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Leg Pain
Published in Benjamin Apichai, Chinese Medicine for Lower Body Pain, 2021
The pyramidal tracts are comprised of the corticospinal tract and the corticobulbar tract. Because their nerve fibers are mainly derived from pyramidal cells in the cerebral cortex, they are called pyramidal tracts. After leaving the cerebral cortex, the pyramidal tract moves through the inner capsule and the cerebra peduncle to the medulla. Most of the nerve fibers cross over at the caudal end of the medulla to the contralateral side of the body, which is referred to as decussation of the pyramids (Rea 2015), enter the spinal cord (corticospinal) or the brain stem (corticobulbar), and control the motor function of the body.
Cranial Neuropathies I, V, and VII–XII
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
A supranuclear lesion affecting the corticobulbar tract results in contralateral weakness of the lower facial muscles.31 The most severely affected muscles are the ones surrounding the mouth with occasional involvement of the orbicularis oculi. The muscles of the forehead are spared and there is no hyperacusis, or dysgeusia.
The nervous system
Published in Peter Kopelman, Dame Jane Dacre, Handbook of Clinical Skills, 2019
Peter Kopelman, Dame Jane Dacre
Bulbar and pseudobulbar palsy Unilateral damage of the pathways from the cortex to the lower cranial nerve nuclei (the corticobulbar tracts) may produce transient weakness of the many muscles supplied by these nerves. This results in temporary unilateral weakness of the muscles of the jaw, lower parts of the face, palate, pharynx, larynx, neck and tongue. There is a rapid recovery even after extensive lesions because the corticobulbar tract on the other side can generally take over the function. Bilateral damage (which may follow repeated strokes) results in persistent weakness and spasticity of the muscles supplied by the bulbar nuclei. As a result, there is slurring of speech and dysphagia (difficulty in swallowing), the jaw jerk is abnormally brisk and movements of the tongue are reduced in amplitude. In addition, there is loss of voluntary control of emotional expression and the patient may laugh or cry without apparent provocation.
A potential upper motor neuron measure of bulbar involvement in amyotrophic lateral sclerosis using jaw muscle coherence
Published in Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 2021
Among different jaw muscle pairs, the beta-band coherence for an antagonistic pair (Right masseter × Right digastric) and a homologous pair (Right digastric × Left digastric) revealed the largest decreases in ALS. Given the origin of beta oscillations in the motor cortical network (35), such decreases of beta-band intermuscular coherence can be interpreted as the result of decreased cortical drive to the jaw muscles, due to the degeneration of the corticobulbar tract. Furthermore, the decreases of masseter–digastric coherence and digastric–digastric coherence were observed early in the prodromal stage (Figure 7), suggesting that the cortical drive to these muscles was also affected prodromally. This is consistent with the well-documented precedence of subclinical bulbar changes over clinical symptoms (12,36,37).
Foix-Chavany-Marie syndrome due to unilateral anterior opercular infarction with leukoaraiosis
Published in Baylor University Medical Center Proceedings, 2021
Katherine Rivas, Jie Pan, Angela Chen, Bailey Gutiérrez, Parunyou Julayanont
The current mapping of the divisions of the operculum has demonstrated that stimulation causes motor and language deficits as well as somatosensory and oropharyngeal symptoms.5 The anterior operculum contains the voluntary motor fibers for the 5th, 7th, 9th, 10th, and 12th cranial nerves, which then travel to the cranial nerve nuclei via the corticobulbar tract.1,2 Injury to this area can cause FCMS bilateral voluntary paralysis of facial, masticatory, pharyngeal, laryngeal, and brachial muscles.6–8 Autonomic-voluntary dissociation in FCMS is explained by the presence of alternative pathways for facial emotional expression and automatic movements, hypothesized to be mediated through the inner forebrain and outer longitudinal bundle that connect the amygdala and hypothalamus to the brainstem.1,2
Speech network regional involvement in bulbar ALS: a multimodal structural MRI study
Published in Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 2019
Sanjana Shellikeri, Matthew Myers, Sandra E. Black, Agessandro Abrahao, Lorne Zinman, Yana Yunusova
This study served as a pilot investigating the relationship between bulbar motor dysfunction and neuroanatomy of the SpN regions. We recognize the limitations posed by the small sample size and the cross-sectional design of the study. The study findings need to be confirmed using a larger cohort of ALS patients with longitudinal and simultaneous neuroimaging, motor speech, and detailed language testing. Furthermore, the DTI protocol employed in this study was limited in its number of directions and did not allow tractography analyses. Individual fiber tract tracing may be especially important in smaller, more variable WM pathways such as the corticobulbar tract.