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Neuromuscular Physiology
Published in Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan, Strength and Conditioning in Sports, 2023
Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan
Simplistically, voluntary movement is initiated by the primary motor cortex (MC) with input from the premotor cortex (PMC) and the supplementary motor area (SMA) (109). Information from cortical and subcortical nuclei is relayed by the PMC to the primary MC. For coordinated movement to occur sensory information transfer from subcortical areas to the MC is necessary. The PMC functions in the preparation for voluntary movements and also in postural control, visual guidance of movement, and rapid corrections during movement in response to sensory cues (109, 136). The function of the SMA include postural stabilization, bilateral coordination, control of movements that are internally generated rather than triggered by sensory events, and the control of movement sequencing (109, 117, 169, 199).
Amyotrophic Lateral Sclerosis
Published in Charles Theisler, Adjuvant Medical Care, 2023
The disorder results from a loss of motor neurons in the motor cortex (upper motor neurons) and in the brain stem and central spinal cord (lower motor neurons).1 ALS usually strikes people between the ages of 40 and 70 and occurs more often in male patients than in female patients.
Examination of a Child with Cerebral Palsy
Published in Nirmal Raj Gopinathan, Clinical Orthopedic Examination of a Child, 2021
The newborn possesses some infantile reflex mechanisms that usually disappear by 3–6 months of age when the motor cortex matures. In CP, these reflexes might be retained and aid in diagnosing the disorder (Table 13.3).
Transcranial Direct Current Stimulation of Motor Cortex Enhances Spike Performances of Professional Female Volleyball Players
Published in Journal of Motor Behavior, 2023
Seung-Bo Park, Doug Hyun Han, Junggi Hong, Jea-Woog Lee
In another aspect, although electrical stimulation was applied to the specific cortical area of M1 induced by tDCS in the present study, it might have affected adjacent areas, resulting in a somewhat more widespread area of target stimulation. This means that the premotor cortex, complex system of interconnected frontal lobe areas anterior to the primary motor cortex, s mainly responsible for motor functions. The upper motor neurons in the premotor cortex regulates motor behavior via extensive reciprocal connections with the primary motor cortex and axons projecting through the corticobulbar and corticospinal pathways that affect local circuit and lower motor neurons of the spinal cord and brainstem (Purves et al., 2001). In particular, the left dorsal premotor cortex activity is associated with complex motor coordination performance, meaning that tDCS has potential to improve visuomotor coordination (Pavlova et al., 2014). According to Tzvi et al. (2022), the cerebellum plays an essential role in the process of visuomotor adaptation. They noted that interaction with cortical structures, especially the premotor cortex, contributed mainly to this process. The cerebellum plays a central role in coordinating voluntary movements and motor skills including balance, coordination, and posture (Manto et al., 2012). These relationships suggest that activation of the premotor cortex and its interactions with the cerebellum could enhance the process of motor coordination by tDCS (Kwon et al., 2015; Tzvi et al., 2022).
Alterations in motor functional connectivity in Neonatal Hypoxic Ischemic Encephalopathy
Published in Brain Injury, 2022
Li Jiang, Dina El-Metwally, Chandler Sours Rhodes, Jiachen Zhuo, Ranyah Almardawi, Alexandre E Medina, Li Wang, Rao P. Gullapalli, Prashant Raghavan
The presence, at birth, of primary sensorimotor, auditory, visual and proto-default mode and attention networks in both term and preterm infants using rs-fMRI has previously been reported (26,27). These networks consist of localized interhemispheric connections between homotopic counterparts. Using a seed based method, Smyser et al demonstrated that interhemispheric connections develop earlier between homologous brain areas that are anatomically closer together, such as the cingulate and motor cortices, than those that are farther apart, such as the temporal cortex (28). Furthermore, term infants are more likely to demonstrate connectivity between homologous face regions of the motor cortex when compared to preterm infants. In addition, animal models have revealed that HIE injury is a highly organized, system-preferential, topographic encephalopathy, often targeting regions crucial for sensorimotor integration and movement control (29). Our results reflecting reductions in inter-hemispheric rs-FC between primary motor cortical areas and also between primary motor cortical areas and the cerebellum may reflect this phenomenon. Importantly, such changes were observed largely in the absence of structural changes in the brain, suggesting the potential greater sensitivity of rs-fMRI to detect subtle disruptions of functional communications within these neonates.
Substrates of speech treatment-induced neuroplasticity in adults and children with motor speech disorders: A systematic scoping review of neuroimaging evidence
Published in International Journal of Speech-Language Pathology, 2021
Brooke-Mai Whelan, Deborah Theodoros, Katie L. Mcmahon, David Copland, Danielle Aldridge, Jessica Campbell
The LSVT-LOUD® program targets motor and sensory loudness training, whereby the speaker is coached to self-monitor loudness levels and recalibrate when necessary. A specialised role for the right hemisphere has been established in the perception of music and speech sound intensity in healthy subjects (Brancucci, Babiloni, Rossini, & Romani, 2005). Intensive speech treatment in relation to a targeted level of vocal intensity, therefore, appears to enlist the right hemisphere in the refinement of speech sound intensity perception. Reduced activations within the motor speech areas of the primary motor cortex (M1 mouth) following treatment also implies that sensory-motor volume re-training alters neural activity within this speech dedicated area. The normalisation of post-LSVT-LOUD® activations within M1 is supported by evidence of significantly greater fMRI activations in M1 during voiced versus voiceless speech production in normals (Correia, Caballero-Gaudes, Guediche, & Carreiras, 2020). This finding suggests control of the intrinsic muscles of the larynx to be facilitated by M1, and that laryngeal function and neural activity within M1 can be altered, or rather normalised by intensive training.