Subthalamic nucleus

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Federal government websites often end in. The site is secure. Because the complex functions of the basal ganglia have been increasingly studied over the past several decades, the understanding of the role of the subthalamic nucleus STN in motor and cognitive functions has evolved. The increased attention focused on such non-motor functions housed within the STN partially arose from the observed cognitive and affective side effects seen with STN deep brain stimulation. The multiple modalities of research have corroborated these findings and have provided converging evidence that the STN is critically involved in cognitive processes. In particular, numerous experiments have demonstrated the involvement of the STN in high-conflict decisions. The different STN functions appear to be related to activity in anatomically distinct subregions, with the ventral STN contributing to high-conflict decision-making through its role in the hyperdirect pathway involving the prefrontal cortex.

Subthalamic nucleus

The Subthalamic Nucleus STh is an oval-shaped diencephalic structure located ventrally to the thalamus, playing a fundamental role in the circuitry of the basal ganglia. However, most of the anatomical evidence available derives from non-human primate studies. In this review, we will present the topographical and morphological organization of the nucleus and its connections to structurally and functionally related regions of the basal ganglia circuitry. We will also highlight the importance of additional research in humans focused on validating STh connectivity, cytoarchitectural organization, and its functional subdivision. The Subthalamic Nucleus STh 1 , also known as Corpus Luysii, is an oval-shaped diencephalic structure located ventrally to the thalamus Allheid et al. Described for the first time by Jules Bernard Luys — , its functions remained largely unknown until , when J. Martin reported the first case of hemichorea following lesion of the STh Martin, As a key structure involved in the pathophysiology of several neurological disorders e. In PD, the progressive loss of dopaminergic neurons in the substantia nigra pars compacta causes an alteration of the striatopallidal and pallidosubthalamical pathways in the basal ganglia, resulting in an abnormal burst-firing pattern in STh neurons Magill et al. DBS modulates STh firing, resulting in improvement in motor and non-motor disability as well as quality of life Grill and Mcintyre, ; Dostrovsky and Lozano, ; Grill et al. However, adverse side effects of the treatment are not to be underestimated Saint-Cyr et al. Even though the authors evidenced no association between the surgical approach to STh DBS and the side effects of the treatment, a possible explanation for cognitive and affective dysfunctions following DBS may reside in the functional subdivision of the STh, which is known to project to different circuits of the basal ganglia in primates Carpenter et al. Thus, the stimulation of specific areas of the nucleus may modulate connectivity within associative and limbic circuits of the basal ganglia Vergani et al.

Lange, subthalamic nucleus, H. This increased subthalamic nucleus activity may lead to excessive inhibition of movement via the basal ganglia circuits mentioned above. The ansa subthalamica: a neglected fiber tract.

The subthalamic nuclei are small paired structures that are part of the functional basal ganglia. They are located ventral to the thalamus , dorsal to the substantia nigra and medial to the internal capsule. The subthalamic nucleus receives its main input from the lateral pallidum external segment of the globus pallidus. Excitatory, glutamatergic inputs come from the cerebral cortex particularly the motor cortex , and from the pars parafascicularis of the central complex. There are also neuromodulatory inputs from the substantia nigra pars compacta.

Federal government websites often end in. Before sharing sensitive information, make sure you're on a federal government site. The site is secure. NCBI Bookshelf. Hayden Basinger ; Joe Joseph. Authors Hayden Basinger 1 ; Joe Joseph 2. The subthalamic nucleus is located at the junction of the midbrain and diencephalon. It is a small lens-shaped structure that functionally participates with the basal ganglia. The subthalamic nucleus contains glutaminergic neurons with projections to the internal globus pallidus. The glutamatergic neurons increase the activity of the internal globus pallidus, which contains GABAergic neurons that, in turn, decrease the activity of the thalamus and inhibit movement.

Subthalamic nucleus

Federal government websites often end in. The site is secure. Because the complex functions of the basal ganglia have been increasingly studied over the past several decades, the understanding of the role of the subthalamic nucleus STN in motor and cognitive functions has evolved. The increased attention focused on such non-motor functions housed within the STN partially arose from the observed cognitive and affective side effects seen with STN deep brain stimulation. The multiple modalities of research have corroborated these findings and have provided converging evidence that the STN is critically involved in cognitive processes. In particular, numerous experiments have demonstrated the involvement of the STN in high-conflict decisions. The different STN functions appear to be related to activity in anatomically distinct subregions, with the ventral STN contributing to high-conflict decision-making through its role in the hyperdirect pathway involving the prefrontal cortex. Because the complex functions of the basal ganglia have been increasingly studied over the past several decades, the understanding of the role of the subthalamic nucleus STN in motor and cognitive function has evolved. The increased attention focused on such nonmotor functions housed within the STN partially arose from the observed cognitive and affective side effects seen with STN DBS.

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In humans, technical limitations determined by silver impregnation techniques, such as the incomplete impregnation of fine structures like axons and smaller dendrites in formalin fixed tissue, do not allow for a complete visualization of axonal branching patterns. Aspects such as the precise termination of SN projections to the STh remain to be clearly determined. NCBI Bookshelf. Subthalamic projections to the Striatum, both Caudate nucleus and Putamen, are scarce compared to other subthalamic targets Nauta and Cole, ; Smith and Parent, ; Parent and Smith, ; Sato et al. Histological studies present inherent technical limitations in reconstructing fiber pathways from the cortex to the STh due to the conspicuous length of the fibers. In an important demonstration of the significance of the different subregions within the STN, two patients experienced reproducible, stimulation-related hypomania with stimulation of ventral contacts confirmed to be within the STN Mallet et al. DBS surgery often involves microelectrode recording of neuronal activity and stimulation of the target structures while the patient remains awake. In one study investigating acute depressive symptoms related to stimulation, electrodes were actually determined to be located outside the STN in the zona incerta Stefurak et al. Efferent connections of cortical area 8 frontal eye field in Macaca Fascicularis. World Neurosurg. Our current understanding of the lymphatics of the brain and spinal cord.

The subthalamic nucleus is a small, oval, section of the subthalamus in the brain, made of gray matter uninsulated nerve fibers. Functionally, it is part of the basal ganglia system. The subthalamic nucleus impacts motor control and may also have a role in psychological processes.

No use, distribution or reproduction is permitted which does not comply with these terms. Dostrovsky, J. The nigro-subthalamical pathway appears to be less prominent in primates than in rodents Parent and Hazrati, The majority of the neurons arising from the subthalamic nucleus are excitatory glutaminergic neurons and project to the internal globus pallidus. As the nonmotor functions of the STN have become increasingly recognized, several groups have taken advantage of the opportunities afforded by these procedures to investigate the changes in STN activity during various cognitive and behavioral tasks. Another critical point in the classical tripartite hypothesis of the STh is the segregation of anatomo-functional circuits; while earlier studies suggested relatively segregated and defined STh subdivisions, more recent evidence points toward overlapping subregions and converging axonal afferents on large dendritic fields of neuronal populations of the structure Percheron et al. Pearce JM. Gerfen, C. Based on this interpretation, a renewed interest in surgical treatments for PD led to the revival of both pallidotomy and subthalamotomy, effective procedures that had largely been abandoned after the discovery of levodopa. Figure 4. Dopaminergic innervation of the basal ganglia in the squirrel monkey, as revealed by tyrosine hydroxylase immunohistochemistry. Surface Pineal gland Habenula Habenular trigone Habenular commissure.