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Oliver Goral R, Lamb PW, Yakel JL. Acetylcholine Neurons Become Cholinergic during Three Time Windows in the Developing Mouse Brain. eNeuro 2024; 11:ENEURO.0542-23.2024. [PMID: 38942474 PMCID: PMC11253243 DOI: 10.1523/eneuro.0542-23.2024] [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: 12/19/2023] [Revised: 06/12/2024] [Accepted: 06/22/2024] [Indexed: 06/30/2024] Open
Abstract
Acetylcholine (ACh) neurons in the central nervous system are required for the coordination of neural network activity during higher brain functions, such as attention, learning, and memory, as well as locomotion. Disturbed cholinergic signaling has been described in many neurodevelopmental and neurodegenerative disorders. Furthermore, cotransmission of other signaling molecules, such as glutamate and GABA, with ACh has been associated with essential roles in brain function or disease. However, it is unknown when ACh neurons become cholinergic during development. Thus, understanding the timeline of how the cholinergic system develops and becomes active in the healthy brain is a crucial part of understanding brain development. To study this, we used transgenic mice to selectively label ACh neurons with tdTomato. We imaged serial sectioned brains and generated whole-brain reconstructions at different time points during pre- and postnatal development. We found three crucial time windows-two in the prenatal and one in the postnatal brain-during which most ACh neuron populations become cholinergic in the brain. We also found that cholinergic gene expression is initiated in cortical ACh interneurons, while the cerebral cortex is innervated by cholinergic projection neurons from the basal forebrain. Taken together, we show that ACh neuron populations are present and become cholinergic before postnatal day 12, which is the onset of major sensory processes, such as hearing and vision. We conclude that the birth of ACh neurons and initiation of cholinergic gene expression are temporally separated during development but highly coordinated by brain anatomical structure.
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Affiliation(s)
- Rene Oliver Goral
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
- Center on Compulsive Behaviors, National Institutes of Health, Bethesda, Maryland 20892
| | - Patricia W Lamb
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
| | - Jerrel L Yakel
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
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2
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van Velthoven CTJ, Gao Y, Kunst M, Lee C, McMillen D, Chakka AB, Casper T, Clark M, Chakrabarty R, Daniel S, Dolbeare T, Ferrer R, Gloe J, Goldy J, Guzman J, Halterman C, Ho W, Huang M, James K, Nguy B, Pham T, Ronellenfitch K, Thomas ED, Torkelson A, Pagan CM, Kruse L, Dee N, Ng L, Waters J, Smith KA, Tasic B, Yao Z, Zeng H. The transcriptomic and spatial organization of telencephalic GABAergic neuronal types. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.18.599583. [PMID: 38948843 PMCID: PMC11212977 DOI: 10.1101/2024.06.18.599583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
The telencephalon of the mammalian brain comprises multiple regions and circuit pathways that play adaptive and integrative roles in a variety of brain functions. There is a wide array of GABAergic neurons in the telencephalon; they play a multitude of circuit functions, and dysfunction of these neurons has been implicated in diverse brain disorders. In this study, we conducted a systematic and in-depth analysis of the transcriptomic and spatial organization of GABAergic neuronal types in all regions of the mouse telencephalon and their developmental origins. This was accomplished by utilizing 611,423 single-cell transcriptomes from the comprehensive and high-resolution transcriptomic and spatial cell type atlas for the adult whole mouse brain we have generated, supplemented with an additional single-cell RNA-sequencing dataset containing 99,438 high-quality single-cell transcriptomes collected from the pre- and postnatal developing mouse brain. We present a hierarchically organized adult telencephalic GABAergic neuronal cell type taxonomy of 7 classes, 52 subclasses, 284 supertypes, and 1,051 clusters, as well as a corresponding developmental taxonomy of 450 clusters across different ages. Detailed charting efforts reveal extraordinary complexity where relationships among cell types reflect both spatial locations and developmental origins. Transcriptomically and developmentally related cell types can often be found in distant and diverse brain regions indicating that long-distance migration and dispersion is a common characteristic of nearly all classes of telencephalic GABAergic neurons. Additionally, we find various spatial dimensions of both discrete and continuous variations among related cell types that are correlated with gene expression gradients. Lastly, we find that cortical, striatal and some pallidal GABAergic neurons undergo extensive postnatal diversification, whereas septal and most pallidal GABAergic neuronal types emerge simultaneously during the embryonic stage with limited postnatal diversification. Overall, the telencephalic GABAergic cell type taxonomy can serve as a foundational reference for molecular, structural and functional studies of cell types and circuits by the entire community.
