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Kobayashi M, Nakaya Y, Kobayashi S. Functional roles of descending projections from the cerebral cortex to the trigeminal spinal nucleus caudalis in orofacial nociceptive information processing. J Oral Biosci 2024:S1349-0079(24)00087-2. [PMID: 38734177 DOI: 10.1016/j.job.2024.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Revised: 05/08/2024] [Accepted: 05/08/2024] [Indexed: 05/13/2024]
Abstract
BACKGROUND The trigeminal spinal subnucleus caudalis (Sp5C), also known as the medullary dorsal horn, receives orofacial somatosensory inputs, particularly nociceptive inputs, from the trigeminal nerve. In the Sp5C, excitatory and inhibitory neurons, glutamatergic and GABAergic/glycinergic neurons, respectively, form the local circuits. The axons of the glutamatergic neurons in lamina I ascend toward the thalamic and parabrachial nuclei, and this projection is the main pathway of orofacial nociception. Additionally, the axons of the higher brain regions, including the locus coeruleus, dorsal raphe, and cerebral cortex, are sent to the Sp5C. HIGHLIGHT Among these descending projections, this review focuses on the functional profiles of the corticotrigeminal projections to the Sp5C, along with their anatomical aspects. The primary and secondary somatosensory and insular cortices are of particular interest. CONCLUSION Corticotrigeminal projections from the somatosensory cortex to the Sp5C play a suppressive role in nociceptive information processing, whereas recent studies have demonstrated a facilitative role of the insular cortex in nociceptive information processing at the Sp5C level.
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Affiliation(s)
- Masayuki Kobayashi
- Department of Pharmacology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; Division of Oral and Craniomaxillofacial Research, Dental Research Center, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
| | - Yuka Nakaya
- Department of Pharmacology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; Division of Oral and Craniomaxillofacial Research, Dental Research Center, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
| | - Satomi Kobayashi
- Department of Pharmacology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; Department of Biology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
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Olfactory stimulation Inhibits Nociceptive Signal Processing at the Input Stage of the Central Trigeminal System. Neuroscience 2021; 479:35-47. [PMID: 34695536 DOI: 10.1016/j.neuroscience.2021.10.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/08/2021] [Accepted: 10/15/2021] [Indexed: 01/06/2023]
Abstract
The spinal trigeminal nucleus caudalis (SpVc) in the mammalian brainstem serves a pivotal function in pain processing. As the main relay center for nociceptive signals, SpVc conducts pain-related signals from various regions of the head toward higher levels of central processing such as the thalamus. SpVc also receives modulatory signals from other brain areas, which can alleviate the perception of headache. We studied the impact of olfactory co-stimulation on pain-related behavior and SpVc neural activity in mice. Using the TRPA1 agonist allyl isothiocyanate (AITC) as noxious stimulus, we quantified the aversive response and the perceived pain intensity by evaluating explorative running and the mouse grimace scale, respectively. We found that the floral odorants phenylethyl alcohol (PEA) and lavender oil mitigated the aversive response to AITC. Consistent with this finding, a newly developed, automated quantification of c-Fos expression in SpVc revealed that co-stimulation with PEA or lavender profoundly reduced network activity in the presence of AITC. These results demonstrated a substantial analgesic potential of odor stimulation in the trigeminal system and provide an explanation for the palliative effect of odors in the treatment of headache.
