin are associated with postnatal maturation and aging in both the S1 and V1 of rats. These changes may indicate their involvement in key functional pathways and may account for the onset or progression of age-related pathologies.
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Affiliation(s)
- Michael R R Böhm
- Institute of Experimental Ophthalmology and DFG-Center of Excellence Cells in Motion (CiM), area C.4, School of Medicine, Westfalian-Wilhelms-University of Münster Münster, Germany ; Department of Ophthalmology, St. Franziskus Hospital Münster Münster, Germany
| | - Harutyun Melkonyan
- Institute of Experimental Ophthalmology and DFG-Center of Excellence Cells in Motion (CiM), area C.4, School of Medicine, Westfalian-Wilhelms-University of Münster Münster, Germany
| | - Solon Thanos
- Institute of Experimental Ophthalmology and DFG-Center of Excellence Cells in Motion (CiM), area C.4, School of Medicine, Westfalian-Wilhelms-University of Münster Münster, Germany
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Rotaru DC, Olezene C, Miyamae T, Povysheva NV, Zaitsev AV, Lewis DA, Gonzalez-Burgos G. Functional properties of GABA synaptic inputs onto GABA neurons in monkey prefrontal cortex. J Neurophysiol 2015; 113:1850-61. [PMID: 25540225 PMCID: PMC4359991 DOI: 10.1152/jn.00799.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 12/23/2014] [Indexed: 11/22/2022] Open
Abstract
In rodent cortex GABAA receptor (GABAAR)-mediated synapses are a significant source of input onto GABA neurons, and the properties of these inputs vary among GABA neuron subtypes that differ in molecular markers and firing patterns. Some features of cortical interneurons are different between rodents and primates, but it is not known whether inhibition of GABA neurons is prominent in the primate cortex and, if so, whether these inputs show heterogeneity across GABA neuron subtypes. We thus studied GABAAR-mediated miniature synaptic events in GABAergic interneurons in layer 3 of monkey dorsolateral prefrontal cortex (DLPFC). Interneurons were identified on the basis of their firing pattern as fast spiking (FS), regular spiking (RS), burst spiking (BS), or irregular spiking (IS). Miniature synaptic events were common in all of the recorded interneurons, and the frequency of these events was highest in FS neurons. The amplitude and kinetics of miniature inhibitory postsynaptic potentials (mIPSPs) also differed between DLPFC interneuron subtypes in a manner correlated with their input resistance and membrane time constant. FS neurons had the fastest mIPSP decay times and the strongest effects of the GABAAR modulator zolpidem, suggesting that the distinctive properties of inhibitory synaptic inputs onto FS cells are in part conferred by GABAARs containing α1 subunits. Moreover, mIPSCs differed between FS and RS interneurons in a manner consistent with the mIPSP findings. These results show that in the monkey DLPFC GABAAR-mediated synaptic inputs are prominent in layer 3 interneurons and may differentially regulate the activity of different interneuron subtypes.
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Affiliation(s)
- Diana C Rotaru
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Cameron Olezene
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Takeaki Miyamae
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Nadezhda V Povysheva
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Aleksey V Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, St. Petersburg, Russia
| | - David A Lewis
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Guillermo Gonzalez-Burgos
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania;
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Mancuso JJ, Cheng J, Yin Z, Gilliam JC, Xia X, Li X, Wong STC. Integration of multiscale dendritic spine structure and function data into systems biology models. Front Neuroanat 2014; 8:130. [PMID: 25429262 PMCID: PMC4228840 DOI: 10.3389/fnana.2014.00130] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 10/22/2014] [Indexed: 12/27/2022] Open
Abstract
Comprising 1011 neurons with 1014 synaptic connections the human brain is the ultimate systems biology puzzle. An increasing body of evidence highlights the observation that changes in brain function, both normal and pathological, consistently correlate with dynamic changes in neuronal anatomy. Anatomical changes occur on a full range of scales from the trafficking of individual proteins, to alterations in synaptic morphology both individually and on a systems level, to reductions in long distance connectivity and brain volume. The major sites of contact for synapsing neurons are dendritic spines, which provide an excellent metric for the number and strength of signaling connections between elements of functional neuronal circuits. A comprehensive model of anatomical changes and their functional consequences would be a holy grail for the field of systems neuroscience but its realization appears far on the horizon. Various imaging technologies have advanced to allow for multi-scale visualization of brain plasticity and pathology, but computational analysis of the big data sets involved forms the bottleneck toward the creation of multiscale models of brain structure and function. While a full accounting of techniques and progress toward a comprehensive model of brain anatomy and function is beyond the scope of this or any other single paper, this review serves to highlight the opportunities for analysis of neuronal spine anatomy and function provided by new imaging technologies and the high-throughput application of older technologies while surveying the strengths and weaknesses of currently available computational analytical tools and room for future improvement.