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Affiliation(s)
| | - Yuan Gao
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Changkyu Lee
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | | | | | | | | | - Scott Daniel
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Tim Dolbeare
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Jessica Gloe
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Jeff Goldy
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | | | - Windy Ho
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Mike Huang
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Beagan Nguy
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | | | | | | | | | - Lauren Kruse
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Nick Dee
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Lydia Ng
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Jack Waters
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | | | - Zizhen Yao
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Hongkui Zeng
- Allen Institute for Brain Science, Seattle, WA, USA
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3
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Lozovaya N, Moumen A, Hammond C. Basal Forebrain Cholinergic Neurons Have Specific Characteristics during the Perinatal Period. eNeuro 2024; 11:ENEURO.0538-23.2024. [PMID: 38755010 PMCID: PMC11137802 DOI: 10.1523/eneuro.0538-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 04/09/2024] [Accepted: 05/05/2024] [Indexed: 05/18/2024] Open
Abstract
Cholinergic neurons of the basal forebrain represent the main source of cholinergic innervation of large parts of the neocortex and are involved in adults in the modulation of attention, memory, and arousal. During the first postnatal days, they play a crucial role in the development of cortical neurons and cortical cytoarchitecture. However, their characteristics, during this period have not been studied. To understand how they can fulfill this role, we investigated the morphological and electrophysiological maturation of cholinergic neurons of the substantia innominata-nucleus basalis of Meynert (SI/NBM) complex in the perinatal period in mice. We show that cholinergic neurons, whether or not they express gamma-aminobutyric acid (GABA) as a cotransmitter, are already functional at Embryonic Day 18. Until the end of the first postnatal week, they constitute a single population of neurons with a well developed dendritic tree, a spontaneous activity including bursting periods, and a short-latency response to depolarizations (early-firing). They are excited by both their GABAergic and glutamatergic afferents. During the second postnatal week, a second, less excitable, neuronal population emerges, with a longer delay response to depolarizations (late-firing), together with the hyperpolarizing action of GABAA receptor-mediated currents. This classification into early-firing (40%) and late-firing (60%) neurons is again independent of the coexpression of GABAergic markers. These results strongly suggest that during the first postnatal week, the specific properties of developing SI/NBM cholinergic neurons allow them to spontaneously release acetylcholine (ACh), or ACh and GABA, into the developing cortex.
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4
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Kim R, Ananth MR, Desai NS, Role LW, Talmage DA. Distinct subpopulations of ventral pallidal cholinergic projection neurons encode valence of olfactory stimuli. Cell Rep 2024; 43:114009. [PMID: 38536818 PMCID: PMC11080946 DOI: 10.1016/j.celrep.2024.114009] [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: 10/18/2023] [Revised: 03/08/2024] [Accepted: 03/13/2024] [Indexed: 04/09/2024] Open
Abstract
To better understand the function of cholinergic projection neurons in the ventral pallidum (VP), we examined behavioral responses to appetitive (APP) and aversive (AV) odors that elicited approach or avoidance, respectively. Exposure to each odor increased cFos expression and calcium signaling in VP cholinergic neurons. Activity and Cre-dependent viral vectors selectively labeled VP cholinergic neurons that were activated and reactivated in response to either APP or AV odors, but not both, identifying two non-overlapping populations of VP cholinergic neurons differentially activated by the valence of olfactory stimuli. These two subpopulations showed differences in electrophysiological properties, morphology, and projections to the basolateral amygdala. Although VP neurons are engaged in both approach and avoidance behavioral responses, cholinergic signaling is only required for approach behavior. Thus, two distinct subpopulations of VP cholinergic neurons differentially encode valence of olfactory stimuli and play distinct roles in approach and avoidance behaviors.
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Affiliation(s)
- Ronald Kim
- Genetics of Neuronal Signaling Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mala R Ananth
- Circuits, Synapses and Molecular Signaling Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Niraj S Desai
- Circuits, Synapses and Molecular Signaling Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lorna W Role
- Circuits, Synapses and Molecular Signaling Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
| | - David A Talmage
- Genetics of Neuronal Signaling Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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5
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Kimchi EY, Burgos-Robles A, Matthews GA, Chakoma T, Patarino M, Weddington JC, Siciliano C, Yang W, Foutch S, Simons R, Fong MF, Jing M, Li Y, Polley DB, Tye KM. Reward contingency gates selective cholinergic suppression of amygdala neurons. eLife 2024; 12:RP89093. [PMID: 38376907 PMCID: PMC10942609 DOI: 10.7554/elife.89093] [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] [Indexed: 02/21/2024] Open
Abstract
Basal forebrain cholinergic neurons modulate how organisms process and respond to environmental stimuli through impacts on arousal, attention, and memory. It is unknown, however, whether basal forebrain cholinergic neurons are directly involved in conditioned behavior, independent of secondary roles in the processing of external stimuli. Using fluorescent imaging, we found that cholinergic neurons are active during behavioral responding for a reward - even prior to reward delivery and in the absence of discrete stimuli. Photostimulation of basal forebrain cholinergic neurons, or their terminals in the basolateral amygdala (BLA), selectively promoted conditioned responding (licking), but not unconditioned behavior nor innate motor outputs. In vivo electrophysiological recordings during cholinergic photostimulation revealed reward-contingency-dependent suppression of BLA neural activity, but not prefrontal cortex. Finally, ex vivo experiments demonstrated that photostimulation of cholinergic terminals suppressed BLA projection neuron activity via monosynaptic muscarinic receptor signaling, while also facilitating firing in BLA GABAergic interneurons. Taken together, we show that the neural and behavioral effects of basal forebrain cholinergic activation are modulated by reward contingency in a target-specific manner.
