Journal of Comparative Neurology最新文献

{"title":"The Molecular Architecture of Somatic Spines of the Lateral Septum","authors":"Daniela Hacker,&nbsp;Erich Weisheim,&nbsp;Michaela Schweizer,&nbsp;Undine Schneeweiß,&nbsp;Maximilian Borgmeyer,&nbsp;Michael Brecht,&nbsp;Marina Mikhaylova","doi":"10.1002/cne.70195","DOIUrl":"10.1002/cne.70195","url":null,"abstract":"<p>The lateral septum is a key subcortical structure and has been implicated in social memory. One aspect of social memory, the ability to recognize relatives, is conserved across vertebrate species and reflected in stable, lifelong memories. Synapses are considered to be the smallest unit of memory storage. Excitatory synapses are typically found on dendritic spines, whereas inhibitory synapses are mostly located on the dendritic shaft. Here, we investigate the synaptic architecture of unusual somatic spines, an apparent synaptic specialization of septal GABAergic neurons. We uncover the formation and molecular organization of septal somatic spines found in the lateral septum in in vivo and in vitro model systems using various microscopy approaches. We use classical label-free methods such as transmission electron microscopy and Golgi stainings and established new culturing methods for dissociated and organotypic septal slices that were kept in culture over multiple weeks. We describe the presence, morphology, ultrastructure, and molecular composition of excitatory somatic spines across multiple developmental stages in various model systems. We propose that the ability to develop such spines is an intrinsic feature of somatospiny neurons that does not depend on extra-septal connectivity. While smaller than dendritic spines, somatic spines exhibited distinct features, frequently containing secretory organelles such as autophagosomes, multivesicular bodies, and endosomes, but often lacking a spine apparatus and ribosomes. Our findings offer insights into the molecular architecture of septal somatic spines and establish a basis for further investigations into the somatic spines of the lateral septum.</p>","PeriodicalId":15552,"journal":{"name":"Journal of Comparative Neurology","volume":"534 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cne.70195","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148850839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anatomical Investigation Reveals a Second Olfactory System in Locusts","authors":"Zane N. Aldworth,&nbsp;Brian Kim,&nbsp;Kui Sun,&nbsp;Esther Ndungu,&nbsp;Vi Nguyen,&nbsp;Mark A. Stopfer","doi":"10.1002/cne.70197","DOIUrl":"https://doi.org/10.1002/cne.70197","url":null,"abstract":"<p>Olfaction in locusts offers a useful model for understanding how the brain encodes environmental information. While previous studies of olfaction in locusts have focused mainly on the antennal pathway, most insects, including locusts, possess olfactory receptors on their palps. Although they are traditionally considered to be gustatory or mechanosensory structures, accumulating molecular, electrophysiological, and behavioral evidence shows locust palps also mediate olfactory processing. The palps therefore initiate a second olfactory pathway, whose neural architecture and sensory functions remain largely unexplored. Here, we used anatomical approaches to characterize the chemosensory system of the palps in <i>Schistocerca americana</i>, mapping pathways from the peripheral sensilla through the brain to third-order neurons. We found that sensory input from the palps projects to two distinct regions: the gnathal ganglion, which integrates gustatory input from multiple head appendages, and the glomerular lobe of the cerebral ganglion, which, traditionally thought of as a gustatory center, appears instead to receive only olfactory input. The glomerular lobe, in turn, provides olfactory input to the accessory calyx of the mushroom body, a region traditionally considered gustatory. Notably, the palp and antennal olfactory pathways remain anatomically segregated through at least the third-order neurons. Our systematic characterization of the palp olfactory system anatomy challenges existing views of olfactory and gustatory integration in hemimetabolous insects and establishes a framework for comparative studies of antennal and palp-based olfactory coding.