Hindlimb muscle representations in mouse motor cortex defined by viral tracing
IntroductionDescending pathways from the cortex to the spinal cord are involved in the control of natural movement. Although mice are widely used to study the neurobiology of movement and as models of neurodegenerative disease, an understanding of motor cortical organization is lacking, particularly...
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Frontiers Media S.A.
2023-05-01
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| Series: | Frontiers in Neuroanatomy |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fnana.2023.965318/full |
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| author | Lauren Maurer Maia Brown Tamandeep Saggi Alexia Cardiges Christi L. Kolarcik Christi L. Kolarcik Christi L. Kolarcik Christi L. Kolarcik Christi L. Kolarcik |
| author_facet | Lauren Maurer Maia Brown Tamandeep Saggi Alexia Cardiges Christi L. Kolarcik Christi L. Kolarcik Christi L. Kolarcik Christi L. Kolarcik Christi L. Kolarcik |
| author_sort | Lauren Maurer |
| collection | DOAJ |
| description | IntroductionDescending pathways from the cortex to the spinal cord are involved in the control of natural movement. Although mice are widely used to study the neurobiology of movement and as models of neurodegenerative disease, an understanding of motor cortical organization is lacking, particularly for hindlimb muscles.MethodsIn this study, we used the retrograde transneuronal transport of rabies virus to compare the organization of descending cortical projections to fast- and slow-twitch hindlimb muscles surrounding the ankle joint in mice.ResultsAlthough the initial stage of virus transport from the soleus muscle (predominantly slow-twitch) appeared to be more rapid than that associated with the tibialis anterior muscle (predominantly fast-twitch), the rate of further transport of virus to cortical projection neurons in layer V was equivalent for the two injected muscles. After appropriate survival times, dense concentrations of layer V projection neurons were identified in three cortical areas: the primary motor cortex (M1), secondary motor cortex (M2), and primary somatosensory cortex (S1).DiscussionThe origin of the cortical projections to each of the two injected muscles overlapped almost entirely within these cortical areas. This organization suggests that cortical projection neurons maintain a high degree of specificity; that is, even when cortical projection neurons are closely located, each neuron could have a distinct functional role (controlling fast- versus slow-twitch and/or extensor versus flexor muscles). Our results represent an important addition to the understanding of the mouse motor system and lay the foundation for future studies investigating the mechanisms underlying motor system dysfunction and degeneration in diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy. |
| first_indexed | 2024-03-13T09:39:35Z |
| format | Article |
| id | doaj.art-77fb4eb4ffc0483cb11fbd81bd6b49ad |
| institution | Directory Open Access Journal |
| issn | 1662-5129 |
| language | English |
| last_indexed | 2024-03-13T09:39:35Z |
| publishDate | 2023-05-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Neuroanatomy |
| spelling | doaj.art-77fb4eb4ffc0483cb11fbd81bd6b49ad2023-05-25T04:38:31ZengFrontiers Media S.A.Frontiers in Neuroanatomy1662-51292023-05-011710.3389/fnana.2023.965318965318Hindlimb muscle representations in mouse motor cortex defined by viral tracingLauren Maurer0Maia Brown1Tamandeep Saggi2Alexia Cardiges3Christi L. Kolarcik4Christi L. Kolarcik5Christi L. Kolarcik6Christi L. Kolarcik7Christi L. Kolarcik8Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United StatesDepartment of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United StatesDepartment of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United StatesDepartment of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United StatesDepartment of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United StatesDepartment of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United StatesLiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, United StatesMcGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United StatesCenter for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, United StatesIntroductionDescending pathways from the cortex to the spinal cord are involved in the control of natural movement. Although mice are widely used to study the neurobiology of movement and as models of neurodegenerative disease, an understanding of motor cortical organization is lacking, particularly for hindlimb muscles.MethodsIn this study, we used the retrograde transneuronal transport of rabies virus to compare the organization of descending cortical projections to fast- and slow-twitch hindlimb muscles surrounding the ankle joint in mice.ResultsAlthough the initial stage of virus transport from the soleus muscle (predominantly slow-twitch) appeared to be more rapid than that associated with the tibialis anterior muscle (predominantly fast-twitch), the rate of further transport of virus to cortical projection neurons in layer V was equivalent for the two injected muscles. After appropriate survival times, dense concentrations of layer V projection neurons were identified in three cortical areas: the primary motor cortex (M1), secondary motor cortex (M2), and primary somatosensory cortex (S1).DiscussionThe origin of the cortical projections to each of the two injected muscles overlapped almost entirely within these cortical areas. This organization suggests that cortical projection neurons maintain a high degree of specificity; that is, even when cortical projection neurons are closely located, each neuron could have a distinct functional role (controlling fast- versus slow-twitch and/or extensor versus flexor muscles). Our results represent an important addition to the understanding of the mouse motor system and lay the foundation for future studies investigating the mechanisms underlying motor system dysfunction and degeneration in diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy.https://www.frontiersin.org/articles/10.3389/fnana.2023.965318/fullcortical representationsmotor cortexhindlimb musclemotor controlneural circuit |
| spellingShingle | Lauren Maurer Maia Brown Tamandeep Saggi Alexia Cardiges Christi L. Kolarcik Christi L. Kolarcik Christi L. Kolarcik Christi L. Kolarcik Christi L. Kolarcik Hindlimb muscle representations in mouse motor cortex defined by viral tracing Frontiers in Neuroanatomy cortical representations motor cortex hindlimb muscle motor control neural circuit |
| title | Hindlimb muscle representations in mouse motor cortex defined by viral tracing |
| title_full | Hindlimb muscle representations in mouse motor cortex defined by viral tracing |
| title_fullStr | Hindlimb muscle representations in mouse motor cortex defined by viral tracing |
| title_full_unstemmed | Hindlimb muscle representations in mouse motor cortex defined by viral tracing |
| title_short | Hindlimb muscle representations in mouse motor cortex defined by viral tracing |
| title_sort | hindlimb muscle representations in mouse motor cortex defined by viral tracing |
| topic | cortical representations motor cortex hindlimb muscle motor control neural circuit |
| url | https://www.frontiersin.org/articles/10.3389/fnana.2023.965318/full |
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