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Affiliation(s)
- Eyal Y Kimchi
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
- Department of Neurology, Northwestern UniversityChicagoUnited States
| | - Anthony Burgos-Robles
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
- The Department of Neuroscience, Developmental, and Regenerative Biology, Neuroscience Institute & Brain Health Consortium, University of Texas at San AntonioSan AntonioUnited States
| | - Gillian A Matthews
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Tatenda Chakoma
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Makenzie Patarino
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Javier C Weddington
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Cody Siciliano
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
- Vanderbilt Center for Addiction Research, Department of Pharmacology, Vanderbilt UniversityNashvilleUnited States
| | - Wannan Yang
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Shaun Foutch
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Renee Simons
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Ming-fai Fong
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
- Coulter Department of Biomedical Engineering, Georgia Tech & Emory UniversityAtlantaUnited States
| | - Miao Jing
- Chinese Institute for Brain ResearchBeijingChina
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences; PKUIDG/McGovern Institute for Brain Research; Peking-Tsinghua Center for Life SciencesBeijingChina
| | - Daniel B Polley
- Eaton-Peabody Laboratories, Massachusetts Eye and EarBostonUnited States
- Department of Otolaryngology – Head and Neck Surgery, Harvard Medical SchoolBostonUnited States
| | - Kay M Tye
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridgeUnited States
- HHMI Investigator, Member of the Kavli Institute for Brain and Mind, and Wylie Vale Professor at the Salk Institute for Biological StudiesLa JollaUnited States
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6
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Huang S, Wu SJ, Sansone G, Ibrahim LA, Fishell G. Layer 1 neocortex: Gating and integrating multidimensional signals. Neuron 2024; 112:184-200. [PMID: 37913772 PMCID: PMC11180419 DOI: 10.1016/j.neuron.2023.09.041] [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: 07/24/2023] [Revised: 09/23/2023] [Accepted: 09/28/2023] [Indexed: 11/03/2023]
Abstract
Layer 1 (L1) of the neocortex acts as a nexus for the collection and processing of widespread information. By integrating ascending inputs with extensive top-down activity, this layer likely provides critical information regulating how the perception of sensory inputs is reconciled with expectation. This is accomplished by sorting, directing, and integrating the complex network of excitatory inputs that converge onto L1. These signals are combined with neuromodulatory afferents and gated by the wealth of inhibitory interneurons that either are embedded within L1 or send axons from other cortical layers. Together, these interactions dynamically calibrate information flow throughout the neocortex. This review will primarily focus on L1 within the primary sensory cortex and will use these insights to understand L1 in other cortical areas.
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Affiliation(s)
- Shuhan Huang
- Harvard Medical School, Blavatnik Institute, Department of Neurobiology, Boston, MA 02115, USA; Program in Neuroscience, Harvard University, Cambridge, MA 02138, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Sherry Jingjing Wu
- Harvard Medical School, Blavatnik Institute, Department of Neurobiology, Boston, MA 02115, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Giulia Sansone
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Leena Ali Ibrahim
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia.
| | - Gord Fishell
- Harvard Medical School, Blavatnik Institute, Department of Neurobiology, Boston, MA 02115, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
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7
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Glanz RM, Sokoloff G, Blumberg MS. Neural decoding reveals specialized kinematic tuning after an abrupt cortical transition. Cell Rep 2023; 42:113119. [PMID: 37690023 PMCID: PMC10591925 DOI: 10.1016/j.celrep.2023.113119] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 06/08/2023] [Accepted: 08/24/2023] [Indexed: 09/12/2023] Open
Abstract
The primary motor cortex (M1) exhibits a protracted period of development, including the development of a sensory representation long before motor outflow emerges. In rats, this representation is present by postnatal day (P) 8, when M1 activity is "discontinuous." Here, we ask how the representation changes upon the transition to "continuous" activity at P12. We use neural decoding to predict forelimb movements from M1 activity and show that a linear decoder effectively predicts limb movements at P8 but not at P12; instead, a nonlinear decoder better predicts limb movements at P12. The altered decoder performance reflects increased complexity and uniqueness of kinematic information in M1. We next show that M1's representation at P12 is more susceptible to "lesioning" of inputs and "transplanting" of M1's encoding scheme from one pup to another. Thus, the emergence of continuous M1 activity signals the developmental onset of more complex, informationally sparse, and individualized sensory representations.
