1
|
Sánchez-Ventura J, Lane MA, Udina E. The Role and Modulation of Spinal Perineuronal Nets in the Healthy and Injured Spinal Cord. Front Cell Neurosci 2022; 16:893857. [PMID: 35669108 PMCID: PMC9163449 DOI: 10.3389/fncel.2022.893857] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/21/2022] [Indexed: 11/13/2022] Open
Abstract
Rather than being a stable scaffold, perineuronal nets (PNNs) are a dynamic and specialized extracellular matrix involved in plasticity modulation. They have been extensively studied in the brain and associated with neuroprotection, ionic buffering, and neural maturation. However, their biological function in the spinal cord and the effects of disrupting spinal PNNs remain elusive. The goal of this review is to summarize the current knowledge of spinal PNNs and their potential in pathological conditions such as traumatic spinal cord injury (SCI). We also highlighted interventions that have been used to modulate the extracellular matrix after SCI, targeting the glial scar and spinal PNNs, in an effort to promote regeneration and stabilization of the spinal circuits, respectively. These concepts are discussed in the framework of developmental and neuroplastic changes in PNNs, drawing similarities between immature and denervated neurons after an SCI, which may provide a useful context for future SCI research.
Collapse
Affiliation(s)
- Judith Sánchez-Ventura
- Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
| | - Michael A. Lane
- Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA, United States
- The Marion Murray Spinal Cord Research Center, College of Medicine, Drexel University, Philadelphia, PA, United States
| | - Esther Udina
- Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
- *Correspondence: Esther Udina
| |
Collapse
|
2
|
Beebe NL, Schofield BR. Cholinergic boutons are closely associated with excitatory cells and four subtypes of inhibitory cells in the inferior colliculus. J Chem Neuroanat 2021; 116:101998. [PMID: 34186203 DOI: 10.1016/j.jchemneu.2021.101998] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 01/23/2023]
Abstract
Acetylcholine (ACh) is a neuromodulator that has been implicated in multiple roles across the brain, including the central auditory system, where it sets neuronal excitability and gain and affects plasticity. In the cerebral cortex, subtypes of GABAergic interneurons are modulated by ACh in a subtype-specific manner. Subtypes of GABAergic neurons have also begun to be described in the inferior colliculus (IC), a midbrain hub of the auditory system. Here, we used male and female mice (Mus musculus) that express fluorescent protein in cholinergic cells, axons, and boutons to look at the association between ACh and four subtypes of GABAergic IC cells that differ in their associations with extracellular markers, their soma sizes, and their distribution within the IC. We found that most IC cells, including excitatory and inhibitory cells, have cholinergic boutons closely associated with their somas and proximal dendrites. We also found that similar proportions of each of four subtypes of GABAergic cells are closely associated with cholinergic boutons. Whether the different types of GABAergic cells in the IC are differentially regulated remains unclear, as the response of cells to ACh is dependent on which types of ACh receptors are present. Additionally, this study confirms the presence of these four subtypes of GABAergic cells in the mouse IC, as they had previously been identified only in guinea pigs. These results suggest that cholinergic projections to the IC modulate auditory processing via direct effects on a multitude of inhibitory circuits.
Collapse
Affiliation(s)
- Nichole L Beebe
- Hearing Research Focus Group, Northeast Ohio Medical University, Rootstown, OH, USA; Brain Health Research Institute, Kent State University, Kent, OH, USA.
| | - Brett R Schofield
- Hearing Research Focus Group, Northeast Ohio Medical University, Rootstown, OH, USA; Brain Health Research Institute, Kent State University, Kent, OH, USA.