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Affiliation(s)
- James J Mancuso
- Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute Houston, TX, USA ; TT and WF Chao Center for Bioinformatics Research and Imaging for Neurosciences, Houston Methodist Research Institute Houston, TX, USA
| | - Jie Cheng
- Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute Houston, TX, USA ; TT and WF Chao Center for Bioinformatics Research and Imaging for Neurosciences, Houston Methodist Research Institute Houston, TX, USA
| | - Zheng Yin
- Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute Houston, TX, USA ; TT and WF Chao Center for Bioinformatics Research and Imaging for Neurosciences, Houston Methodist Research Institute Houston, TX, USA
| | - Jared C Gilliam
- Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute Houston, TX, USA ; TT and WF Chao Center for Bioinformatics Research and Imaging for Neurosciences, Houston Methodist Research Institute Houston, TX, USA
| | - Xiaofeng Xia
- Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute Houston, TX, USA ; TT and WF Chao Center for Bioinformatics Research and Imaging for Neurosciences, Houston Methodist Research Institute Houston, TX, USA
| | - Xuping Li
- Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute Houston, TX, USA ; TT and WF Chao Center for Bioinformatics Research and Imaging for Neurosciences, Houston Methodist Research Institute Houston, TX, USA
| | - Stephen T C Wong
- Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute Houston, TX, USA ; TT and WF Chao Center for Bioinformatics Research and Imaging for Neurosciences, Houston Methodist Research Institute Houston, TX, USA
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62
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Linking macroscale graph analytical organization to microscale neuroarchitectonics in the macaque connectome. J Neurosci 2014; 34:12192-205. [PMID: 25186762 DOI: 10.1523/jneurosci.0752-14.2014] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Macroscale connectivity of the mammalian brain has been shown to display several characteristics of an efficient communication network architecture. In parallel, at the microscopic scale, histological studies have extensively revealed large interregional variation in cortical neural architectonics. However, how these two "scales" of cerebrum organization are linked remains an open question. Collating and combining data across multiple studies on the cortical cytoarchitecture of the macaque cortex with information on macroscale anatomical wiring derived from tract tracing studies, this study focuses on examining the interplay between macroscale organization of the macaque connectome and microscale cortical neuronal architecture. Our findings show that both macroscale degree as well as the topological role in the overall network are related to the level of neuronal complexity of cortical regions at the microscale, showing (among several effects) a positive overall association between macroscale degree and metrics of microscale pyramidal complexity. Macroscale hub regions, together forming a densely interconnected "rich club," are noted to display a high level of neuronal complexity, findings supportive of a high level of integrative neuronal processes to occur in these regions. Together, we report on cross-scale observations that jointly suggest that a region's microscale neuronal architecture is tuned to its role in the global brain network.
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63
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Džaja D, Hladnik A, Bičanić I, Baković M, Petanjek Z. Neocortical calretinin neurons in primates: increase in proportion and microcircuitry structure. Front Neuroanat 2014; 8:103. [PMID: 25309344 PMCID: PMC4174738 DOI: 10.3389/fnana.2014.00103] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 09/07/2014] [Indexed: 12/04/2022] Open
Abstract
In this article we first point at the expansion of associative cortical areas in primates, as well as at the intrinsic changes in the structure of the cortical column. There is a huge increase in proportion of glutamatergic cortical projecting neurons located in the upper cortical layers (II/III). Inside this group, a novel class of associative neurons becomes recognized for its growing necessity in both inter-areal and intra-areal columnar integration. Equally important to the changes in glutamatergic population, we found that literature data suggest a 50% increase in the proportion of neocortical GABAergic neurons between primates and rodents. This seems to be a result of increase in proportion of calretinin interneurons in layers II/III, population which in associative areas represents 15% of all neurons forming those layers. Evaluating data about functional properties of their connectivity we hypothesize that such an increase in proportion of calretinin interneurons might lead to supra-linear growth in memory capacity of the associative neocortical network. An open question is whether there are some new calretinin interneuron subtypes, which might substantially change micro-circuitry structure of the primate cerebral cortex.