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Staiger JF, Petersen CCH. Neuronal Circuits in Barrel Cortex for Whisker Sensory Perception. Physiol Rev 2020; 101:353-415. [PMID: 32816652 DOI: 10.1152/physrev.00019.2019] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The array of whiskers on the snout provides rodents with tactile sensory information relating to the size, shape and texture of objects in their immediate environment. Rodents can use their whiskers to detect stimuli, distinguish textures, locate objects and navigate. Important aspects of whisker sensation are thought to result from neuronal computations in the whisker somatosensory cortex (wS1). Each whisker is individually represented in the somatotopic map of wS1 by an anatomical unit named a 'barrel' (hence also called barrel cortex). This allows precise investigation of sensory processing in the context of a well-defined map. Here, we first review the signaling pathways from the whiskers to wS1, and then discuss current understanding of the various types of excitatory and inhibitory neurons present within wS1. Different classes of cells can be defined according to anatomical, electrophysiological and molecular features. The synaptic connectivity of neurons within local wS1 microcircuits, as well as their long-range interactions and the impact of neuromodulators, are beginning to be understood. Recent technological progress has allowed cell-type-specific connectivity to be related to cell-type-specific activity during whisker-related behaviors. An important goal for future research is to obtain a causal and mechanistic understanding of how selected aspects of tactile sensory information are processed by specific types of neurons in the synaptically connected neuronal networks of wS1 and signaled to downstream brain areas, thus contributing to sensory-guided decision-making.
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Affiliation(s)
- Jochen F Staiger
- University Medical Center Göttingen, Institute for Neuroanatomy, Göttingen, Germany; and Laboratory of Sensory Processing, Faculty of Life Sciences, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Carl C H Petersen
- University Medical Center Göttingen, Institute for Neuroanatomy, Göttingen, Germany; and Laboratory of Sensory Processing, Faculty of Life Sciences, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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Cortical Regulation of Nociception of the Trigeminal Nucleus Caudalis. J Neurosci 2017; 37:11431-11440. [PMID: 29066554 DOI: 10.1523/jneurosci.3897-16.2017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 10/01/2017] [Accepted: 10/11/2017] [Indexed: 12/23/2022] Open
Abstract
Pain perception is strongly influenced by descending pathways from "higher" brain centers that regulate the activity of spinal circuits. In addition to the extensively studied descending system originating from the medulla, the neocortex provides dense anatomical projections that directly target neurons in the spinal cord and the spinal trigeminal nucleus caudalis (SpVc). Evidence exists that these corticotrigeminal pathways may modulate the processing of nociceptive inputs by SpVc, and regulate pain perception. We demonstrate here, with anatomical and optogenetic methods, and using both rats and mice (of both sexes), that corticotrigeminal axons densely innervate SpVc, where they target and directly activate inhibitory and excitatory neurons. Electrophysiological recordings reveal that stimulation of primary somatosensory cortex potently suppresses SpVc responses to noxious stimuli and produces behavioral hypoalgesia. These findings demonstrate that the corticotrigeminal pathway is a potent modulator of nociception and a potential target for interventions to alleviate chronic pain.SIGNIFICANCE STATEMENT Many chronic pain conditions are resistant to conventional therapy. Promising new approaches to pain management capitalize on the brain's own mechanisms for controlling pain perception. Here we demonstrate that cortical neurons directly innervate the brainstem to drive feedforward inhibition of nociceptive neurons. This corticotrigeminal pathway suppresses the activity of these neurons and produces analgesia. This corticotrigeminal pathway may constitute a therapeutic target for chronic pain.