| |
Collapse
|
3
|
Beebe NL, Schofield BR. Perineuronal nets in subcortical auditory nuclei of four rodent species with differing hearing ranges. J Comp Neurol 2018; 526:972-989. [PMID: 29277975 DOI: 10.1002/cne.24383] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 11/20/2017] [Accepted: 12/09/2017] [Indexed: 12/19/2022]
Abstract
Perineuronal nets (PNs) are aggregates of extracellular matrix molecules that surround some neurons in the brain. While PNs occur widely across many cortical areas, subcortical PNs are especially associated with motor and auditory systems. The auditory system has recently been suggested as an ideal model system for studying PNs and their functions. However, descriptions of PNs in subcortical auditory areas vary, and it is unclear whether the variation reflects species differences or differences in staining techniques. Here, we used two staining techniques (one lectin stain and one antibody stain) to examine PN distribution in the subcortical auditory system of four different species: guinea pigs (Cavia porcellus), mice (Mus musculus, CBA/CaJ strain), Long-Evans rats (Rattus norvegicus), and naked mole-rats (Heterocephalus glaber). We found that some auditory nuclei exhibit dramatic differences in PN distribution among species while other nuclei have consistent PN distributions. We also found that PNs exhibit molecular heterogeneity, and can stain with either marker individually or with both. PNs within a given nucleus can be heterogeneous or homogenous in their staining patterns. We compared PN staining across the frequency axes of tonotopically organized nuclei and among species with different hearing ranges. PNs were distributed non-uniformly across some nuclei, but only rarely did this appear related to the tonotopic axis. PNs were prominent in all four species; we found no systematic relationship between the hearing range and the number, staining patterns or distribution of PNs in the auditory nuclei.
Collapse
Affiliation(s)
- Nichole L Beebe
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, 44272
| | - Brett R Schofield
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, 44272
| |
Collapse
|
4
|
Abstract
The superior olivary complex (SOC) is a collection of brainstem auditory nuclei which play essential roles in the localization of sound sources, temporal coding of vocalizations and descending modulation of the cochlea. Notwithstanding, the SOC nuclei vary considerably between species in accordance with the auditory needs of the animal. The canine SOC was subjected to anatomical and physiological examination nearly 50 years ago and was then virtually forgotten. Herein, we aimed to characterize the nuclei of the canine SOC using quantitative morphometrics, estimation of neuronal number, histochemistry for perineuronal nets and immunofluorescence for the calcium binding proteins calbindin and calretinin. We found the principal nuclei to be extremely well developed: the lateral superior olive (LSO) contained over 20,000 neurons and the medial superior olive (MSO) contained over 15,000 neurons. In nearly all non-chiropterian terrestrial mammals, the MSO exists as a thin, vertical column of neurons. The canine MSO was folded into a U-shaped contour and had associated with the ventromedial tip a small, round collection of neurons we termed the tail nucleus of the MSO. Further, we found evidence within the LSO, MSO and medial nucleus of the trapezoid body (MNTB) for significant morphological variations along the mediolateral or rostrocaudal axes. Finally, the majority of MNTB neurons were calbindin-immunopositive and associated with calretinin-immunopositive calyceal terminals. Together, these observations suggest the canine SOC complies with the basic plan of the mammalian SOC but possesses a number of unique anatomical features.
Collapse
Affiliation(s)
- Tatiana Fech
- Department of Anatomy, Lake Erie College of Osteopathic Medicine, Erie, PA, USA
| | | | - Randy J Kulesza
- Department of Anatomy, Lake Erie College of Osteopathic Medicine, Erie, PA, USA.
| |
Collapse
|
5
|
Bitanihirwe BKY, Mauney SA, Woo TUW. Weaving a Net of Neurobiological Mechanisms in Schizophrenia and Unraveling the Underlying Pathophysiology. Biol Psychiatry 2016; 80:589-98. [PMID: 27113498 PMCID: PMC5017894 DOI: 10.1016/j.biopsych.2016.03.1047] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 02/14/2016] [Accepted: 03/03/2016] [Indexed: 12/26/2022]
Abstract
Perineuronal nets (PNNs) are enigmatic structures composed of extracellular matrix molecules that encapsulate the soma, dendrites, and axon segments of neurons in a lattice-like fashion. Although most PNNs condense around parvalbumin-expressing gamma-aminobutyric acidergic interneurons, some glutamatergic pyramidal cells in the brain are also surrounded by PNNs. Experimental findings suggest pivotal roles of PNNs in the regulation of synaptic formation and function. Also, an increasing body of evidence links PNN abnormalities to schizophrenia. The number of PNNs progressively increases during postnatal development until plateauing around the period of late adolescence and early adulthood, which temporally coincides with the age of onset of schizophrenia. Given the established role of PNNs in modulating developmental plasticity, the PNN represents a possible candidate for altering the onset and progression of schizophrenia. Similarly, the reported function of PNNs in regulating the trafficking of glutamate receptors places them in a critical position to modulate synaptic pathology, considered a cardinal feature of schizophrenia. We discuss the physiologic role of PNNs in neural function, synaptic assembly, and plasticity as well as how they interface with circuit/system mechanisms of cognition. An integrated understanding of these neurobiological processes should provide a better basis to elucidate how PNN abnormalities influence brain function and contribute to the pathogenesis of neurodevelopmental disorders such as schizophrenia.