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Affiliation(s)
- Domagoj Džaja
- Laboratory for Neuromorphometry, Department of Neuroscience, Croatian Institute for Brain Research, School of Medicine, University of Zagreb Zagreb, Croatia
| | - Ana Hladnik
- Department of Anatomy and Clinical Anatomy, School of Medicine, University of Zagreb Zagreb, Croatia
| | - Ivana Bičanić
- Department of Anatomy and Clinical Anatomy, School of Medicine, University of Zagreb Zagreb, Croatia
| | - Marija Baković
- Institute of Forensic Medicine and Criminalistics, School of Medicine, University of Zagreb Zagreb, Croatia
| | - Zdravko Petanjek
- Laboratory for Neuromorphometry, Department of Neuroscience, Croatian Institute for Brain Research, School of Medicine, University of Zagreb Zagreb, Croatia ; Department of Anatomy and Clinical Anatomy, School of Medicine, University of Zagreb Zagreb, Croatia
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64
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Charvet CJ, Finlay BL. Evo-devo and the primate isocortex: the central organizing role of intrinsic gradients of neurogenesis. BRAIN, BEHAVIOR AND EVOLUTION 2014; 84:81-92. [PMID: 25247448 DOI: 10.1159/000365181] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Spatial gradients in the initiation and termination of basic processes, such as cytogenesis, cell-type specification and dendritic maturation, are ubiquitous in developing nervous systems. Such gradients can produce a niche adaptation in a particular species. For example, the high density of photoreceptors and neurons in the 'area centralis' of some vertebrate retinas result from the early maturation of its center relative to its periphery. Across species, regularities in allometric scaling of brain regions can derive from conserved spatial gradients: longer neurogenesis in the alar versus the basal plate of the neural tube is associated with relatively greater expansion of alar plate derivatives in larger brains. We describe gradients of neurogenesis within the isocortex and their effects on adult cytoarchitecture within and across species. Longer duration of neurogenesis in the caudal isocortex is associated with increased neuron number and density per column relative to the rostral isocortex. Later-maturing features of single neurons, such as soma size and dendritic spine numbers reflect this gradient. Considering rodents and primates, the longer the duration of isocortical neurogenesis in each species, the greater the rostral-to-caudal difference in neuron number and density per column. Extended developmental duration produces substantial, predictable changes in the architecture of the isocortex in larger brains, and presumably a progressively changed functional organization, the properties of which we do not yet fully understand. Many features of isocortical architecture previously viewed as species- or niche-specific adaptations can now be integrated as the natural outcomes of spatiotemporal gradients that are deployed in larger brains.
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Affiliation(s)
- Christine J Charvet
- Behavioral and Evolutionary Neuroscience Group, Department of Psychology, Cornell University, Ithaca, N.Y., USA
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65
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Elston GN, Fujita I. Pyramidal cell development: postnatal spinogenesis, dendritic growth, axon growth, and electrophysiology. Front Neuroanat 2014; 8:78. [PMID: 25161611 PMCID: PMC4130200 DOI: 10.3389/fnana.2014.00078] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 07/22/2014] [Indexed: 01/12/2023] Open
Abstract
Here we review recent findings related to postnatal spinogenesis, dendritic and axon growth, pruning and electrophysiology of neocortical pyramidal cells in the developing primate brain. Pyramidal cells in sensory, association and executive cortex grow dendrites, spines and axons at different rates, and vary in the degree of pruning. Of particular note is the fact that pyramidal cells in primary visual area (V1) prune more spines than they grow during postnatal development, whereas those in inferotemporal (TEO and TE) and granular prefrontal cortex (gPFC; Brodmann's area 12) grow more than they prune. Moreover, pyramidal cells in TEO, TE and the gPFC continue to grow larger dendritic territories from birth into adulthood, replete with spines, whereas those in V1 become smaller during this time. The developmental profile of intrinsic axons also varies between cortical areas: those in V1, for example, undergo an early proliferation followed by pruning and local consolidation into adulthood, whereas those in area TE tend to establish their territory and consolidate it into adulthood with little pruning. We correlate the anatomical findings with the electrophysiological properties of cells in the different cortical areas, including membrane time constant, depolarizing sag, duration of individual action potentials, and spike-frequency adaptation. All of the electrophysiological variables ramped up before 7 months of age in V1, but continued to ramp up over a protracted period of time in area TE. These data suggest that the anatomical and electrophysiological profiles of pyramidal cells vary among cortical areas at birth, and continue to diverge into adulthood. Moreover, the data reveal that the “use it or lose it” notion of synaptic reinforcement may speak to only part of the story, “use it but you still might lose it” may be just as prevalent in the cerebral cortex.