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Chang CH. Lateral Orbitofrontal Cortical Modulation on the Medial Prefrontal Cortex-Amygdala Pathway: Differential Regulation of Intra-Amygdala GABAA and GABAB Receptors. Int J Neuropsychopharmacol 2017; 20:602-610. [PMID: 28444246 PMCID: PMC5492808 DOI: 10.1093/ijnp/pyx027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 04/18/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The basolateral complex of the amygdala receives inputs from neocortical areas, including the medial prefrontal cortex and lateral orbitofrontal cortex. Earlier studies have shown that lateral orbitofrontal cortex activation exerts an inhibitory gating on medial prefrontal cortex-amygdala information flow. Here we examined the individual role of GABAA and GABAB receptors in this process. METHODS In vivo extracellular single-unit recordings were done in anesthetized rats. We searched amygdala neurons that fire in response to medial prefrontal cortex activation, tested lateral orbitofrontal cortex gating at different delays (lateral orbitofrontal cortex-medial prefrontal cortex delays: 25, 50, 100, 250, 500, and 1000 milliseconds), and examined differential contribution of GABAA and GABAB receptors with iontophoresis. RESULTS Relative to baseline, lateral orbitofrontal cortex stimulation exerted an inhibitory modulatory gating on the medial prefrontal cortex-amygdala pathway and was effective up to a long delay of 500 ms (long-delay latencies at 100, 250, and 500 milliseconds). Moreover, blockade of intra-amygdala GABAA receptors with bicuculline abolished the lateral orbitofrontal cortex inhibitory gating at both short- (25 milliseconds) and long-delay (100 milliseconds) intervals, while blockade of GABAB receptors with saclofen reversed the inhibitory gating at long delay (100 milliseconds) only. Among the majority of the neurons examined (8 of 9), inactivation of either GABAA or GABAB receptors during baseline did not change evoked probability per se, suggesting that local feed-forward inhibitory mechanism is pathway specific. CONCLUSIONS Our results suggest that the effect of lateral orbitofrontal cortex inhibitory modulatory gating was effective up to 500 milliseconds and that intra-amygdala GABAA and GABAB receptors differentially modulate the short- and long-delay lateral orbitofrontal cortex inhibitory gating on the medial prefrontal cortex-amygdala pathway.
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Affiliation(s)
- Chun-hui Chang
- Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu, Taiwan
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Opioid subtype- and cell-type-dependent regulation of inhibitory synaptic transmission in the rat insular cortex. Neuroscience 2016; 339:478-490. [DOI: 10.1016/j.neuroscience.2016.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/13/2016] [Accepted: 10/02/2016] [Indexed: 12/22/2022]
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Yokota E, Koyanagi Y, Nakamura H, Horinuki E, Oi Y, Kobayashi M. Opposite effects of mu and delta opioid receptor agonists on excitatory propagation induced in rat somatosensory and insular cortices by dental pulp stimulation. Neurosci Lett 2016; 628:52-8. [DOI: 10.1016/j.neulet.2016.05.065] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 05/20/2016] [Accepted: 05/27/2016] [Indexed: 11/27/2022]
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Dieb W, Ouachikh O, Alves S, Boucher Y, Durif F, Hafidi A. Nigrostriatal dopaminergic depletion increases static orofacial allodynia. J Headache Pain 2016; 17:11. [PMID: 26885825 PMCID: PMC4757596 DOI: 10.1186/s10194-016-0607-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 02/12/2016] [Indexed: 01/05/2023] Open
Abstract
Background This study investigated mesencephalic dopamine depletion effects on static mechanical allodynia (SMA) elicited by chronic constriction of the infraorbitary nerve (CCI-IoN). Methods Dopamine depletion (6-OHDA administration into the medial forebrain bundle) effects on CCI-IoN-induced SMA were explored using behavioral (nocifensive behavior score upon non-noxious stimuli using von Frey filament), pharmacological (bromocriptine injections) and immunohistochemical (PKCγ and pERK1/2) techniques. Results The central dopamine depletion increased significantly the SMA score. Intraperitoneal and intracisternal injections of bromocriptine alleviated the allodynic behavior observed in both CCI-IoN and CCI-IoN + 6-OHDA animal groups. At the cellular level, dopamine depletion induced a significant increase in PKCγ expression in the medullary dorsal horn (MDH) in rat with CCI-IoN + 6-OHDA when compared to sham animals (CCI-IoN only). Similarly, after static non-noxious stimuli, the expression of pain marker proteins pERK1/2 within the MDH revealed significantly a higher number of positive cells in CCI-IoN + 6-OHDA rats when compared to the CCI-IoN group. Conclusion This study demonstrates that nigrostriatal dopamine depletion exacerbates the neuropathic pain resulting from CCI-IoN. This effect is probably due to an action through descending pain inhibitory systems which increased pain sensitization at the MDH level. It demonstrates also an analgesic effect elicited by D2R activation at the segmental level. Electronic supplementary material The online version of this article (doi:10.1186/s10194-016-0607-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wisam Dieb
- UFR Odontologie, Université Paris Diderot, Paris, France. .,Centre de Psychiatrie et Neurosciences, INSERM U894, Paris, France. .,Clermont Université, Université d'Auvergne, EA7280, Clermont-Ferrand, France.