Collapse
Affiliation(s)
- Byron K Y Bitanihirwe
- Department of International Health, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland
| | - Sarah A Mauney
- Program in Cellular Neuropathology, McLean Hospital, Belmont
| | - Tsung-Ung W Woo
- Program in Cellular Neuropathology, McLean Hospital, Belmont; Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Department of Psychiatry, Harvard Medical School, Boston, Massachusetts.
| |
Collapse
|
6
|
Perineuronal nets in the auditory system. Hear Res 2015; 329:21-32. [DOI: 10.1016/j.heares.2014.12.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 12/03/2014] [Accepted: 12/29/2014] [Indexed: 12/19/2022]
|
7
|
Bitanihirwe BKY, Woo TUW. Perineuronal nets and schizophrenia: the importance of neuronal coatings. Neurosci Biobehav Rev 2014; 45:85-99. [PMID: 24709070 DOI: 10.1016/j.neubiorev.2014.03.018] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 02/19/2014] [Accepted: 03/25/2014] [Indexed: 12/17/2022]
Abstract
Schizophrenia is a complex brain disorder associated with deficits in synaptic connectivity. The insidious onset of this illness during late adolescence and early adulthood has been reported to be dependent on several key processes of brain development including synaptic refinement, myelination and the physiological maturation of inhibitory neural networks. Interestingly, these events coincide with the appearance of perineuronal nets (PNNs), reticular structures composed of components of the extracellular matrix that coat a variety of cells in the mammalian brain. Until recently, the functions of the PNN had remained enigmatic, but are now considered to be important in development of the central nervous system, neuronal protection and synaptic plasticity, all elements which have been associated with schizophrenia. Here, we review the emerging evidence linking PNNs to schizophrenia. Future studies aimed at further elucidating the functions of PNNs will provide new insights into the pathophysiology of schizophrenia leading to the identification of novel therapeutic targets with the potential to restore normal synaptic integrity in the brain of patients afflicted by this illness.
Collapse
Affiliation(s)
| | - Tsung-Ung W Woo
- Program in Cellular Neuropathology, McLean Hospital, Belmont, MA, USA; Department of Psychiatry, Harvard Medical School, Boston, MA, USA; Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, USA.
| |
Collapse
|
8
|
Foster NL, Mellott JG, Schofield BR. Perineuronal nets and GABAergic cells in the inferior colliculus of guinea pigs. Front Neuroanat 2014; 7:53. [PMID: 24409124 PMCID: PMC3884149 DOI: 10.3389/fnana.2013.00053] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 12/22/2013] [Indexed: 12/24/2022] Open
Abstract
Perineuronal nets (PNs) are aggregates of extracellular matrix that have been associated with neuronal plasticity, critical periods, fast-spiking cells and protection from oxidative stress. Although PNs have been reported in the auditory system in several species, there is disagreement about the distribution of PNs within the inferior colliculus (IC), an important auditory hub in the midbrain. Furthermore, PNs in many brain areas are preferentially associated with GABAergic cells, but whether such an association exists in the IC has not been addressed. We used Wisteria floribunda agglutinin staining and immunohistochemistry in guinea pigs to examine PNs within the IC. PNs are present in all IC subdivisions and are densest in the central portions of the IC. Throughout the IC, PNs are preferentially associated with GABAergic cells. Not all GABAergic cells are surrounded by PNs, so the presence of PNs can be used to subdivide IC GABAergic cells into “netted” and “non-netted” categories. Finally, PNs in the IC, like those in other brain areas, display molecular heterogeneity that suggests a multitude of functions.
