{"doi":"10.1101/2025.08.12.669858","title":"Circular continuum of alpha motoneuron types","abstract":"Alpha-motoneurons (α-MNs) are traditionally classified into slow (S), fast fatigue-resistant (FR), and fast-fatigable (FF), which exist along a continuum of properties between slow and fast, enabling the generation of graded force and seamless movement. Using combinations of markers, we developed novel immunohistochemistry protocols that enabled co-labeling of six major and transitional α-MN types throughout the mouse lumbar spinal cord with unprecedented detail. Intriguingly, our protocols labeled for the first time: α-MNs of the fast fatigue intermediate (FI) type; a previously undescribed transitional α-MN subtype (FR/FI); and a novel subtype of α-MNs exhibiting hybrid characteristics of both S and FF types - termed S/FF - which resist ALS degeneration. Electrophysiological recordings confirmed FR/FI and S/FF subtypes, both exhibiting mixed traits. The discovery of S/FF subtype reveals that α-MNs exist along a circular continuum between slow and fast types, challenging the traditional linear model and reshaping our understanding of their role in motor control. New & Noteworthy: This study introduces a novel immunohistochemistry protocol to co-label six distinct types of adult spinal cord motor neurons. This technical innovation led to a conceptual paradigm shift, revealing a circular continuum of motor neuron subtypes rather than a linear one. This new framework provides unprecedented precision for studying their varying susceptibility to degeneration in diseases like ALS, with broad implications for understanding motor control in health and disease.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2025,"id":556667,"datarank":0.16479184330021646,"base_score":1.0986122886681096,"endowment":1.0986122886681096,"self_citation_contribution":0.16479184330021646,"citation_network_contribution":0.0,"self_endowment_contribution":0.16479184330021646,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":2,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9474,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1456733,"name":"Lee Wintermute","orcid":null,"position":1,"is_corresponding":false},{"id":1456734,"name":"Maggie Armitage","orcid":null,"position":2,"is_corresponding":false},{"id":446644,"name":"Shelby Ward","orcid":null,"position":3,"is_corresponding":false},{"id":1456735,"name":"Ibrahim Abdul Halim","orcid":null,"position":4,"is_corresponding":false},{"id":1456360,"name":"Mohamed H. Mousa","orcid":"0000-0002-6584-3792","position":5,"is_corresponding":false},{"id":1456736,"name":"K Pereira Gerber","orcid":null,"position":6,"is_corresponding":false},{"id":768086,"name":"Sherif M. Elbasiouny","orcid":"0000-0002-6227-3894","position":7,"is_corresponding":false},{"id":1111347,"name":"Teresa L. Garrett","orcid":null,"position":0,"is_corresponding":true}],"reference_count":31,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-19T02:55:13.130091Z","pmid":"40832332","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}