</p>","PeriodicalId":15552,"journal":{"name":"Journal of Comparative Neurology","volume":"534 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cne.70197","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148784612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of the Spinal Cord of the Annual Fish Garcialebias charrua: Morphology, Cell Proliferation, and NADPH-Diaphorase Activity","authors":"Stephanie Silva-Jaureguiberry,&nbsp;Laura Herrera-Astoga,&nbsp;Inés Berrosteguieta,&nbsp;Juan Carlos Rosillo,&nbsp;Anabel Sonia Fernández","doi":"10.1002/cne.70196","DOIUrl":"https://doi.org/10.1002/cne.70196","url":null,"abstract":"<div>\u0000 \u0000 <p>The spinal cord plays a central role in sensorimotor integration and exhibits substantial diversity across vertebrates in relation to ecological and behavioral demands. In teleost fish, however, detailed morphological and cellular analyses of the adult spinal cord remain scarce. Here, we provide the first comprehensive characterization of the adult spinal cord of the annual fish <i>Garcialebias charrua</i>, a species displaying pronounced environmental adaptation and sexual dimorphism. Using adult males and females, the spinal cord was systematically partitioned into five equally sized rostrocaudal regions (SI–SV) to evaluate regional variation in morphology, neurochemical organization, and cell proliferation. We analyzed gross morphology and cross-sectional features, the distribution and morphology of NADPH-diaphorase–positive (NADP-d⁺) neurons as indicators of nitric oxide–related signaling, and proliferative activity using 5-bromo-2′-deoxyuridine (BrdU) and 5-ethynyl-2′-deoxyuridine (EdU) incorporation. Our results reveal marked rostrocaudal heterogeneity in spinal cord morphometry, with dimorphic variation in the segment SIII associated with the dorsal fin, region-specific patterns of NADPH-d⁺ neuronal populations, and sustained cell proliferation throughout the entire spinal cord in both gray and white matter. Focused analysis of segment SIII, which exhibits distinctive anatomical features, demonstrated higher proliferative activity in the central canal and dorsal regions compared to ventral areas in both sexes, with males showing significantly increased proliferation across all analyzed regions. Finally, the combination of BrdU labeling with a neuronal lineage marker provides the first evidence of adult spinal cord neurogenesis in <i>G. charrua</i>. These findings highlight the spinal cord as a dynamic and sexually dimorphic substrate underlying neuroplasticity in annual fishes.</p>\u0000 </div>","PeriodicalId":15552,"journal":{"name":"Journal of Comparative Neurology","volume":"534 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148784825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hindlimb Representation in the Spiny Mouse Sensorimotor Cortex","authors":"Anton Beljajev,&nbsp;Aleksandr Veshchitskii,&nbsp;Aleksandr Mikhalkin,&nbsp;Polina Shkorbatova,&nbsp;Natalia Merkulyeva","doi":"10.1002/cne.70194","DOIUrl":"10.1002/cne.70194","url":null,"abstract":"<div>\u0000 \u0000 <p>The Cairo spiny mouse (<i>Acomys cahirinus</i>), a promising animal model in neuroscience, lacks a detailed neuroanatomical map of its cerebral cortex. This study aims to delineate the location and internal subdivision of the sensorimotor cortex, specifically the region controlling the hindlimb. For this purpose, retrograde tracing from the lumbar spinal cord using Fast Blue was combined with immunohistochemical characterization using neuronal markers (NeuN, SMI-32, and calbindin 28 kDa) in adult animals. Fast Blue-labeled neurons were identified in layer V within the cortical region defined as the sensorimotor cortex responsible for hindlimb control. Within this region, the general cytoarchitecture was defined using NeuN, which allowed visualization of all cortical layers. The border between the lateral and medial sub-areas was clearly identified by SMI-32 immunostaining, which showed denser labeling in the lateral zone (presumably the primary somatosensory cortex) compared to the medial zone (presumably the secondary motor cortex). Within the defined layers and sub-areas, a comprehensive analysis of the calbindin-expressing interneuron population was performed, revealing significant interareal differences in soma size and cellular density of calbindin-positive neurons exclusively within layers III–IV. These findings provide the first detailed map of the hindlimb sensorimotor cortex in spiny mice, establishing a crucial neuroanatomical foundation for future studies using this novel model in sensorimotor research.