Collapse
Affiliation(s)
- Nichole L Foster
- School of Biomedical Sciences, Kent State University Kent, OH, USA ; Department of Anatomy and Neurobiology, College of Medicine, Northeast Ohio Medical University Rootstown, OH, USA
| | - Jeffrey G Mellott
- Department of Anatomy and Neurobiology, College of Medicine, Northeast Ohio Medical University Rootstown, OH, USA
| | - Brett R Schofield
- School of Biomedical Sciences, Kent State University Kent, OH, USA ; Department of Anatomy and Neurobiology, College of Medicine, Northeast Ohio Medical University Rootstown, OH, USA
| |
Collapse
|
9
|
|
10
|
Myers AK, Ray J, Kulesza RJ. Neonatal conductive hearing loss disrupts the development of the Cat-315 epitope on perineuronal nets in the rat superior olivary complex. Brain Res 2012; 1465:34-47. [DOI: 10.1016/j.brainres.2012.05.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 05/08/2012] [Accepted: 05/13/2012] [Indexed: 01/22/2023]
|
11
|
Schmidt E, Wolski TP, Kulesza RJ. Distribution of perineuronal nets in the human superior olivary complex. Hear Res 2010; 265:15-24. [PMID: 20307636 DOI: 10.1016/j.heares.2010.03.077] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 03/17/2010] [Accepted: 03/17/2010] [Indexed: 10/19/2022]
Abstract
Perineuronal nets (PNNs) are specialized assemblies of chondroitin sulfate proteoglycans (CSPGs) in the central nervous system that form a lattice-like covering over the cell body, primary dendrites and initial axon segment of select neuronal populations. PNNs appear to play significant roles in development of the central nervous system, neuronal protection, synaptic plasticity and local ion homeostasis. In seven human brainstems (average age=81 years), we have utilized Wisteria floribunda (WFA) histochemistry and immunocytochemistry for CSPG to map the distribution of PNNs within the nuclei of the human superior olivary complex (SOC). Within the SOC, the majority of net-bearing neurons are situated in the most medially situated nuclei, especially the superior paraolivary nucleus and medial nucleus of the trapezoid body. Net-bearing neurons are consistently found in the ventral nucleus of the trapezoid body and posterior periolivary nucleus, but to a lesser extent in the lateral nucleus of the trapezoid body. Finally, perineuronal nets are typically absent from the lateral and medial superior olives.
Collapse
Affiliation(s)
- Elise Schmidt
- Auditory Research Center, Lake Erie College of Osteopathic Medicine, Erie, PA 16509, USA
| | | | | |
Collapse
|
12
|
Hilbig H, Nowack S, Boeckler K, Bidmon HJ, Zilles K. Characterization of neuronal subsets surrounded by perineuronal nets in the rhesus auditory brainstem. J Anat 2007; 210:507-17. [PMID: 17451528 PMCID: PMC2375744 DOI: 10.1111/j.1469-7580.2007.00713.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The distribution of perineuronal nets and the potassium channel subunit Kv3.1b was studied in the subdivisions of the cochlear nucleus, the medial nucleus of the trapezoid body, the medial and lateral superior olivary nuclei, the lateral lemniscal nucleus and the inferior colliculus of the rhesus monkey. Additional sections were used for receptor autoradiography to visualize the patterns of GABAA and GABAB receptor distribution. The Kv3.1b protein and perineuronal nets [visualized as Wisteria floribunda agglutinin (WFA) binding] were revealed, showing corresponding region-specific patterns of distribution. There was a gradient of labelled perineuronal nets which corresponded to that seen for the intensity of Kv3.1b expression. In the cochlear nucleus intensely and faintly stained perineuronal nets were intermingled, whereas in the medial nucleus of the trapezoid body the pattern changed to intensely stained perineuronal nets in the medial part and weakly labelled nets in its lateral part. In the inferior colliculus, intensely labelled perineuronal nets were arranged in clusters and faintly labelled nets were arranged in sheets. Using receptor autoradiography, GABAB receptor expression in the anterior ventral cochlear nucleus was revealed. The medial part of the medial nucleus of the trapezoid body showed a high number of GABAA binding sites whereas the lateral part exhibited more binding sites for GABAB. In the inferior colliculus, we found moderate GABAB receptor expression. In conclusion, intensely WFA-labelled structures are those known to be functionally involved in high-frequency processing.
