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Maraslioglu-Sperber A, Pizzi E, Fisch JO, Kattler K, Ritter T, Friauf E. Molecular and functional profiling of cell diversity and identity in the lateral superior olive, an auditory brainstem center with ascending and descending projections. Front Cell Neurosci 2024; 18:1354520. [PMID: 38846638 PMCID: PMC11153811 DOI: 10.3389/fncel.2024.1354520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 03/15/2024] [Indexed: 06/09/2024] Open
Abstract
The lateral superior olive (LSO), a prominent integration center in the auditory brainstem, contains a remarkably heterogeneous population of neurons. Ascending neurons, predominantly principal neurons (pLSOs), process interaural level differences for sound localization. Descending neurons (lateral olivocochlear neurons, LOCs) provide feedback into the cochlea and are thought to protect against acoustic overload. The molecular determinants of the neuronal diversity in the LSO are largely unknown. Here, we used patch-seq analysis in mice at postnatal days P10-12 to classify developing LSO neurons according to their functional and molecular profiles. Across the entire sample (n = 86 neurons), genes involved in ATP synthesis were particularly highly expressed, confirming the energy expenditure of auditory neurons. Two clusters were identified, pLSOs and LOCs. They were distinguished by 353 differentially expressed genes (DEGs), most of which were novel for the LSO. Electrophysiological analysis confirmed the transcriptomic clustering. We focused on genes affecting neuronal input-output properties and validated some of them by immunohistochemistry, electrophysiology, and pharmacology. These genes encode proteins such as osteopontin, Kv11.3, and Kvβ3 (pLSO-specific), calcitonin-gene-related peptide (LOC-specific), or Kv7.2 and Kv7.3 (no DEGs). We identified 12 "Super DEGs" and 12 genes showing "Cluster similarity." Collectively, we provide fundamental and comprehensive insights into the molecular composition of individual ascending and descending neurons in the juvenile auditory brainstem and how this may relate to their specific functions, including developmental aspects.
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Affiliation(s)
- Ayse Maraslioglu-Sperber
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Erika Pizzi
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Jonas O. Fisch
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Kathrin Kattler
- Genetics/Epigenetics Group, Department of Biological Sciences, Saarland University, Saarbrücken, Germany
| | - Tamara Ritter
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Eckhard Friauf
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
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Beebe NL, Herrera YN, Noftz WA, Roberts MT, Schofield BR. Characterization of three cholinergic inputs to the cochlear nucleus. J Chem Neuroanat 2023; 131:102284. [PMID: 37164181 PMCID: PMC10330717 DOI: 10.1016/j.jchemneu.2023.102284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 05/02/2023] [Accepted: 05/03/2023] [Indexed: 05/12/2023]
Abstract
Acetylcholine modulates responses throughout the auditory system, including at the earliest brain level, the cochlear nucleus (CN). Previous studies have shown multiple sources of cholinergic input to the CN but information about their relative contributions and the distribution of inputs from each source is lacking. Here, we used staining for cholinergic axons and boutons, retrograde tract tracing, and acetylcholine-selective anterograde tracing to characterize three sources of acetylcholine input to the CN in mice. Staining for cholinergic axons showed heavy cholinergic inputs to granule cell areas and the dorsal CN with lighter input to the ventral CN. Retrograde tract tracing revealed that cholinergic cells from the superior olivary complex, pontomesencephalic tegmentum, and lateral paragigantocellular nucleus send projections to the CN. When we selectively labeled cholinergic axons from each source to the CN, we found surprising similarities in their terminal distributions, with patterns that were overlapping rather than complementary. Each source heavily targeted granule cell areas and the dorsal CN (especially the deep dorsal CN) and sent light input into the ventral CN. Our results demonstrate convergence of cholinergic inputs from multiple sources in most regions of the CN and raise the possibility of convergence onto single CN cells. Linking sources of acetylcholine and their patterns of activity to modulation of specific cell types in the CN will be an important next step in understanding cholinergic modulation of early auditory processing.