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Affiliation(s)
- Ryan M Glanz
- Department of Psychological & Brain Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - Greta Sokoloff
- Department of Psychological & Brain Sciences, University of Iowa, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Mark S Blumberg
- Department of Psychological & Brain Sciences, University of Iowa, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA.
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8
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Schlingloff D, Hangya B, Pinto L. A cholinergic auditory pathway. Nat Neurosci 2023; 26:726-728. [PMID: 37029204 DOI: 10.1038/s41593-023-01300-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2023]
Affiliation(s)
- Dániel Schlingloff
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
| | - Balázs Hangya
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary.
| | - Lucas Pinto
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL, USA.
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9
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Ananth MR, Rajebhosale P, Kim R, Talmage DA, Role LW. Basal forebrain cholinergic signalling: development, connectivity and roles in cognition. Nat Rev Neurosci 2023; 24:233-251. [PMID: 36823458 PMCID: PMC10439770 DOI: 10.1038/s41583-023-00677-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 01/18/2023] [Indexed: 02/25/2023]
Abstract
Acetylcholine plays an essential role in fundamental aspects of cognition. Studies that have mapped the activity and functional connectivity of cholinergic neurons have shown that the axons of basal forebrain cholinergic neurons innervate the pallium with far more topographical and functional organization than was historically appreciated. Together with the results of studies using new probes that allow release of acetylcholine to be detected with high spatial and temporal resolution, these findings have implicated cholinergic networks in 'binding' diverse behaviours that contribute to cognition. Here, we review recent findings on the developmental origins, connectivity and function of cholinergic neurons, and explore the participation of cholinergic signalling in the encoding of cognition-related behaviours.
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Affiliation(s)
- Mala R Ananth
- Section on Circuits, Synapses, and Molecular Signalling, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
| | - Prithviraj Rajebhosale
- Section on Genetics of Neuronal Signalling, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Ronald Kim
- Section on Genetics of Neuronal Signalling, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - David A Talmage
- Section on Genetics of Neuronal Signalling, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Lorna W Role
- Section on Circuits, Synapses, and Molecular Signalling, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
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10
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Paronett EM, Bryan CA, Maynard TM, LaMantia AS. Identity, lineage and fates of a temporally distinct progenitor population in the embryonic olfactory epithelium. Dev Biol 2023; 495:76-91. [PMID: 36627077 PMCID: PMC9926479 DOI: 10.1016/j.ydbio.2023.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 12/29/2022] [Accepted: 01/01/2023] [Indexed: 01/09/2023]
Abstract
We defined a temporally and transcriptionally divergent precursor cohort in the medial olfactory epithelium (OE) shortly after it differentiates as a distinct tissue at mid-gestation in the mouse. This temporally distinct population of Ascl1+ cells in the dorsomedial OE is segregated from Meis1+/Pax7+ progenitors in the lateral OE, and does not appear to be generated by Pax7+ lateral OE precursors. The medial Ascl1+ precursors do not yield a substantial number of early-generated ORNs. Instead, they first generate additional proliferative precursors as well as a distinct population of frontonasal mesenchymal cells associated with the migratory mass that surrounds the nascent olfactory nerve. Parallel to these in vivo distinctions, isolated medial versus lateral OE precursors in vitro retain distinct proliferative capacities and modes of division that reflect their in vivo identities. At later fetal stages, these early dorsomedial Ascl1+ precursors cells generate spatially restricted subsets of ORNs as well as other non-neuronal cell classes. Accordingly, the initial compliment of ORNs and other OE cell types is derived from at least two distinct early precursor populations: lateral Meis1/Pax7+ precursors that generate primarily early ORNs, and a temporally, spatially, and transcriptionally distinct subset of medial Ascl1+ precursors that initially generate additional OE progenitors and apparent migratory mass cells before yielding a subset of ORNs and likely supporting cell classes.
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Affiliation(s)
- Elizabeth M Paronett
- Department of Pharmacology and Physiology, George Washington University School of Medicine, Washington, DC, 20037, USA
| | - Corey A Bryan
- Laboratory of Developmental Disorders and Genetics, The Fralin Biomedical Research Institute, Virginia Tech-Carilion School of Medicine, Roanoke, VA, USA
| | - Thomas M Maynard
- Center for Neurobiology Research, The Fralin Biomedical Research Institute, Virginia Tech-Carilion School of Medicine, Roanoke, VA, USA
| | - Anthony-S LaMantia
- Center for Neurobiology Research, The Fralin Biomedical Research Institute, Virginia Tech-Carilion School of Medicine, Roanoke, VA, USA; Department of Biological Sciences Virginia Tech, Blacksburg, VA, USA.