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Affiliation(s)
- Guy N Elston
- Centre for Cognitive Neuroscience Sunshine Coast, QLD, Australia
| | - Ichiro Fujita
- Graduate School of Frontier Biosciences and Center for Information and Neural Networks, Osaka University and National Institute of Communication Technology Suita, Japan
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66
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de Sousa AA, Proulx MJ. What can volumes reveal about human brain evolution? A framework for bridging behavioral, histometric, and volumetric perspectives. Front Neuroanat 2014; 8:51. [PMID: 25009469 PMCID: PMC4069365 DOI: 10.3389/fnana.2014.00051] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Accepted: 06/03/2014] [Indexed: 11/25/2022] Open
Abstract
An overall relationship between brain size and cognitive ability exists across primates. Can more specific information about neural function be gleaned from cortical area volumes? Numerous studies have found significant relationships between brain structures and behaviors. However, few studies have speculated about brain structure-function relationships from the microanatomical to the macroanatomical level. Here we address this problem in comparative neuroanatomy, where the functional relevance of overall brain size and the sizes of cortical regions have been poorly understood, by considering comparative psychology, with measures of visual acuity and the perception of visual illusions. We outline a model where the macroscopic size (volume or surface area) of a cortical region (such as the primary visual cortex, V1) is related to the microstructure of discrete brain regions. The hypothesis developed here is that an absolutely larger V1 can process more information with greater fidelity due to having more neurons to represent a field of space. This is the first time that the necessary comparative neuroanatomical research at the microstructural level has been brought to bear on the issue. The evidence suggests that as the size of V1 increases: the number of neurons increases, the neuron density decreases, and the density of neuronal connections increases. Thus, we describe how information about gross neuromorphology, using V1 as a model for the study of other cortical areas, may permit interpretations of cortical function.
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Affiliation(s)
| | - Michael J Proulx
- Crossmodal Cognition Lab, Department of Psychology, University of Bath Bath, UK
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67
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Karbowski J. Constancy and trade-offs in the neuroanatomical and metabolic design of the cerebral cortex. Front Neural Circuits 2014; 8:9. [PMID: 24574975 PMCID: PMC3920482 DOI: 10.3389/fncir.2014.00009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 01/23/2014] [Indexed: 12/13/2022] Open
Abstract
Mammalian brains span about four orders of magnitude in cortical volume and have to operate in different environments that require diverse behavioral skills. Despite these geometric and behavioral diversities, the examination of cerebral cortex across species reveals that it contains a substantial number of conserved characteristics that are associated with neuroanatomy and metabolism, i.e., with neuronal connectivity and function. Some of these cortical constants or invariants have been known for a long time but not sufficiently appreciated, and others were only recently discovered. The focus of this review is to present the cortical invariants and discuss their role in the efficient information processing. Global conservation in neuroanatomy and metabolism, as well as their correlated regional and developmental variability suggest that these two parallel systems are mutually coupled. It is argued that energetic constraint on cortical organization can be strong if cerebral blood supplied is either below or above a certain level, and it is rather soft otherwise. Moreover, because maximization or minimization of parameters associated with cortical connectivity, function and cost often leads to conflicts in design, it is argued that the architecture of the cerebral cortex is a result of structural and functional compromises.