</p>\u0000 </div>","PeriodicalId":15552,"journal":{"name":"Journal of Comparative Neurology","volume":"534 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148697543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Brain-Wide Mapping and Synaptic Localization of C1QL3 Using a Novel Epitope-Tagged Knock-In Mouse","authors":"William P. Armstrong IV,&nbsp;James M. Salvatore,&nbsp;Matthew J. Sticco,&nbsp;Keaven Caro,&nbsp;J. Wesley Maddox,&nbsp;Angie Huang,&nbsp;Brenna C. McAllister,&nbsp;Christopher B. O'Connell,&nbsp;Siu-Pok Yee,&nbsp;Amy Lee,&nbsp;Susanne Ressl,&nbsp;David C. Martinelli,&nbsp;Alexander C. Jackson","doi":"10.1002/cne.70193","DOIUrl":"10.1002/cne.70193","url":null,"abstract":"<p>Synapse formation and function are coordinated spatially and temporally by a host of synaptic proteins that regulate neuronal signaling, synapse specificity, and plasticity, many of which are implicated in neuropsychiatric disorders. Many members of the C1q/TNF superfamily function as synaptic organizers, shaping synapse assembly and maintenance. Among them, C1QL3 plays a putative role in trans-synaptic adhesion and modulation of synaptic strength, but the lack of a reliable antibody to detect it has severely limited the ability to map its endogenous localization and study its biochemical properties. Here, we present a novel epitope-tagged knock-in mouse line (<i>C1ql3</i>^2HA), in which two hemagglutinin (HA) epitopes were inserted near the N-terminus of the endogenous C1QL3 protein. This model enables purification, detection, and subcellular localization of native C1QL3 protein (C1QL3-2HA) with high specificity, eliminating the need for overexpression or custom antibodies. We validated that <i>C1ql3</i>^2HA mice maintain normal mRNA expression, biochemical properties, and behavior. Using native PAGE, we determined the endogenous oligomeric state of C1QL3-2HA. Brain-wide light-sheet microscopy uncovered an expanded neuroanatomical map of C1QL3-2HA expression, including newly identified populations in cortical and subcortical regions as well as the retina. Dual immunohistochemistry confirmed cell-type-specific expression patterns, and super-resolution STED microscopy localized C1QL3-2HA to hippocampal mossy fiber synapses, positioned between pre- and postsynaptic markers, supporting its hypothesized role in trans-synaptic complexes. This knock-in mouse line is a valuable tool for studying the anatomical, molecular, and synaptic biology of C1QL3 in all cellular/tissue contexts, enabling future studies into its potential roles in the nervous system and beyond.</p>","PeriodicalId":15552,"journal":{"name":"Journal of Comparative Neurology","volume":"534 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13449632/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148684697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular Ontology Predicts Output Connections From the Nucleus of the Solitary Tract","authors":"Silvia Gasparini,&nbsp;Haidong Zhu,&nbsp;Ana Sofia Peraza Munuzuri,&nbsp;Mya L. Leuang,&nbsp;Frederico S. Fazan,&nbsp;Joel C. Geerling","doi":"10.1002/cne.70188","DOIUrl":"10.1002/cne.70188","url":null,"abstract":"<p>Understanding how the brain processes bodily signals requires mapping the circuits that transform interoceptive information into coordinated responses. Visceral signals converge in the nucleus of the solitary tract (NTS), which coordinates appetite, breathing, cardiovascular reflexes, and digestion. The NTS contains many intermingled subpopulations of neurons, and deciphering their functions requires understanding their connections. Here, we used cell-type-specific tracing to test whether molecularly distinct NTS neurons exhibit unique connectivity patterns. First, we found that <i>Lmx1b</i>-expressing excitatory neurons provide output to a broad array of NTS target regions in both the brainstem and forebrain, while inhibitory neurons in this region project predominantly within the brainstem. Next, we found that several genetically defined excitatory subpopulations—catecholaminergic (<i>Th</i>), neuropeptidergic (<i>Cck</i>, <i>Npff</i>, or <i>Pdyn</i>), and aldosterone-sensitive (<i>Hsd11b2</i>)—exhibit unique output patterns across multiple targets. As examples, the ventrolateral medulla receives moderate <i>Th</i>, <i>Cck</i>, and <i>Pdyn</i>, light <i>Npff</i>, and no <i>Hsd11b2</i> input. The outer rim of the external lateral parabrachial subnucleus receives concentrated <i>Th</i>, <i>Cck</i>, and <i>Npff</i> input, contrasting a more uniform <i>Pdyn</i> input and a lack of <i>Hsd11b2</i> input. The subcommissural bed nucleus of the stria terminalis receives broad <i>Th</i>, light <i>Cck</i>, sparse <i>Pdyn</i>, and virtually no <i>Npff</i> input, contrasting the focal <i>Hsd11b2</i> input to its fusiform subnucleus. These divergent patterns demonstrate that molecular identity predicts connectivity and define the organizational logic by which interoceptive signals are transformed into coordinated autonomic and behavioral responses.