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11
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Glanz R, Sokoloff G, Blumberg MS. Cortical Representation of Movement Across the Developmental Transition to Continuous Neural Activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.22.525085. [PMID: 36711887 PMCID: PMC9882351 DOI: 10.1101/2023.01.22.525085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Primary motor cortex (M1) exhibits a protracted period of development that includes the establishment of a somatosensory map long before motor outflow emerges. In rats, the sensory representation is established by postnatal day (P) 8 when cortical activity is still "discontinuous." Here, we ask how the representation survives the sudden transition to noisy "continuous" activity at P12. Using neural decoding to predict forelimb movements based solely on M1 activity, we show that a linear decoder is sufficient to predict limb movements at P8, but not at P12; in contrast, a nonlinear decoder effectively predicts limb movements at P12. The change in decoder performance at P12 reflects an increase in both the complexity and uniqueness of kinematic information available in M1. We next show that the representation at P12 is more susceptible to the deleterious effects of "lesioning" inputs and to "transplanting" M1's encoding scheme from one pup to another. We conclude that the emergence of continuous cortical activity signals the developmental onset in M1 of more complex, informationally sparse, and individualized sensory representations.
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Affiliation(s)
- Ryan Glanz
- Department of Psychological & Brain Sciences, University of Iowa, Iowa City, IA 52242 USA
| | - Greta Sokoloff
- Department of Psychological & Brain Sciences, University of Iowa, Iowa City, IA 52242 USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242 USA
| | - Mark S. Blumberg
- Department of Psychological & Brain Sciences, University of Iowa, Iowa City, IA 52242 USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242 USA
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12
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Mikulasch FA, Rudelt L, Wibral M, Priesemann V. Where is the error? Hierarchical predictive coding through dendritic error computation. Trends Neurosci 2023; 46:45-59. [PMID: 36577388 DOI: 10.1016/j.tins.2022.09.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 09/28/2022] [Accepted: 09/28/2022] [Indexed: 11/19/2022]
Abstract
Top-down feedback in cortex is critical for guiding sensory processing, which has prominently been formalized in the theory of hierarchical predictive coding (hPC). However, experimental evidence for error units, which are central to the theory, is inconclusive and it remains unclear how hPC can be implemented with spiking neurons. To address this, we connect hPC to existing work on efficient coding in balanced networks with lateral inhibition and predictive computation at apical dendrites. Together, this work points to an efficient implementation of hPC with spiking neurons, where prediction errors are computed not in separate units, but locally in dendritic compartments. We then discuss the correspondence of this model to experimentally observed connectivity patterns, plasticity, and dynamics in cortex.
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Affiliation(s)
- Fabian A Mikulasch
- Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany.
| | - Lucas Rudelt
- Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany
| | - Michael Wibral
- Göttingen Campus Institute for Dynamics of Biological Networks, Georg-August University, Göttingen, Germany
| | - Viola Priesemann
- Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany; Bernstein Center for Computational Neuroscience (BCCN), Göttingen, Germany; Department of Physics, Georg-August University, Göttingen, Germany
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13
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Gattoni G, Andrews TGR, Benito-Gutiérrez È. Restricted Proliferation During Neurogenesis Contributes to Regionalisation of the Amphioxus Nervous System. Front Neurosci 2022; 16:812223. [PMID: 35401089 PMCID: PMC8987370 DOI: 10.3389/fnins.2022.812223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 02/17/2022] [Indexed: 11/13/2022] Open
Abstract
The central nervous system of the cephalochordate amphioxus consists of a dorsal neural tube with an anterior brain. Two decades of gene expression analyses in developing amphioxus embryos have shown that, despite apparent morphological simplicity, the amphioxus neural tube is highly regionalised at the molecular level. However, little is known about the morphogenetic mechanisms regulating the spatiotemporal emergence of cell types at distinct sites of the neural axis and how their arrangements contribute to the overall neural architecture. In vertebrates, proliferation is key to provide appropriate cell numbers of specific types to particular areas of the nervous system as development proceeds, but in amphioxus proliferation has never been studied at this level of detail, nor in the specific context of neurogenesis. Here, we describe the dynamics of cell division during the formation of the central nervous system in amphioxus embryos, and identify specific regions of the nervous system that depend on proliferation of neuronal precursors at precise time-points for their maturation. By labelling proliferating cells in vivo at specific time points in development, and inhibiting cell division during neurulation, we demonstrate that localised proliferation in the anterior cerebral vesicle is required to establish the full cell type repertoire of the frontal eye complex and the putative hypothalamic region of the amphioxus brain, while posterior proliferating progenitors, which were found here to derive from the dorsal lip of the blastopore, contribute to elongation of the caudal floor plate. Between these proliferative domains, we find that trunk nervous system differentiation is independent from cell division, in which proliferation decreases during neurulation and resumes at the early larval stage. Taken together, our results highlight the importance of proliferation as a tightly controlled mechanism for shaping and regionalising the amphioxus neural axis during development, by addition of new cells fated to particular types, or by influencing tissue geometry.