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Affiliation(s)
- Jan Karbowski
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences Warsaw, Poland ; Department of Mathematics, Informatics and Mechanics, Institute of Applied Mathematics and Mechanics, University of Warsaw Warsaw, Poland ; Division of Biology Caltech, Pasadena, CA, USA
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68
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Marín-Padilla M. The mammalian neocortex new pyramidal neuron: a new conception. Front Neuroanat 2014; 7:51. [PMID: 24431992 PMCID: PMC3880895 DOI: 10.3389/fnana.2013.00051] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 12/19/2013] [Indexed: 11/13/2022] Open
Abstract
The new cerebral cortex (neocortex) and the new type of pyramidal neuron are mammalian innovations that have evolved for operating their increasing motor capabilities while essentially using analogous anatomical and neural makeups. The human neocortex starts to develop in 6-week-old embryos with the establishment of a primordial cortical organization, which resembles the primitive cortices of amphibian and reptiles. From the 8th to the 15th week of age, new pyramidal neurons, of ependymal origin, are progressively incorporated within this primordial cortex forming a cellular plate that divides its components into those above it (neocortex first layer) and those below it (neocortex subplate zone). From the 16th week of age to birth and postnatally, the new pyramidal neurons continue to elongate functionally their apical dendrite by adding synaptic membrane to incorporate the needed sensory information for operating its developing motor activities. The new pyramidal neuron' distinguishing feature is the capacity of elongating anatomically and functionally its apical dendrite (its main receptive surface) without losing its original attachment to first layer or the location of its soma and, hence, retaining its essential nature. The number of pyramidal cell functional strata established in the motor cortex increases and reflects each mammalian species motor capabilities: the hedgehog needs two pyramidal cell functional strata to carry out all its motor activities, the mouse 3, cat 4, primates 5 and humans 6. The presence of six pyramidal cell functional strata distinguish the human motor cortex from that of others primates. Homo sapiens represent a new evolutionary stage that have transformed his primate brain for operating his unique motor capabilities, such as speaking, writing, painting, sculpturing and thinking as a premotor activity. Words used in language are the motor expression of thoughts and represent sounds produced by maneuvering the column of expiratory air by coordinated motor quivering as it passes through the larynx, pharynx, mouth, tongue, and lips. Homo sapiens cerebrum has developed new motor centers to communicate mental thoughts (and/or intention) through motor actions.
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Affiliation(s)
- Miguel Marín-Padilla
- Department of Pathology and Pediatrics, The Geisel School of Medicine at DartmouthHanover, NH USA
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69
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Bianchi S, Stimpson CD, Bauernfeind AL, Schapiro SJ, Baze WB, McArthur MJ, Bronson E, Hopkins WD, Semendeferi K, Jacobs B, Hof PR, Sherwood CC. Dendritic morphology of pyramidal neurons in the chimpanzee neocortex: regional specializations and comparison to humans. Cereb Cortex 2013; 23:2429-36. [PMID: 22875862 PMCID: PMC3767963 DOI: 10.1093/cercor/bhs239] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The primate cerebral cortex is characterized by regional variation in the structure of pyramidal neurons, with more complex dendritic arbors and greater spine density observed in prefrontal compared with sensory and motor cortices. Although there are several investigations in humans and other primates, virtually nothing is known about regional variation in the morphology of pyramidal neurons in the cerebral cortex of great apes, humans' closest living relatives. The current study uses the rapid Golgi stain to quantify the dendritic structure of layer III pyramidal neurons in 4 areas of the chimpanzee cerebral cortex: Primary somatosensory (area 3b), primary motor (area 4), prestriate visual (area 18), and prefrontal (area 10) cortex. Consistent with previous studies in humans and macaque monkeys, pyramidal neurons in the prefrontal cortex of chimpanzees exhibit greater dendritic complexity than those in other cortical regions, suggesting that prefrontal cortical evolution in primates is characterized by increased potential for integrative connectivity. Compared with chimpanzees, the pyramidal neurons of humans had significantly longer and more branched dendritic arbors in all cortical regions.
