China
Africa
Explore chapters and articles related to this topic
Assessing Paediatric Development in Psychiatry
Published in Cathy Laver-Bradbury, Margaret J.J. Thompson, Christopher Gale, Christine M. Hooper, Child and Adolescent Mental Health, 2021
The basal ganglia nuclei are essential partners of the motor system. As a unit they are responsible for preventing unwanted movements from being instigated, along with allowing the current constellation of motor signals, already occurring between the cortex and the spine, to continue to be relayed, unimpeded. The indirect pathway is responsible for the former, the direct pathway, the latter.
Biochemical Contributors to Exercise Fatigue
Published in Peter M. Tiidus, Rebecca E. K. MacPherson, Paul J. LeBlanc, Andrea R. Josse, The Routledge Handbook on Biochemistry of Exercise, 2020
Arthur J. Cheng, Maja Schlittler, Håkan Westerblad
Muscle contraction is linked by a series of events, and fatigue can potentially be attributed to failure at any of the cellular sites involved in the activation and contraction of the muscle fibres (Figure 5.4). The activation of skeletal muscle contraction starts at the central nervous system, thereby activating α-motor neurons, and action potentials propagate along the axons of these neurons out to the muscle fibres. The smallest functional unit of the central motor system, the motor unit, consists of one α-motor neuron and the muscle fibres it activates. The number of muscle fibres in a motor unit varies from muscle to muscle. For instance, in the hand an α-motor neuron generally activates fewer than 100 muscle fibres, whereas for the lower leg a single motor unit may contain up to 1,000 muscle fibres (12). Generally, the larger the number of muscle fibres in a motor unit, the less precise the associated movements.
Control of Movement and Posture
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The control and maintenance of posture is another truly amazing feat of the motor system. Not only can we stand upright, but we can also control our posture, that is, the relative position of our body parts, during movement. Witness a waiter weaving swiftly between tables in a crowded restaurant while balancing with one hand a tray full of food and drinks. Or consider how one may regain one’s balance when stumbling.
A rare cause of stroke in young children: minor head trauma associated with mineralising lenticulostriate angiopathy in three patients
Published in Paediatrics and International Child Health, 2022
Kiruthiga Sugumar, Aakash Chandran Chidambaram, Bobbity Deepthi, Sriram Krishnamurthy, C. G. Delhikumar
Mineralising angiopathy presenting as basal ganglia stroke after minor head trauma is limited to case series and reports [1,2,8–10]. The relationship between minor head trauma and mineralising angiopathy presenting as acute basal ganglia stroke was first described in 2013 as a clinico-radiological syndrome in 22 children aged 6–24 months diagnosed with hemiparesis as the presenting complaint [1]. In the three cases in the present report, the time lag between the trauma and onset of hemiparesis ranged from 10 min to 4 h, comparable with that observed in other reports [2,9]. Hemidystonia has been reported frequently in this condition [1,3,8]. This is an involuntary, sustained posturing of the unilateral arm, leg and face owing to aberrant re-organisation of the motor system after a static lesion.
Surround inhibition in patients with juvenile myoclonic epilepsy
Published in Neurological Research, 2021
Bengi Gul Turk, Naz Yeni, Aysegul Gunduz, Ceren Alis, Meral Kiziltan
Certain physiological steps in the generation of SI are still unknown. In motor system, basal ganglia were suggested to be the origin of inhibitory output via thalamus to the cortex in order to choose the most accurate voluntary movement [18,20]. Deficient SI in the motor system in Parkinson’s disease also supports this hypothesis [21]. Tinazzi and colleagues showed a defect of somatosensory SI in dystonic patients and attributed it to a reduction in cortical inhibitory function in dystonia [3]. Actually, this is a subject of discussion whether there is a shared mechanism that disturbs SI in dystonia and bradykinesia of Parkinson’s disease. Similar to motor system, SI in the somatosensory system may enable to perform the desired movements by inhibiting the undesired ones [18]. The SI in the somatosensory system may be associated with the somatosensory and motor cortices, and with cuneate nucleus, locus ceruleus, thalamus and brainstem [22]. Tinazzi and colleagues [3] demonstrated the presence of SI at the spinal, brainstem and cortical levels of the lemniscal pathway.
The role of the precuneus and posterior cingulate cortex in the neural routes to action
Published in Computer Assisted Surgery, 2019
Zijian Wang, Liu Fei, Yaoru Sun, Jie Li, Fang Wang, Zheng Lu
After the activations of all contrast images were obtained, firstly images were analyzed contrastively for each task, and we also checked whether the activation results conformed to those reported in previous work. Then a direct comparison between PA-PN and NA-NR was conducted to locate the locations of significant different activities, and it was calculated by T contrasts (p < .0005 at voxel level) and cluster-level family-wise error (FWE) correction (p < .05, corrected). The next step was to identify the cortical regions activated by action generation tasks and examine the regions activated by PA-PN and NA-NR. Finally, the activations in the whole brain were compared, and at the same time, the similarities and differences in the cortical regions, especially the motor system were analyzed.