| | - Omar Ouachikh
- Clermont Université, Université d'Auvergne, EA7280, Clermont-Ferrand, France.
| | - Sofia Alves
- Clermont Université, Université d'Auvergne, EA7280, Clermont-Ferrand, France.
| | - Yves Boucher
- UFR Odontologie, Université Paris Diderot, Paris, France. .,Centre de Psychiatrie et Neurosciences, INSERM U894, Paris, France.
| | - Franck Durif
- Clermont Université, Université d'Auvergne, EA7280, Clermont-Ferrand, France. .,CHU Clermont-Ferrand, Service de Neurologie, 63000, Clermont-Ferrand, France.
| | - Aziz Hafidi
- Clermont Université, Université d'Auvergne, EA7280, Clermont-Ferrand, France.
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Nakamura H, Shirakawa T, Koshikawa N, Kobayashi M. Distinct Excitation to Pulpal Stimuli between Somatosensory and Insular Cortices. J Dent Res 2015; 95:180-7. [DOI: 10.1177/0022034515611047] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Somatosensory information from the dental pulp is processed in the primary (S1) and secondary somatosensory cortex (S2) and in the insular oral region (IOR). Stimulation of maxillary incisor and molar initially induces excitation in S2/IOR, rostrodorsal to the mandibular incisor and molar pulp-responding regions. Although S1 and S2/IOR play their own roles in nociceptive information processing, the anatomical and physiological differences in the temporal activation kinetics, dependency on stimulation intensity, and additive or summative effects of simultaneous pulpal stimulation are still unknown. This information contributes not only to understanding topographical organization but also to speculating about the roles of S1 and S2/IOR in clinical aspects of pain regulation. In vivo optical imaging enables investigation of the spatiotemporal profiles of cortical excitation with high resolution. We determined the distinct features of optical responses to nociceptive stimulation of dental pulps between S1 and S2/IOR. In comparison to S1, optical signals in S2/IOR showed a larger amplitude with a shorter rise time and a longer decay time responding to maxillary molar pulp stimulation. The latency of excitation in S2/IOR was shorter than in S1. S2/IOR exhibited a lower threshold to evoke optical responses than S1, and the peak amplitude was larger in S2/IOR than in S1. Unexpectedly, the topography of S1 that responded to maxillary and mandibular incisor and molar pulps overlapped with the most ventral sites in S1 that was densely stained with cytochrome oxidase. An additive effect was observed in both S1 and S2/IOR after simultaneous stimulation of bilateral maxillary molar pulps but not after contralateral maxillary and mandibular molar pulp stimulation. These findings suggest that S2/IOR is more sensitive for detecting dental pulp sensation and codes stimulation intensity more precisely than S1. In addition, contra- and ipsilateral dental pulp nociception converges onto spatially closed sites in S1 and S2/IOR.