Collapse
|
13
|
Rauch U, Kappler J. Chondroitin/Dermatan Sulfates in the Central Nervous System: Their Structures and Functions in Health and Disease. CHONDROITIN SULFATE: STRUCTURE, ROLE AND PHARMACOLOGICAL ACTIVITY 2006; 53:337-56. [PMID: 17239774 DOI: 10.1016/s1054-3589(05)53016-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Uwe Rauch
- Department of Experimental Pathology, Universitet Lund, Lund, Sweden
| | | |
Collapse
|
14
|
Abstract
We produced a monoclonal antibody, named A20, which specifically recognizes a 35 kDa protein and stains myelinated axons in zebrafish brain. The A20 antigen is located at the outside of the myelin layer of large axons, and comprises a fine meshwork composed of thin unit fibers about 1-2 microm in length and about 100-200 nm in thickness. The unit fibers form pentagonal and hexagonal structures, which further polymerize into an envelope structure on the axons. The A20 monoclonal antibody did not stain neuronal cell bodies nor synapses. Instead, the distribution of the A20 antigen was along axons, practically coincident with the distribution of myelin basic protein. The monoclonal antibody stained only axons in the central nervous system (CNS), and not the extracellular matrix surrounding Schwann cells. These results suggest that this antigenic meshwork (which we call the periaxonal net) is synthesized by oligodendrocytes. During the development of the zebrafish brain, the periaxonal net appeared after the formation of myelin on the axons. The periaxonal net developed first at the brain stem, then gradually appeared at the caudal end of the spinal cord. The thickness of the periaxonal net around the Mauthner axon changed during development. Although the thickness of the Mauthner axon continues to grow throughout life, the thickness of periaxonal net stopped growing at 6 months after fertilization.
Collapse
Affiliation(s)
- Noriko Arata
- Department of Biology, Faculty of Science, Okayama University, Japan
| | | |
Collapse
|
15
|
Härtig W, Singer A, Grosche J, Brauer K, Ottersen OP, Brückner G. Perineuronal nets in the rat medial nucleus of the trapezoid body surround neurons immunoreactive for various amino acids, calcium-binding proteins and the potassium channel subunit Kv3.1b. Brain Res 2001; 899:123-33. [PMID: 11311873 DOI: 10.1016/s0006-8993(01)02211-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Perineuronal nets (PNs) are known as chondroitin sulfate-rich, lattice-like coatings of the extracellular matrix ensheathing mainly GABAergic, parvalbumin-containing neurons especially in the cerebral cortex. PNs have also been detected around GABA-immunonegative cells which were shown to be not aminergic, cholinergic, nitrinergic or peptidergic in various brain regions of some mammalian species. To find out whether glycine and aspartate may occur in net-bearing neurons the present study was focused on the rat medial nucleus of the trapezoid body (MNTB) which contains a large portion of cells immunoreactive for these amino acids, but appears to be devoid of GABA-immunoreactive cell bodies. PNs were detected around many glycine- and aspartate-immunopositive neurons in the MNTB by carbocyanine double labeling and confocal laser scanning microscopy. An additional finding was that the lectin-cytochemically stained extracellular matrix surrounds the calretinin-immunoreactive calyces of Held known as giant glutamatergic endbulbs which cover glycinergic principal cells in the MNTB. As elucidated by triple fluorescence labeling, the vast majority of somata co-expressed the calcium-binding proteins parvalbumin and calbindin, but not calretinin. The observed co-localization of PNs and immunoreactivity for the voltage-dependent potassium channel Kv3.1b - as an established marker of fast-firing parvalbumin-containing neurons - supports the assumed function of PNs as a cation exchanger ensuring rapid ion transport as required by highly active nerve cells.
Collapse
Affiliation(s)
- W Härtig
- University of Leipzig, Paul Flechsig Institute for Brain Research, Jahnallee 59, D-04109, Leipzig, Germany
| | | | | | | | | | | |
Collapse
|
16
|
Abstract
Golgi ranked the peripheral reticulum--which adheres intimately to nerve cell surfaces--alongside the intracellular reticulum, or Golgi apparatus,which immortalized his name. At first dismissed as an artefact of capricious staining techniques, this peripheral reticulum, or perineuronal net, is now recognized as a genuine entity in neurocytology. It represents a complex of extracellular matrix molecules interposed between the meshwork of glial processes, from which they are indistinguishable, and nerve-cell surfaces. In no other branch of neuroscience has the waxing and waning of interest in any morphological entity been so pronounced as in the case of the perineuronal net. This review traces the history of this enigmatic structure from its conception to the present time, brings to light the keen observational powers of morphologists at the turn of the century and reveals how their sagacious forethought anticipated current thinking on the role of perineuronal nets.
Collapse
Affiliation(s)
- M R Celio
- Institute of Histology and General Embryology, and Programme in Neurosciences, University of Fribourg, Switzerland
| | | | | | | |
Collapse
|