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Brain Motor Centers and Pathways
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
Feedback loops exist between the cortex and the basal ganglia. One feedback loop is through the direct pathway involving striatal output neurons, which inhibit their target neurons in the GPi. In turn, these inhibit neurons in the ventral lateral nucleus pars oralis (VLo), which is part of the ventral lateral (VL) nucleus of the thalamus. The result is disinhibition of neurons of the VLo, which excites the cortical cells:
Specific Synonyms
Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
Nucleus ventralis intermedius (W&W, p. 958) Ventral lateral nucleus (B&K, p. 187)This is a thalamic nucleus.
Thalamocortical neural responses during hyperthermia: a resting-state functional MRI study
Published in International Journal of Hyperthermia, 2018
Jing Zhang, Shaowen Qian, Qingjun Jiang, Guanzhong Gong, Kai Liu, Bo Li, Yong Yin, Gang Sun
Consistent with previous studies, each cortical region was specifically connected to distinct nuclei within the thalamus (Figure 3). Specifically, thalamic connectivity with the somatosensory and motor/premotor subdivisions was mainly located in the ventral posterior lateral nucleus in both groups. Paired comparison showed increased thalamic connectivity in the ventral lateral nucleus with the cortical somatosensory and motor/premotor areas during hyperthermia. The prefrontal subdivision was robustly connected to medial dorsal nucleus in both groups. Between-group comparison revealed that decreased thalamic connectivity in the bilateral medial dorsal nucleus and left ventral posterior lateral nucleus with the prefrontal ROI was found in HC group. The frontal polar and ACC showed strong connections to ventral medial and lateral nucleus in the hyperthermic condition, whereas to ventral medical nucleus and pulvinar in the normal condition. Paired comparison revealed decreased connectivity of the frontal-polar and ACC with bilateral ventral anterior nucleus and left pulvinar during hyperthermia. The temporal cortex in both conditions showed strong correlation with posterior medial nucleus. But increased correlation with the bilateral pulvinar in the HC condition during the paired comparison. The posterior parietal cortex correlated strongly with lateral posterior nucleus and pulvinar in the HC group, whereas with ventral pulvinar in the NC group. The occipital ROIs showed strong connections to ventral lateral nucleus. But no significant differences were found by posterior parietal cortex and occipital ROIs during group-paired comparisons.
Altered cerebral perfusion and microstructure in advanced Parkinson’s disease and their associations with clinical features
Published in Neurological Research, 2022
Zhaoxi Liu, Yiwei Zhang, Han Wang, Dan Xu, Hui You, Zhentao Zuo, Feng Feng
Dopaminergic neurons are directly apposed onto microvasculature in the brain and alter local cerebral perfusion [4,5]. Due to the loss of dopaminergic neurons, local cerebral perfusion in PD patients is often altered. 99mTc-HMPAO single-photon emission computed tomography (SPECT) is a well-established method of assessing regional cerebral blood flow (CBF). There seems to be agreement in the pattern of cortical hypoperfusion in PD patients. Many SPECT/PET studies have demonstrated that cortical areas such as the parieto-temporo-occipital cortex, dorsolateral prefrontal cortex and cingulate gyrus often display lower perfusion in PD patients than in healthy controls [6,7]. However, the results regarding basal ganglia and cerebellar perfusion in PD patients have been inconsistent. Some SPECT studies revealed that PD patients have increased CBF in the bilateral putamen, globus pallidus, ventral lateral nucleus of thalamus and cerebellum [6,8,9]. A previous PET study showed that the CBF in the globus pallidus was significantly lower in PD patients than in healthy controls [10]. Some SPECT studies demonstrated no perfusion change in subcortical regions of PD patients compared to healthy controls [11]. These differences may result from the different normalization methods used. Therefore, more studies are needed to confirm the pattern of subcortical and cerebellar regions in PD patients. Although SPECT/PET has been relatively extensively used for studying brain perfusion, some limitations must be taken into consideration, such as low spatial resolution, radioactivity and high expense. By contrast, with many advantages, such as obviating the use of an exogenous contrast agent, offering higher spatial resolution, and having faster acquisition compared to PET, arterial spin labeling (ASL) has been used to study brain perfusion in PD patients. Previous ASL-MRI studies revealed PD patients had lower perfusion than healthy group in many cortical and subcortical regions [12,13], and CBF can be used as a surrogate marker for differential diagnosis between PD and atypical Parkinson’s disease [14]. To date, although some studies have measured brain perfusion in early-stage PD, few studies have used ASL to measure perfusion in the subcortex of advanced PD patients. Moreover, previous findings regarding cerebral perfusion in PD remain inconsistent. Therefore, more ASL studies are needed to further explore the perfusion pattern in PD.