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Contribution of animal models toward understanding resting state functional connectivity. Neuroimage 2021; 245:118630. [PMID: 34644593 DOI: 10.1016/j.neuroimage.2021.118630] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/06/2021] [Accepted: 09/29/2021] [Indexed: 12/27/2022] Open
Abstract
Functional connectivity, which reflects the spatial and temporal organization of intrinsic activity throughout the brain, is one of the most studied measures in human neuroimaging research. The noninvasive acquisition of resting state functional magnetic resonance imaging (rs-fMRI) allows the characterization of features designated as functional networks, functional connectivity gradients, and time-varying activity patterns that provide insight into the intrinsic functional organization of the brain and potential alterations related to brain dysfunction. Functional connectivity, hence, captures dimensions of the brain's activity that have enormous potential for both clinical and preclinical research. However, the mechanisms underlying functional connectivity have yet to be fully characterized, hindering interpretation of rs-fMRI studies. As in other branches of neuroscience, the identification of the neurophysiological processes that contribute to functional connectivity largely depends on research conducted on laboratory animals, which provide a platform where specific, multi-dimensional investigations that involve invasive measurements can be carried out. These highly controlled experiments facilitate the interpretation of the temporal correlations observed across the brain. Indeed, information obtained from animal experimentation to date is the basis for our current understanding of the underlying basis for functional brain connectivity. This review presents a compendium of some of the most critical advances in the field based on the efforts made by the animal neuroimaging community.
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Soma S, Suematsu N, Sato AY, Tsunoda K, Bramian A, Reddy A, Takabatake K, Karube F, Fujiyama F, Shimegi S. Acetylcholine from the nucleus basalis magnocellularis facilitates the retrieval of well-established memory. Neurobiol Learn Mem 2021; 183:107484. [PMID: 34175450 DOI: 10.1016/j.nlm.2021.107484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/14/2021] [Accepted: 06/22/2021] [Indexed: 01/31/2023]
Abstract
Retrieval deficit of long-term memory is a cardinal symptom of dementia and has been proposed to associate with abnormalities in the central cholinergic system. Difficulty in the retrieval of memory is experienced by healthy individuals and not limited to patients with neurological disorders that result in forgetfulness. The difficulty of retrieving memories is associated with various factors, such as how often the event was experienced or remembered, but it is unclear how the cholinergic system plays a role in the retrieval of memory formed by a daily routine (accumulated experience). To investigate this point, we trained rats moderately (for a week) or extensively (for a month) to detect a visual cue in a two-alternative forced-choice task. First, we confirmed the well-established memory in the extensively trained group was more resistant to the retrieval problem than recently acquired memory in the moderately trained group. Next, we tested the effect of a cholinesterase inhibitor, donepezil, on the retrieval of memory after a long no-task period in extensively trained rats. Pre-administration of donepezil improved performance and reduced the latency of task initiation compared to the saline-treated group. Finally, we lesioned cholinergic neurons of the nucleus basalis magnocellularis (NBM), which project to the entire neocortex, by injecting the cholinergic toxin 192 IgG-saporin. NBM-lesioned rats showed severely impaired task initiation and performance. These abilities recovered as the trials progressed, though they never reached the level observed in rats with intact NBM. These results suggest that acetylcholine released from the NBM contributes to the retrieval of well-established memory developed by a daily routine.
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Affiliation(s)
- Shogo Soma
- Graduate School of Medicine, Osaka University, Osaka 560-0043, Japan; Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92697, USA; Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Naofumi Suematsu
- Graduate School of Medicine, Osaka University, Osaka 560-0043, Japan; Center for Sciences Towards Symbiosis Among Human, Machine and Data, Kyoto Sangyo University, Kyoto 603-8555, Japan
| | - Akinori Y Sato
- Graduate School of Medicine, Osaka University, Osaka 560-0043, Japan; Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Keisuke Tsunoda
- Graduate School of Medicine, Osaka University, Osaka 560-0043, Japan
| | - Allen Bramian
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92697, USA
| | - Anish Reddy
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92697, USA
| | - Koki Takabatake
- College of Arts & Sciences, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Fuyuki Karube
- Graduate School of Brain Science, Doshisha University, Kyoto 619-0225, Japan; Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan
| | - Fumino Fujiyama
- Graduate School of Brain Science, Doshisha University, Kyoto 619-0225, Japan; Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan
| | - Satoshi Shimegi
- Graduate School of Medicine, Osaka University, Osaka 560-0043, Japan; Center for Education in Liberal Arts and Sciences, Osaka University, Toyonaka, Osaka 560-0043, Japan.