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Affiliation(s)
- H. Nakamura
- Department of Pharmacology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
- Department of Pediatric Dentistry, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | - T. Shirakawa
- Department of Pediatric Dentistry, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
- Division of Oral and Craniomaxillofacial Research, Dental Research Center, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | - N. Koshikawa
- Department of Pharmacology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
- Division of Oral and Craniomaxillofacial Research, Dental Research Center, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | - M. Kobayashi
- Department of Pharmacology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
- Division of Oral and Craniomaxillofacial Research, Dental Research Center, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
- Molecular Imaging Research Center, RIKEN, Chuo-ku, Kobe, Japan
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Smith JB, Watson GDR, Alloway KD, Schwarz C, Chakrabarti S. Corticofugal projection patterns of whisker sensorimotor cortex to the sensory trigeminal nuclei. Front Neural Circuits 2015; 9:53. [PMID: 26483640 PMCID: PMC4588702 DOI: 10.3389/fncir.2015.00053] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 09/14/2015] [Indexed: 11/29/2022] Open
Abstract
The primary (S1) and secondary (S2) somatosensory cortices project to several trigeminal sensory nuclei. One putative function of these corticofugal projections is the gating of sensory transmission through the trigeminal principal nucleus (Pr5), and some have proposed that S1 and S2 project differentially to the spinal trigeminal subnuclei, which have inhibitory circuits that could inhibit or disinhibit the output projections of Pr5. Very little, however, is known about the origin of sensorimotor corticofugal projections and their patterns of termination in the various trigeminal nuclei. We addressed this issue by injecting anterograde tracers in S1, S2 and primary motor (M1) cortices, and quantitatively characterizing the distribution of labeled terminals within the entire rostro-caudal chain of trigeminal sub-nuclei. We confirmed our anterograde tracing results by injecting retrograde tracers at various rostro-caudal levels within the trigeminal sensory nuclei to determine the position of retrogradely labeled cortical cells with respect to S1 barrel cortex. Our results demonstrate that S1 and S2 projections terminate in largely overlapping regions but show some significant differences. Whereas S1 projection terminals tend to cluster within the principal trigeminal (Pr5), caudal spinal trigeminal interpolaris (Sp5ic), and the dorsal spinal trigeminal caudalis (Sp5c), S2 projection terminals are distributed in a continuum across all trigeminal nuclei. Contrary to the view that sensory gating could be mediated by differential activation of inhibitory interconnections between the spinal trigeminal subnuclei, we observed that projections from S1 and S2 are largely overlapping in these subnuclei despite the differences noted earlier.
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Affiliation(s)
- Jared B Smith
- Department of Engineering Science and Mechanics, Pennsylvania State University University Park, PA, USA ; Center for Neural Engineering, Huck Institute of Life Sciences, Pennsylvania State University University Park, PA, USA
| | - Glenn D R Watson
- Center for Neural Engineering, Huck Institute of Life Sciences, Pennsylvania State University University Park, PA, USA ; Department of Neural and Behavioral Sciences, Pennsylvania State University College of Medicine Hershey, PA, USA
| | - Kevin D Alloway
- Center for Neural Engineering, Huck Institute of Life Sciences, Pennsylvania State University University Park, PA, USA ; Department of Neural and Behavioral Sciences, Pennsylvania State University College of Medicine Hershey, PA, USA
| | - Cornelius Schwarz
- Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, Eberhard Karls University of Tübingen Tübingen, Germany ; Systems Neurophysiology, Werner Reichardt Center for Integrative Neurosciences, Eberhard Karls University of Tübingen Tübingen, Germany
| | - Shubhodeep Chakrabarti
- Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, Eberhard Karls University of Tübingen Tübingen, Germany ; Systems Neurophysiology, Werner Reichardt Center for Integrative Neurosciences, Eberhard Karls University of Tübingen Tübingen, Germany
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Martin YB, Negredo P, Villacorta-Atienza JA, Avendaño C. Trigeminal intersubnuclear neurons: morphometry and input-dependent structural plasticity in adult rats. J Comp Neurol 2014; 522:1597-617. [PMID: 24178892 DOI: 10.1002/cne.23494] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 10/11/2013] [Accepted: 10/15/2013] [Indexed: 11/09/2022]
Abstract
Intersubnuclear neurons in the caudal division of the spinal trigeminal nucleus that project to the principal nucleus (Pr5) play an active role in shaping the receptive fields of other neurons, at different levels in the ascending sensory system that processes information originating from the vibrissae. By using retrograde labeling and digital reconstruction, we investigated the morphometry and topology of the dendritic trees of these neurons and the changes induced by long-term experience-dependent plasticity in adult male rats. Primary afferent input was either eliminated by transection of the right infraorbital nerve (IoN), or selectively altered by repeated whisker clipping on the right side. These neurons do not display asymmetries between sides in basic metric and topologic parameters (global number of trees, nodes, spines, or dendritic ends), although neurons on the left tend to have longer terminal segments. Ipsilaterally, both deafferentation (IoN transection) and deprivation (whisker trimming) reduced the density of spines, and the former also caused a global increase in total dendritic length and a relative increase in more complex arbors. Contralaterally, deafferentation reduced more complex dendritic trees, and caused a moderate decline in dendritic length and spatial reach, and a loss of spines in number and density. Deprivation caused a similar, but more profound, effect on spines. Our findings provide original quantitative descriptions of a scarcely known cell population, and show that denervation- or deprivation-derived plasticity is expressed not only by neurons at higher levels of the sensory pathways, but also by neurons in key subcortical circuits for sensory processing.