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Affiliation(s)
- Nichole L Beebe
- Hearing Research Group, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Yoani N Herrera
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI, USA
| | - William A Noftz
- Hearing Research Group, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Michael T Roberts
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Brett R Schofield
- Hearing Research Group, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA.
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Gómez-Martínez M, Rincón H, Gómez-Álvarez M, Gómez-Nieto R, Saldaña E. The nuclei of the lateral lemniscus: unexpected players in the descending auditory pathway. Front Neuroanat 2023; 17:1242245. [PMID: 37621862 PMCID: PMC10445163 DOI: 10.3389/fnana.2023.1242245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 07/10/2023] [Indexed: 08/26/2023] Open
Abstract
Introduction In the mammalian auditory pathway, the nuclei of the lateral lemniscus (NLL) are thought to be exclusively involved in the bottom-up transmission of auditory information. However, our repeated observation of numerous NLL neurons labeled after injection of retrograde tracers into the superior olivary complex (SOC) led us to systematically investigate with retrograde tracers the descending projections from the NLL to the SOC of the rat. Methods We performed large injections of FluoroGold into the SOC to determine NLL contributions to descending projections, and focal injections of biotinylated dextran amine (BDA) to pinpoint the specific nuclei of the SOC innervated by each NLL. Results The SOC is innervated by thousands of neurons distributed across four nuclei or regions associated with the lateral lemniscus: the ipsilateral ventral and intermediate nuclei of the lateral lemniscus (VNLL and INLL); the medial paralemniscal region (PL) of both sides; and the ipsilateral semilunar nucleus (SLN), a previously unrecognized nucleus that wraps around the INLL dorsally, medially, and caudally and consists of small, flat neurons. In some experiments, at least 30% of neurons in the VNLL and INLL were retrogradely labeled. All nuclei of the SOC, except the medial and lateral superior olives, are innervated by abundant lemniscal neurons, and each SOC nucleus receives a unique combination of lemniscal inputs. The primary target of the projections from the VNLL is the ventral nucleus of the trapezoid body (VNTB), followed by the superior paraolivary nucleus (SPON), and the medial nucleus of the trapezoid body (MNTB). The INLL selectively innervates the VNTB. The PL innervates dorsal periolivary regions bilaterally. The SLN preferentially innervates the MNTB and may provide the first identified non-calyceal excitatory input to MNTB neurons. Discussion Our novel findings have strong implications for understanding acoustic information processing in the initial stages of the auditory pathway. Based on the proportion of lemniscal neurons involved in all the projections described, the NLL should be considered major players in the descending auditory pathway.
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Affiliation(s)
- Mario Gómez-Martínez
- Neuroscience Institute of Castilla y León, University of Salamanca, Salamanca, Spain
- Department of Cell Biology and Pathology, Medical School, University of Salamanca, Salamanca, Spain
- Institute of Biomedical Research of Salamanca, Salamanca, Spain
| | - Héctor Rincón
- Neuroscience Institute of Castilla y León, University of Salamanca, Salamanca, Spain
- Department of Cell Biology and Pathology, Medical School, University of Salamanca, Salamanca, Spain
- Institute of Biomedical Research of Salamanca, Salamanca, Spain
| | - Marcelo Gómez-Álvarez
- Neuroscience Institute of Castilla y León, University of Salamanca, Salamanca, Spain
- Department of Cell Biology and Pathology, Medical School, University of Salamanca, Salamanca, Spain
- Institute of Biomedical Research of Salamanca, Salamanca, Spain
| | - Ricardo Gómez-Nieto
- Neuroscience Institute of Castilla y León, University of Salamanca, Salamanca, Spain
- Department of Cell Biology and Pathology, Medical School, University of Salamanca, Salamanca, Spain
- Institute of Biomedical Research of Salamanca, Salamanca, Spain
| | - Enrique Saldaña
- Neuroscience Institute of Castilla y León, University of Salamanca, Salamanca, Spain
- Department of Cell Biology and Pathology, Medical School, University of Salamanca, Salamanca, Spain
- Institute of Biomedical Research of Salamanca, Salamanca, Spain
