scholarly journals TRK-fused Gene Protein Localization Is Prominent in Serotonergic and Noradrenergic Cell Groups, and Some Lower Motor Neurons in the Corticospinal Tract of the Rat Brainstem

2018 ◽  
Vol 51 (3) ◽  
pp. 111-118
Author(s):  
Shigeko Takeuchi ◽  
Ikuo Tooyama
Author(s):  
Abderrazek Zeraii ◽  
Amine Ben Slama ◽  
Lazhar Rmili ◽  
Cyrine Drissi ◽  
Mokhtar Mars ◽  
...  

Stroke remains the leading source of long-term disability. As the only direct descending motor pathway, the corticospinal tract (CST) is the primary pathway to innervate spinal motor neurons and one of the most well studied tracts in human neuroanatomy. Its clinical significance can be demonstrated in many distinguished traumatic situations and diseases such as stroke. Along‐tract statistics analysis enables the extraction of quantitative diffusion metrics along specific white matter fiber tracts. Besides quantitative metrics derived from classical diffusion tensor imaging (DTI), such as fractional anisotropy and diffusivities. In this study, we extracted DTI derived quantitative microstructural diffusion metrics along the CST tract in patients with moderate to severe subacute stroke. Respectively DTI metric of individual patient's fiber tract was then plotted. This approach may be useful for future studies that may compare in two different time (acute and chronic). The contribution of this work presents a totally computerized method of DTI image recognition based on conventional neural network (CNN) in order to supply quantitative appraisal of clinical characteristics. The obtained results have achieved an important classification (Accuracy=94.12%) when applying the CNN. The proposed methodology enables us to assess the classification of the used DTI images database within a reduced processing time. Experimental results prove the success of the proposed rating system for a suitable analysis of microstructural diffusion when compared to previous work.


Author(s):  
Manuel Víctor López-González ◽  
Marta González-García ◽  
Marc Stefan Dawid-Milner

2020 ◽  
Vol 21 (20) ◽  
pp. 7485
Author(s):  
Ken Muramatsu

Although motor deficits in humans with diabetic neuropathy have been extensively researched, its effect on the motor system is thought to be lesser than that on the sensory system. Therefore, motor deficits are considered to be only due to sensory and muscle impairment. However, recent clinical and experimental studies have revealed that the brain and spinal cord, which are involved in the motor control of voluntary movement, are also affected by diabetes. This review focuses on the most important systems for voluntary motor control, mainly the cortico-muscular pathways, such as corticospinal tract and spinal motor neuron abnormalities. Specifically, axonal damage characterized by the proximodistal phenotype occurs in the corticospinal tract and motor neurons with long axons, and the transmission of motor commands from the brain to the muscles is impaired. These findings provide a new perspective to explain motor deficits in humans with diabetes. Finally, pharmacological and non-pharmacological treatment strategies for these disorders are presented.


2006 ◽  
Vol 95 (2) ◽  
pp. 979-994 ◽  
Author(s):  
Chris R. S. Kaneko

The paramedian pontine reticular formation contains the premotoneuronal cell groups that constitute the saccadic burst generator and control saccadic eye movements. Despite years of study and numerous investigations, the rostral portion of this area has received comparatively little attention, particularly the cell type known as long-lead burst neurons (LLBNs). Several hypotheses about the functional role of LLBNs in saccade generation have been proposed, although there is little information with which to assess them. To address this issue, I mapped and recorded LLBNs in the rostral pons to measure their discharge characteristics and correlate those characteristics with the metrics of the concurrent saccades. On the basis of their discharge and location, I identified three types of LLBNs in the rostral pons: excitatory (eLLBN), dorsal (dLLBN), and nucleus reticularis tegmenti pontis (nrtp) LLBNs. The eLLBNs, encountered throughout the pons, discharge for ipsilateral saccades in proportion to saccade amplitude, velocity, and duration. The dLLBNs, found at the pontomesencephalic junction, discharge maximally for ipsilateral saccades of a particular amplitude, usually <10°, and are not associated with a particular anatomical nucleus. The nrtp LLBNs, previously described as vector LLBNs, discharge for saccades of a particular direction and sometimes a particular amplitude. The discharge of the eLLBNs suggests they drive motor neurons. The anatomical projections of the nrtp LLBNs suggest that their involvement in saccade production is less direct. The discharge of dLLBNs is consistent with a role in providing the “trigger” signal that initiates saccades.


Author(s):  
Martin R. Turner

Motor neuron disease (MND) is characterized by progressive muscular weakness due to simultaneous degeneration of lower and upper motor neurons (L/UMNs). Involvement of LMNs, arising from the anterior horns of the spinal cord and brainstem, leads to secondary wasting as a result of muscle denervation. Involvement of the UMNs of the motor cortex and corticospinal tract results in spasticity. In ~85% of cases, there is clear clinical involvement of both, and the condition is termed ‘amyotrophic lateral sclerosis’ (ALS; a term often used synonymously with MND). In ~13% of cases, there may be only LMN signs apparent, in which case the condition is termed ‘progressive muscular atrophy’, although such cases have a natural history that is to largely identical to that of ALS. In a very small group of patients (~2%), there are only UMN signs for at least the first 4 years, in which case the condition is termed ‘primary lateral sclerosis’; such cases have a uniformly slower progression. There is clinical, neuropathological, and genetic overlap between MND and some forms of frontotemporal dementia.


2007 ◽  
Vol 103 (6) ◽  
pp. 2095-2104 ◽  
Author(s):  
Christopher G. Wilson ◽  
Shamima Akhter ◽  
Catherine A. Mayer ◽  
Prabha Kc ◽  
Kannan V. Balan ◽  
...  

Brain stem noradrenergic cell groups mediating autonomic responses to stress project to airway-related vagal preganglionic neurons (AVPNs). In ferrets, their activation produces withdrawal of cholinergic outflow to the airways via release of norepinephrine and activation of α2A-adrenergic receptors (α2A-AR) expressed by AVPNs. In these studies, we examined the effects of allergen exposure of the airway (AE) with ovalbumin on noradrenergic transmission regulating the activity of AVPNs and, consequently, airway smooth muscle tone. Experiments were performed in vehicle control (Con) and AE ferrets. Microperfusion of an α2A-AR agonist (guanabenz) in close proximity to AVPNs elicited more pronounced effects in Con than AE ferrets, including a decrease in unit activity and reflexly evoked responses of putative AVPN neurons with a corresponding decrease in cholinergic outflow to the airways. Although no differences were found in the extent of noradrenergic innervation of the AVPNs, RT-PCR and Western blot studies demonstrated that AE and repeated exposure to antigen significantly reduced expression of α2A-ARs at message and protein levels. These findings indicate that, in an animal model of allergic asthma, sensitization and repeated challenges with a specific allergen diminish central inhibitory noradrenergic modulation of AVPNs, possibly via downregulation of α2A-AR expression by these neurons.


2012 ◽  
Vol 45 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Shigeko Takeuchi ◽  
Chiaki Masuda ◽  
Hisae Maebayashi ◽  
Ikuo Tooyama

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