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Shuster SA, Wagner MJ, Pan-Doh N, Ren J, Grutzner SM, Beier KT, Kim TH, Schnitzer MJ, Luo L. The relationship between birth timing, circuit wiring, and physiological response properties of cerebellar granule cells. Proc Natl Acad Sci U S A 2021; 118:e2101826118. [PMID: 34088841 PMCID: PMC8201928 DOI: 10.1073/pnas.2101826118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cerebellar granule cells (GrCs) are usually regarded as a uniform cell type that collectively expands the coding space of the cerebellum by integrating diverse combinations of mossy fiber inputs. Accordingly, stable molecularly or physiologically defined GrC subtypes within a single cerebellar region have not been reported. The only known cellular property that distinguishes otherwise homogeneous GrCs is the correspondence between GrC birth timing and the depth of the molecular layer to which their axons project. To determine the role birth timing plays in GrC wiring and function, we developed genetic strategies to access early- and late-born GrCs. We initiated retrograde monosynaptic rabies virus tracing from control (birth timing unrestricted), early-born, and late-born GrCs, revealing the different patterns of mossy fiber input to GrCs in vermis lobule 6 and simplex, as well as to early- and late-born GrCs of vermis lobule 6: sensory and motor nuclei provide more input to early-born GrCs, while basal pontine and cerebellar nuclei provide more input to late-born GrCs. In vivo multidepth two-photon Ca2+ imaging of axons of early- and late-born GrCs revealed representations of diverse task variables and stimuli by both populations, with modest differences in the proportions encoding movement, reward anticipation, and reward consumption. Our results suggest neither organized parallel processing nor completely random organization of mossy fiber→GrC circuitry but instead a moderate influence of birth timing on GrC wiring and encoding. Our imaging data also provide evidence that GrCs can represent generalized responses to aversive stimuli, in addition to recently described reward representations.
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Affiliation(s)
- S Andrew Shuster
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
- Neurosciences Graduate Program, Stanford University, Stanford, CA 94305
| | - Mark J Wagner
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Nathan Pan-Doh
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Jing Ren
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
- Medical Research Council Laboratory of Molecular Biology, Cambridge University, Cambridge CB2 0QH, United Kingdom
| | - Sophie M Grutzner
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Kevin T Beier
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697
| | - Tony Hyun Kim
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
- Department of Applied Physics, Stanford University, Stanford, CA 94305
| | - Mark J Schnitzer
- HHMI, Stanford University, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
- Department of Applied Physics, Stanford University, Stanford, CA 94305
| | - Liqun Luo
- HHMI, Stanford University, Stanford, CA 94305;
- Department of Biology, Stanford University, Stanford, CA 94305
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Jiang S, Zhu Y, Chen Z, Huang Z, Liu B, Xu Y, Li Z, Lin Z, Li M. S100A14 inhibits cell growth and epithelial-mesenchymal transition (EMT) in prostate cancer through FAT1-mediated Hippo signaling pathway. Hum Cell 2021; 34:1215-1226. [PMID: 33890248 DOI: 10.1007/s13577-021-00538-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 04/16/2021] [Indexed: 11/30/2022]
Abstract
Prostate cancer (PCA) is an epithelial malignant tumor occurring in the prostate gland. It is the second most common male cancer in the world and one of the top five cancer deaths in men. To combat this disease, it is needed to identify important tumor suppressor genes and elucidate the molecular mechanisms. S100 calcium-binding protein A14 (S100A14), a member of the S100 family, is located on chromosome 1q21.3 and contains an EF-hand motif that binds calcium. S100A14 is involved in a variety of tumor biological processes in several types of cancers. Its expression level and related biological functions are tissue or tumor specific. However, its possible effects on prostate cancer are still unclear. Herein, we found the low expression of S100A14 in human prostate cancer tissues and cell lines. S100A14 suppressed the proliferation of prostate cancer cells and promoted cell apoptosis. Additionally, S100A14 suppressed the motility and EMT processes of prostate cancer cells. We further found S100A14 promoted the expression of FAT1 and activated the Hippo pathway, which, therefore, suppressed the prostate cancer progression. The in vivo assays confirmed that S100A14 suppressed tumor growth of prostate cancer cells through FAT1-mediated Hippo pathway in mice. In conclusion, we clarified the mechanism underlying S100A14 suppressing prostate cancer progression and, therefore, we thought S100A14 could serve as a tumor suppressor protein.