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Affiliation(s)
- Yasmina B Martin
- Department of Anatomy, Histology, & Neuroscience, Autonoma University of Madrid, 28029, Madrid, Spain; Department of Anatomy, Francisco de Vitoria University, 28223, Pozuelo de Alarcón, Madrid, Spain
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Sokolov AY, Lyubashina OA, Amelin AV, Panteleev SS. The role of gamma-aminobutyric acid in migraine pathogenesis. NEUROCHEM J+ 2014. [DOI: 10.1134/s1819712414020093] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Malmierca E, Chaves-Coira I, Rodrigo-Angulo M, Nuñez A. Corticofugal projections induce long-lasting effects on somatosensory responses in the trigeminal complex of the rat. Front Syst Neurosci 2014; 8:100. [PMID: 24904321 PMCID: PMC4033105 DOI: 10.3389/fnsys.2014.00100] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 05/08/2014] [Indexed: 11/17/2022] Open
Abstract
The sensory information flow at subcortical relay stations is controlled by the action of topographic connections from the neocortex. To determinate the functional properties of the somatosensory corticofugal projections to the principal (Pr5) and caudal spinal (Sp5C) trigeminal nuclei, we performed unitary recordings in anesthetized rats. To examine the effect of these cortical projections we used tactile stimulation of the whisker and electrical stimulation of somatosensory cortices. Corticofugal anatomical projections to Pr5 and Sp5C nuclei were detected by using retrograde fluorescent tracers. Neurons projecting exclusively to Pr5 were located in the cingulate cortex while neurons projecting to both Sp5C and Pr5 nuclei were located in the somatosensory and insular cortices (>75% of neurons). Physiological results indicated that primary somatosensory cortex produced a short-lasting facilitating or inhibiting effects (<5 min) of tactile responses in Pr5 nucleus through activation of NMDA glutamatergic or GABAA receptors since effects were blocked by iontophoretically application of APV and bicuculline, respectively. In contrast, stimulation of secondary somatosensory cortex did not affect most of the Pr5 neurons; however both cortices inhibited the nociceptive responses in the Sp5C nucleus through activation of glycinergic or GABAA receptors because effects were blocked by iontophoretically application of strychnine and bicuculline, respectively. These and anatomical results demonstrated that the somatosensory cortices projects to Pr5 nucleus to modulate tactile responses by excitatory and inhibitory actions, while projections to the Sp5C nucleus control nociceptive sensory transmission by only inhibitory effects. Thus, somatosensory cortices may modulate innocuous and noxious inputs simultaneously, contributing to the perception of specifically tactile or painful sensations.
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Affiliation(s)
- Eduardo Malmierca
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid Madrid, Spain
| | - Irene Chaves-Coira
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid Madrid, Spain
| | - Margarita Rodrigo-Angulo
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid Madrid, Spain
| | - Angel Nuñez
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid Madrid, Spain
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