Beta inputs to motor neurons do not directly contribute to volitional force modulation

Zicher, Blanka ; Ibáñez, Jaime ; Farina, Dario

Resumen: Neural oscillatory activity in the beta band (13–30 Hz) is prominent in the brain and it is transmitted partly linearly to the spinal cord and muscles. Multiple views on the functional relevance of beta activity in the motor system have been proposed. Previous simulation work suggested that pools of spinal motoneurons (MNs) receiving a common beta input could demodulate this activity, transforming it into low-frequency neural drive that could alter force production in muscles. This may suggest that common beta inputs to muscles have a direct role in force modulation. Here we report the experimental average levels and ranges of common beta activity in spinal MNs projecting to single muscles and use a computational model of a MN pool to test if the experimentally observed beta levels in MNs can influence force. When beta was modelled as a continuous activity, the amplitude needed to produce non-negligible changes in force corresponded to beta representation in the MN pool that was far above the experimental observations. On the other hand, when beta activity was modelled as short-lived events (i.e. bursts of beta activity separated by intervals without beta oscillations), this activity approximated levels that could cause small changes in force with estimated average common beta inputs to the MNs compatible with the experimental observations. Nonetheless, bursting beta is unlikely to be used for force control due to the temporal sparsity of this activity. It is therefore concluded that beta oscillations are unlikely to contribute to the voluntary modulation of force.

Idioma: Inglés

DOI: 10.1113/JP283398

Año: 2022

Publicado en: JOURNAL OF PHYSIOLOGY-LONDON 601, 15 (2022), 3173-3185
ISSN: 0022-3751

Factor impacto JCR: 5.5 (2022)

Categ. JCR: PHYSIOLOGY rank: 10 / 79 = 0.127 (2022) - Q1 - T1
Categ. JCR: NEUROSCIENCES rank: 59 / 272 = 0.217 (2022) - Q1 - T1

Factor impacto CITESCORE: 9.9 - Biochemistry, Genetics and Molecular Biology (Q1)

Factor impacto SCIMAGO: 1.557 - Sports Science (Q1) - Physiology (Q1)

Financiación: info:eu-repo/grantAgreement/EC/H2020/899626/EU/NIMA: Non-invasive Interface for Movement Augmentation/NIMA

Tipo y forma: Artículo (Versión definitiva)