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Affiliation(s)
- Shaoqin Jiang
- Department of Urology, Fujian Medical University Union Hospital, No. 29, Xinquan Road, Gulou District, Fuzhou, 350001, Fujian, China
| | - Yaru Zhu
- Intensive Care Unit, Fujian Provincial Governmental Hospital, Fuzhou, 350001, Fujian, China
| | - Zhenlin Chen
- Department of Urology, Fujian Medical University Union Hospital, No. 29, Xinquan Road, Gulou District, Fuzhou, 350001, Fujian, China
| | - Zhangcheng Huang
- Department of Urology, Fujian Medical University Union Hospital, No. 29, Xinquan Road, Gulou District, Fuzhou, 350001, Fujian, China
| | - Bingqiao Liu
- Department of Urology, Fujian Medical University Union Hospital, No. 29, Xinquan Road, Gulou District, Fuzhou, 350001, Fujian, China
| | - Yue Xu
- Department of Urology, Fujian Medical University Union Hospital, No. 29, Xinquan Road, Gulou District, Fuzhou, 350001, Fujian, China
| | - Zhihao Li
- Department of Urology, Fujian Medical University Union Hospital, No. 29, Xinquan Road, Gulou District, Fuzhou, 350001, Fujian, China
| | - Zequn Lin
- Department of Urology, Fujian Medical University Union Hospital, No. 29, Xinquan Road, Gulou District, Fuzhou, 350001, Fujian, China
| | - Mengqiang Li
- Department of Urology, Fujian Medical University Union Hospital, No. 29, Xinquan Road, Gulou District, Fuzhou, 350001, Fujian, China.
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Schuman B, Dellal S, Prönneke A, Machold R, Rudy B. Neocortical Layer 1: An Elegant Solution to Top-Down and Bottom-Up Integration. Annu Rev Neurosci 2021; 44:221-252. [PMID: 33730511 DOI: 10.1146/annurev-neuro-100520-012117] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many of our daily activities, such as riding a bike to work or reading a book in a noisy cafe, and highly skilled activities, such as a professional playing a tennis match or a violin concerto, depend upon the ability of the brain to quickly make moment-to-moment adjustments to our behavior in response to the results of our actions. Particularly, they depend upon the ability of the neocortex to integrate the information provided by the sensory organs (bottom-up information) with internally generated signals such as expectations or attentional signals (top-down information). This integration occurs in pyramidal cells (PCs) and their long apical dendrite, which branches extensively into a dendritic tuft in layer 1 (L1). The outermost layer of the neocortex, L1 is highly conserved across cortical areas and species. Importantly, L1 is the predominant input layer for top-down information, relayed by a rich, dense mesh of long-range projections that provide signals to the tuft branches of the PCs. Here, we discuss recent progress in our understanding of the composition of L1 and review evidence that L1 processing contributes to functions such as sensory perception, cross-modal integration, controlling states of consciousness, attention, and learning.
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Affiliation(s)
- Benjamin Schuman
- Neuroscience Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA;
| | - Shlomo Dellal
- Neuroscience Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA;
| | - Alvar Prönneke
- Neuroscience Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA;
| | - Robert Machold
- Neuroscience Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA;
| | - Bernardo Rudy
- Neuroscience Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA; .,Department of Anesthesiology, Perioperative Care and Pain Medicine, New York University School of Medicine, New York, NY 10016, USA
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An Atoh1 CRE Knock-In Mouse Labels Motor Neurons Involved in Fine Motor Control. eNeuro 2021; 8:ENEURO.0221-20.2021. [PMID: 33468540 PMCID: PMC7901153 DOI: 10.1523/eneuro.0221-20.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 01/05/2021] [Accepted: 01/08/2021] [Indexed: 11/21/2022] Open
Abstract
Motor neurons (MNs) innervating the digit muscles of the intrinsic hand (IH) and intrinsic foot (IF) control fine motor movements. The ability to reproducibly label specifically IH and IF MNs in mice would be a beneficial tool for studies focused on fine motor control. To this end, we find that a CRE knock-in mouse line of Atoh1, a developmentally expressed basic helix-loop-helix (bHLH) transcription factor, reliably expresses CRE-dependent reporter genes in ∼60% of the IH and IF MNs. We determine that CRE-dependent expression in IH and IF MNs is ectopic because an Atoh1 mouse line driving FLPo recombinase does not label these MNs although other Atoh1-lineage neurons in the intermediate spinal cord are reliably identified. Furthermore, the CRE-dependent reporter expression is enriched in the IH and IF MN pools with much sparser labeling of other limb-innervating MN pools such as the tibialis anterior (TA), gastrocnemius (GS), quadricep (Q), and adductor (Ad). Lastly, we find that ectopic reporter expression begins postnatally and labels a mixture of α and γ-MNs. Altogether, the Atoh1 CRE knock-in mouse strain might be a useful tool to explore the function and connectivity of MNs involved in fine motor control when combined with other genetic or viral strategies that can restrict labeling specifically to the IH and IF MNs. Accordingly, we provide an example of sparse labeling of IH and IF MNs using an intersectional genetic approach.
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