scholarly journals The Upper Ascending Reticular Activating System between Intralaminar Thalamic Nuclei and Cerebral Cortex in the Human Brain

2017 ◽  
Vol 29 (3) ◽  
pp. 109-114 ◽  
Author(s):  
Sungho Jang ◽  
Soyoung Kwak
Keyword(s):  
Cerebral Cortex ◽  
Human Brain ◽  
Thalamic Nuclei ◽  
Ascending Reticular Activating System ◽  
Reticular Activating System ◽  
Intralaminar Thalamic Nuclei

Consultation with the specialist

1994 ◽  
Vol 15 (5) ◽  
pp. 204-207
Author(s):  
Jeffrey S. Rubenstein
Keyword(s):  
Cerebral Cortex ◽  
Systemic Disease ◽  
Afferent Neurons ◽  
Altered Consciousness ◽  
Case Presentation ◽  
Good General Health ◽  
Ascending Reticular Activating System ◽  
Reticular Activating System ◽  
The Central Nervous System ◽  
The Brain

Case Presentation A 2-year-old boy is brought to the emergency room by ambulance after being found "unresponsive" by his parents. He has been in good general health, has had no fever or other symptoms of infectious processes, has been taking no medications, and was "his normal self" until immediately prior to being found. Patients who are unresponsive and unarousable are in coma. The term altered consciousness represents the spectrum of abnormalities that exists between the immediate capability for normal wakefulness and true coma. For the purposes of this review, the two terms will be used interchangeably because their causes are similar and usually differ only in severity. Pathophysiology Two areas of the brain are responsible for consciousness: the ascending reticular activating system (ARAS) and the cerebral cortex. The ARAS is located in the brain stem from the level of the medulla to the level of the midbrain and sends multiple afferent neurons to the cortex. Disruption of this system can lead to disorders of consciousness. The cerebral cortex is the much more common site where dysfunction can cause coma. Any injury or illness that affects the cerebral cortex globally can cause coma or altered consciousness. Differential Diagnosis Altered consciousness in children can be caused by injuries or illnesses that affect the central nervous system directly or can be a manifestation of other systemic disease (Table 1).

Change of Ascending Reticular Activating System Following Shunt Operation for Hydrocephalus in a Subarachnoid Hemorrhage Patient

2018 ◽  
Vol 80 (01) ◽  
pp. 062-066
Author(s):  
SungHo Jang ◽  
HanDo Lee
Keyword(s):  
Intraventricular Hemorrhage ◽  
Diffusion Tensor ◽  
External Ventricular Drain ◽  
Brain Magnetic Resonance Imaging ◽  
Shunt Operation ◽  
Neural Connectivity ◽  
Thalamic Nuclei ◽  
Lumbar Drain ◽  
Ascending Reticular Activating System ◽  
Reticular Activating System

Objective To demonstrate the change of the ascending reticular activating system (ARAS) concurrent with the recovery of impaired consciousness following a shunt operation in a stroke patient. Methods A 65-year-old female patient underwent coiling of a ruptured right posterior communicating artery and, subsequently, underwent right external ventricular drain (EVD) placement, left EVD placement, and lumbar drain placement for management of intraventricular hemorrhage. After 6 months from onset, she began rehabilitation, and brain magnetic resonance imaging showed dilatation of the ventricular system. The patient exhibited impaired alertness, with a Glasgow Coma Scale (GCS) score of 7. At ∼ 20 days after starting rehabilitation, the patient underwent a ventriculoperitoneal shunt operation for hydrocephalus. At 10 days postsurgery, her GCS improved to 15. Results Regarding the change of neural connectivity of the thalamic intralaminar nuclei, compared with preoperative diffusion tensor tractography (DTT), postoperative DTT showed that neural connectivity to the prefrontal cortex was increased in both hemispheres. In terms of configuration of DTT, the lower portion of the ARAS between the reticular formation and the intralaminar thalamic nuclei did not show a significant change. Conclusions A patient with subarachnoid and intraventricular hemorrhage showed recovery of an injured ARAS and consciousness after a shunt operation for hydrocephalus.

The Neural Tract Between the Hypothalamus and Basal Forebrain in the Ascending Reticular Activating System: A Diffusion Tensor Tractography Study

2019 ◽  
Vol 15 (4) ◽  
pp. 369-372 ◽  
Author(s):  
Sung Ho Jang ◽  
Hyeok Gyu Kwon
Keyword(s):  
Basal Forebrain ◽  
Diffusion Tensor ◽  
Anterior Commissure ◽  
Normal Subjects ◽  
Diffusion Tensor Tractography ◽  
Reconstruction Method ◽  
Thalamic Nuclei ◽  
System A ◽  
Ascending Reticular Activating System ◽  
Reticular Activating System

<P>Objective: Ascending Reticular Activating System (ARAS) has a key role in consciousness. The ARAS is a complex network consisting of a portion of the brainstem reticular formation, nonspecific thalamic nuclei, hypothalamus, Basal Forebrain (BF), and cerebral cortex. We examined the reconstruction method and features of the neural tract between the hypothalamus and the BF in normal subjects, using Diffusion Tensor Tractography (DTT). Methods: Twenty-three healthy subjects were recruited. The ARAS between the hypothalamus and the BF was reconstructed by two Regions of Interest (ROIs): 1) seed ROI - the isolated green portion for the BF on the color map, 2) target ROI - the hypothalamus on the axial image. DTT parameters of the ARAS between the hypothalamus and the BF were examined. Results: Among 46 hemispheres in 23 normal subjects, 24 hemispheres (52.2 %) were identified in the ARAS between the hypothalamus and the BF. The reconstructed ARAS between the hypothalamus and the BF connected from the hypothalamus to the commissural level and anteriorly through the anterior commissure and then reached the BF. Conclusion: Using DTT, the ARAS between the hypothalamus and the BF was identified in normal subjects. Because the hypothalamus and BF are related to the regulation of wakefulness and sleep, our reconstruction method and results would be useful in the research on sleep and wakefulness aspects of consciousness.</P>

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