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Molecular Organization and Patterning of the Medulla Oblongata in Health and Disease. Int J Mol Sci 2022; 23:ijms23169260. [PMID: 36012524 PMCID: PMC9409237 DOI: 10.3390/ijms23169260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/15/2022] [Accepted: 08/16/2022] [Indexed: 11/17/2022] Open
Abstract
The medulla oblongata, located in the hindbrain between the pons and the spinal cord, is an important relay center for critical sensory, proprioceptive, and motoric information. It is an evolutionarily highly conserved brain region, both structural and functional, and consists of a multitude of nuclei all involved in different aspects of basic but vital functions. Understanding the functional anatomy and developmental program of this structure can help elucidate potential role(s) of the medulla in neurological disorders. Here, we have described the early molecular patterning of the medulla during murine development, from the fundamental units that structure the very early medullary region into 5 rhombomeres (r7–r11) and 13 different longitudinal progenitor domains, to the neuronal clusters derived from these progenitors that ultimately make-up the different medullary nuclei. By doing so, we developed a schematic overview that can be used to predict the cell-fate of a progenitor group, or pinpoint the progenitor domain of origin of medullary nuclei. This schematic overview can further be used to help in the explanation of medulla-related symptoms of neurodevelopmental disorders, e.g., congenital central hypoventilation syndrome, Wold–Hirschhorn syndrome, Rett syndrome, and Pitt–Hopkins syndrome. Based on the genetic defects seen in these syndromes, we can use our model to predict which medullary nuclei might be affected, which can be used to quickly direct the research into these diseases to the likely affected nuclei.
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Romero GE, Trussell LO. Central circuitry and function of the cochlear efferent systems. Hear Res 2022; 425:108516. [DOI: 10.1016/j.heares.2022.108516] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 04/28/2022] [Accepted: 05/10/2022] [Indexed: 11/04/2022]
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Vicencio-Jimenez S, Weinberg MM, Bucci-Mansilla G, Lauer AM. Olivocochlear Changes Associated With Aging Predominantly Affect the Medial Olivocochlear System. Front Neurosci 2021; 15:704805. [PMID: 34539335 PMCID: PMC8446540 DOI: 10.3389/fnins.2021.704805] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 08/02/2021] [Indexed: 11/13/2022] Open
Abstract
Age-related hearing loss (ARHL) is a public health problem that has been associated with negative health outcomes ranging from increased frailty to an elevated risk of developing dementia. Significant gaps remain in our knowledge of the underlying central neural mechanisms, especially those related to the efferent auditory pathways. Thus, the aim of this study was to quantify and compare age-related alterations in the cholinergic olivocochlear efferent auditory neurons. We assessed, in young-adult and aged CBA mice, the number of cholinergic olivocochlear neurons, auditory brainstem response (ABR) thresholds in silence and in presence of background noise, and the expression of excitatory and inhibitory proteins in the ventral nucleus of the trapezoid body (VNTB) and in the lateral superior olive (LSO). In association with aging, we found a significant decrease in the number of medial olivocochlear (MOC) cholinergic neurons together with changes in the ratio of excitatory and inhibitory proteins in the VNTB. Furthermore, in old mice we identified a correlation between the number of MOC neurons and ABR thresholds in the presence of background noise. In contrast, the alterations observed in the lateral olivocochlear (LOC) system were less significant. The decrease in the number of LOC cells associated with aging was 2.7-fold lower than in MOC and in the absence of changes in the expression of excitatory and inhibitory proteins in the LSO. These differences suggest that aging alters the medial and lateral olivocochlear efferent pathways in a differential manner and that the changes observed may account for some of the symptoms seen in ARHL.
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Affiliation(s)
- Sergio Vicencio-Jimenez
- The Center for Hearing and Balance, Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Madison M Weinberg
- The Center for Hearing and Balance, Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Giuliana Bucci-Mansilla
- Laboratorio de Neurosistemas, Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Amanda M Lauer
- The Center for Hearing and Balance, Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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