</p>","PeriodicalId":15552,"journal":{"name":"Journal of Comparative Neurology","volume":"534 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13446619/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148684758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Connections of the Telencephalic Pallium in the White Sturgeon, Acipenser transmontanus: An Experimental Study","authors":"R. Glenn Northcutt","doi":"10.1002/cne.70185","DOIUrl":"10.1002/cne.70185","url":null,"abstract":"<p>Sturgeons are an ancient and basal group of ray-finned fishes whose morphology is critical to our understanding of the evolution of teleosts, which form most of the ray-finned fish radiation. In sturgeons, the pallium, or area dorsalis, consists of lateral, medial, and posterior divisions. The connections of these pallial divisions were determined by injections of biotinylated dextran amine and DiI. All three divisions receive olfactory input, with the posterior division receiving the bulk of the secondary olfactory projections. All three pallial divisions also have extensive intratelencephalic connections, as well as input from the thalamus and the posterior tubercle. The posterior division also receives sparse input from the midbrain and secondary gustatory nucleus of the isthmus. All three pallial divisions project heavily to the hypothalamus of the ipsilateral inferior lobe, and more sparsely to the ipsilateral optic tectum, posterior tubercle, and midbrain tegmentum. Cytological and connectional data provide no evidence that either a dorsal or central pallial division exists in sturgeons, and these pallial divisions likely arose in ancestral teleosts.</p>","PeriodicalId":15552,"journal":{"name":"Journal of Comparative Neurology","volume":"534 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13428620/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148653760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regional Functional Molecular Profiles Within the Mammalian Cortex: A Commentary on Limbic Mesocortex","authors":"Luis Puelles,&nbsp;Elena Garcia-Calero","doi":"10.1002/cne.70191","DOIUrl":"https://doi.org/10.1002/cne.70191","url":null,"abstract":"<p>Two lateral mouse brain sagittal sections labeled, respectively, for <i>Lypd1</i> (A) and <i>Kcnab3</i> (B). (A) <i>Lypd1</i> labels <i>positively</i> cortical Layers 2 and 5 (less heavily), but only at limbic mesocortical sites, forming the limbic ring that separates the unlabeled isocortex (IsoCx) from the unlabeled hippocampal and olfactory allocortex (Hi, Sub, ERh; OlfCx). The limbic ring is marked twice as the insula (Ins, MCx) and the postrhinal area (PoRh, MCx). (B) <i>Kcnab3</i>, contrarily, labels selectively various layers of the isocortex (IsoCx) and the hippocampal allocortex (Hi, Sub, ERh) but leaves unlabeled selectively the insula (Ins, MCx) and postrhinal (PoRh, MCx) areas of the limbic mesocortical ring, being thus a <i>negative</i> marker for this sort of cortex.\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":15552,"journal":{"name":"Journal of Comparative Neurology","volume":"534 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cne.70191","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148616497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative Neuroanatomy of Hydrothermal Vent Shrimps: Ecological Differentiation Among Four Alvinocaridid Species","authors":"Adrien Mathou,&nbsp;Julia Machon,&nbsp;Rebecca Meth,&nbsp;Magali Zbinden,&nbsp;Juliette Ravaux,&nbsp;Steffen Harzsch","doi":"10.1002/cne.70190","DOIUrl":"10.1002/cne.70190","url":null,"abstract":"<p>Alvinocaridid shrimps colonize hydrothermal vent fields along the Mid-Atlantic Ridge (MAR), where they experience extreme environmental conditions including high hydrostatic pressure, steep thermal and chemical gradients, and dim light. While various aspects of the biology of the dominant vent shrimp <i>Rimicaris exoculata</i>, such as general anatomy, microhabitat, symbiotic relationships, or trophic networks, have been extensively studied, little is known about how brain organization varies among alvinocaridid