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Affiliation(s)
- Serena Bianchi
- Department of Anthropology, The George Washington University, Washington, DC
| | - Cheryl D. Stimpson
- Department of Anthropology, The George Washington University, Washington, DC
| | - Amy L. Bauernfeind
- Department of Anthropology, The George Washington University, Washington, DC
| | - Steven J. Schapiro
- Department of Veterinary Sciences, The University of Texas M.D. Anderson Cancer Center, Bastrop, TX 78602
| | - Wallace B. Baze
- Department of Veterinary Sciences, The University of Texas M.D. Anderson Cancer Center, Bastrop, TX 78602
| | - Mark J. McArthur
- Department of Veterinary Sciences, The University of Texas M.D. Anderson Cancer Center, Bastrop, TX 78602
| | | | - William D. Hopkins
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30302
- Division of Developmental and Cognitive Neuroscience, Yerkes National Primate Research Center, Atlanta, GA 30322
| | - Katerina Semendeferi
- Department of Anthropology and Neuroscience Graduate Program, University of California, San Diego, La Jolla, CA 92093
| | - Bob Jacobs
- Department of Psychology, Colorado College, Colorado Springs, CO 80903
| | - Patrick R. Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Mount Sinai School of Medicine, New York, NY 10029 and
- New York Consortium in Evolutionary Primatology, New York, NY, USA
| | - Chet C. Sherwood
- Department of Anthropology, The George Washington University, Washington, DC
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70
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Katsuki F, Qi XL, Meyer T, Kostelic PM, Salinas E, Constantinidis C. Differences in intrinsic functional organization between dorsolateral prefrontal and posterior parietal cortex. Cereb Cortex 2013; 24:2334-49. [PMID: 23547137 DOI: 10.1093/cercor/bht087] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The dorsolateral prefrontal and posterior parietal cortex are 2 components of the cortical network controlling attention, working memory, and executive function. Little is known about how the anatomical organization of the 2 areas accounts for their functional specialization. In order to address this question, we examined the strength of intrinsic functional connectivity between neurons sampled in each area by means of cross-correlation analyses of simultaneous recordings from monkeys trained to perform working memory tasks. In both areas, effective connectivity declined as a function of distance between neurons. However, the strength of effective connectivity was higher overall and more localized over short distances in the posterior parietal than the prefrontal cortex. The difference in connectivity strength between the 2 areas could not be explained by differences in firing rate or selectivity for the stimuli and task events, it was present when the fixation period alone was analyzed, and according to simulation results, was consistent with a systematic difference either in the strength or in the relative numbers of shared inputs between neurons. Our results indicate that the 2 areas are characterized by unique intrinsic functional organization, consistent with known differences in their response patterns during working memory.
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Affiliation(s)
- Fumi Katsuki
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Xue-Lian Qi
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Travis Meyer
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Phillip M Kostelic
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Emilio Salinas
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Christos Constantinidis
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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Benavides-Piccione R, Fernaud-Espinosa I, Robles V, Yuste R, DeFelipe J. Age-based comparison of human dendritic spine structure using complete three-dimensional reconstructions. ACTA ACUST UNITED AC 2012; 23:1798-810. [PMID: 22710613 DOI: 10.1093/cercor/bhs154] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Dendritic spines of pyramidal neurons are targets of most excitatory synapses in the cerebral cortex. Recent evidence suggests that the morphology of the dendritic spine could determine its synaptic strength and learning rules. However, unfortunately, there are scant data available regarding the detailed morphology of these structures for the human cerebral cortex. In the present study, we analyzed over 8900 individual dendritic spines that were completely 3D reconstructed along the length of apical and basal dendrites of layer III pyramidal neurons in the cingulate cortex of 2 male humans (aged 40 and 85 years old), using intracellular injections of Lucifer Yellow in fixed tissue. We assembled a large, quantitative database, which revealed a major reduction in spine densities in the aged case. Specifically, small and short spines of basal dendrites and long spines of apical dendrites were lost, regardless of the distance from the soma. Given the age difference between the cases, our results suggest selective alterations in spines with aging in humans and indicate that the spine volume and length are regulated by different biological mechanisms.
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72
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Extraordinary neoteny of synaptic spines in the human prefrontal cortex. Proc Natl Acad Sci U S A 2011; 108:13281-6. [PMID: 21788513 DOI: 10.1073/pnas.1105108108] [Citation(s) in RCA: 869] [Impact Index Per Article: 66.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The major mechanism for generating diversity of neuronal connections beyond their genetic determination is the activity-dependent stabilization and selective elimination of the initially overproduced synapses [Changeux JP, Danchin A (1976) Nature 264:705-712]. The largest number of supranumerary synapses has been recorded in the cerebral cortex of human and nonhuman primates. It is generally accepted that synaptic pruning in the cerebral cortex, including prefrontal areas, occurs at puberty and is completed during early adolescence [Huttenlocher PR, et al. (1979) Brain Res 163:195-205]. In the present study we analyzed synaptic spine density on the dendrites of layer IIIC cortico-cortical and layer V cortico-subcortical projecting pyramidal neurons in a large sample of human prefrontal cortices in subjects ranging in age from newborn to 91 y. We confirm that dendritic spine density in childhood exceeds adult values by two- to threefold and begins to decrease during puberty. However, we also obtained evidence that overproduction and developmental remodeling, including substantial elimination of synaptic spines, continues beyond adolescence and throughout the third decade of life before stabilizing at the adult level. Such an extraordinarily long phase of developmental reorganization of cortical neuronal circuitry has implications for understanding the effect of environmental impact on the development of human cognitive and emotional capacities as well as the late onset of human-specific neuropsychiatric disorders.
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