China
Africa
Explore chapters and articles related to this topic
The subthalamic nucleus: anatomy and neurophysiology
Published in Hans O Lüders, Deep Brain Stimulation and Epilepsy, 2020
Excitatory inputs to the STN from the caudal intralaminar thalamic nuclei represent another important source of glutamatergic inputs to the STN. This projection respects the functional organization of the STN (as outlined above); sensorimotor neurons, originating in the thalamic centromedian nucleus (CM), terminate preferentially in the lateral part of the STN, whereas neurons related to limbic or associative functions, originating in the thalamic para-fascicular nucleus (Pf) project to the medial STN.27–29 The thalamosubthalamic projection is excitatory and may tonically drive the activity of STN neurons, as suggested by studies investigating the effects of lesions of the intralaminar thalamic nuclei on subthalamic nucleus discharge rates.30 Although some CM/Pf neurons that project to the striatum send axon collaterals to the STN,31 most of the the thalamosubthalamic and thalamostriatal projections arise from different CM/Pf neurons.32
Neurotransmitters and Receptors in the Basal Ganglia
Published in W. R. Wayne Martin, Functional Imaging in Movement Disorders, 2019
The MGP and SNr send inhibitory GABAergic projections to the ventral tier nuclei of the thalamus.3,5,6 They also send minor projections to the intralaminar thalamic nuclei and to various brainstem nuclei.3,5,6 The ventral medial thalamus to which the SNr projects sends excitatory projections to the entire frontal lobe in the rat36 and, in primates, to the prefrontal cortex with only minor projections to the premotor and supplementary motor cortices.37,38 The MGP sends its major projection to the ventral lateral thalamic nucleus pars oralis, which in turn projects solely to the supplementary motor cortex.39 The neurotransmitter of the excitatory thalamocortical pathway is unknown. Within the cerebral cortex itself, there are interconnections between supplementary motor cortex and other motor cortical regions.
Basal Forebrain Organization: An Anatomical Framework for Motor Aspects of Drive and Motivation
Published in Peter W. Kalivas, Charles D. Barnes, Limbic Motor Circuits and Neuropsychiatry, 2019
Lennart Heimer, George F. Alheid, Daniel S. Zahm
The ventral striatum and the extended amygdala receive cortical input from frontal and temporal proisocortical areas, from periallocortical and allocortical regions and from the cortical-like basolateral amygdala. Prominent inputs also reach these systems from midline and intralaminar thalamic nuclei. The cortical relationships of these basal forebrain systems will not be discussed further, nor will we deal specifically with the thalamic input. These subjects have been the focus of several recent review chapters and articles,50,85–87,129,144–148 and they are also discussed by Deutch et al. in chapter 2 of this volume. Suffice it to say that the cortical projection systems to the ventral striatum and extended amygdala are characterized by a specific topography, which is likely to translate into functional specificity in the descending projections from these basal forebrain systems.
Fronto-parietal coherence response to tDCS modulation in patients with disorders of consciousness
Published in International Journal of Neuroscience, 2018
Yang Bai, Xiaoyu Xia, Yong Wang, Yongkun Guo, Yi Yang, Jianghong He, Xiaoli Li
In clinical practice, resting state electroencephalography (EEG) recordings are often used as a tool to help clinicians with diagnosis and prognosis [18]. EEG connectivity allows clinicians to easily measure the functional relationships between neocortical regions. Laureys et al explored the connectivity of patients with DoC in order to evaluate brains with MCS and UWS. They found disconnections between the intralaminar thalamic nuclei and prefrontal and anterior cingulate cortices in patients suffering from DoC. In addition, patients with damaged hemispheres conveyed a drop in coherence compared to those with normal hemispheres [19]. Decreases in functional connectivity have been found in MCS patients using measures of coherence [20] and in UWS patients using measures of synchrony [21]. In comparing MCS and UWS patients, EEG connectivity showed that the latter had better connected networks than the former [22]. Thus, the level of connectivity seems to be related to the severity of the consciousness disorder. Lehembre and Marie-Aurelie reported a correlation between connectivity measures and coma recovery scale-revised (CRS-R) scores [22]. Another study found that patients with severe neurocognitive disorders displayed a higher number of connections than those found in MCS patients [23]. Overall, these studies indicate that EEG connectivity may be a suitable way to evaluate the brain responses of patients with DoC in the tDCS protocol.