species occupying different ecological niches. Here, we investigated whether vent shrimps share common neuroanatomical features and whether differences in brain and vascular organization reflect ecological diversification among species. Using histology, immunohistochemistry, µCT scans, and 3D reconstruction, we compared the brain and the neurovascular system (<i>cor frontale</i>) in four MAR species with distinct ecologies (<i>R. exoculata</i>, <i>Rimicaris chacei</i>, <i>Mirocaris fortunata</i>, <i>Alvinocaris markensis</i>) and in the coastal relative <i>Palaemon elegans</i>. Our results reveal strong commonalities in brain organization among vent shrimps. All MAR species display a compact brain architecture with hypertrophied mushroom bodies (MBs), suggesting enhanced multisensory integration and memory capacities. Corresponding to the low-light environment, the visual neuropils (lamina, medulla, lobula) are smaller than those of the coastal species <i>P. elegans</i>. In all species living near hydrothermal vents, the retina exhibits modifications; it extends along the dorsal part of the cephalothorax, and its length varies according to the species, being the longest in the genus <i>Rimicaris</i>. The lobula satellite neuropil is absent in all alvinocaridids, suggesting a limited capacity to track moving visual signals. The olfactory lobes exhibit a common glomerular organization but differ among species in quantitative parameters, such as volume and number of glomeruli. The neurovascular system shows marked interspecific variation; the <i>cor frontale</i> differs in size and volume among hydrothermal vent species but retains a conserved subdivision of central arteries surrounding a longitudinal muscle bundle. We conclude that the observed variations in the volume of neuropils and arrangement of the vascular system likely reflect the ecological divergence related to microhabitat conditions and trophic strategies near hydrothermal emissions.</p>","PeriodicalId":15552,"journal":{"name":"Journal of Comparative Neurology","volume":"534 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cne.70190","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148604073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anatomical Characteristics of Tongue-Innervating Mechanoreceptors","authors":"Thomas A. Myers,&nbsp;Madison Sneve,&nbsp;Robin F. Krimm","doi":"10.1002/cne.70186","DOIUrl":"10.1002/cne.70186","url":null,"abstract":"<div>\u0000 \u0000 <p>Mechanosensory innervation of the oral cavity enables us to detect the texture and location of the foods we consume. Our goal was to find a genetic identifier for a mechanoreceptive subtype. Toward this goal, we examined neurons expressing the neurotrophin receptor TrkC (TrkC-tdTomato), parvalbumin (Pvalb), or glutamate transporter, Vglut3. We found that the majority of Pvalb-lineage, Vglut3-lineage, and TrkC-tdTomato neurons innervating the tongue are separate trigeminal neuron populations. Because different papilla types contribute to food detection in different ways, we examined the innervation patterns of these neuron subtypes. We found that Pvalb-lineage and Vglut3-lineage neurons were fungiform papilla-specific, whereas TrkC+ fibers innervated both papilla types. We found that all Pvalb-lineage nerve fibers are labeled with neurofilament heavy chain (NFH), have axons that are surrounded by myelin basic protein, and lack calcitonin gene-related peptide. This indicates that these are all myelinated neurons. In contrast, Vglut3-lineage and TrkC-tdTomato nerve fibers were a mixed population of NFH+ nerve fibers and NFH− nerve fibers, as well as myelinated and unmyelinated nerve fibers. When we examined the axonal ending morphologies of the three genetic populations, we found that the Pvalb-lineage neurons consistently displayed a “basket-like” axonal ending that surrounded the taste bud. While TrkC+ and Vglut3-lineage neurons sometimes displayed this “basket-like” axonal ending, other axonal endings lacked this structure. When compared across groups, the Vglut3-lineage axonal endings displayed the greatest degree of morphological variability. Collectively, these data show that Pvalb-lineage may be a genetic identifier for a single myelinated mechanoreceptor innervating fungiform papillae.</p>\u0000 </div>","PeriodicalId":15552,"journal":{"name":"Journal of Comparative Neurology","volume":"534 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148591981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}