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Sung Ho Jang - One of the best experts on this subject based on the ideXlab platform.
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The relationship between consciousness and the ascending Reticular Activating System in patients with traumatic brain injury
2020Co-Authors: Sung Ho Jang, Young Hyeon KwonAbstract:Abstract Background: We investigated the relationship between consciousness and the ascending Reticular Activating System(ARAS) by using diffusion tensor tractography(DTT) in patients with traumatic brain injury(TBI).Methods: Twenty-six patients with TBI and 13 healthy control subjects were recruited for this study. Glasgow Coma Scale(GCS) scores were used for evaluation of subject consciousness state at the chronic stage of TBI(at DTT scanning), According to the GCS score, the patient group was divided into two subgroups: A(14 patients;impaired consciousness:GCS score<15, and B(12 patients;intact consciousness;GCS score=15). Fractional anisotropy(FA) and tract volume(TV) values were assessed in the lower dorsal and upper ARAS.Results: The FA values of the lower dorsal ARAS and the upper ARAS in patient subgroup A were significantly lower than those in patient subgroup B and the control group(p<0.05). However, the FA and TV values for the lower dorsal ARAS and the upper ARAS were not significantly different between patient subgroup B and the control group(p>0.05). The FA value of the lower dorsal ARAS(r=0.473,p<0.05) and the TV of upper ARAS(r=0.484,p<0.05) had moderate positive correlations with the GCS score. The FA value of the upper ARAS had a strong positive correlation with the GCS score of the patient group(r=0.780,p<0.05).Conclusions: We detected a close relationship between consciousness at the chronic stage of TBI and injuries of the lower dorsal and upper ARAS(especially, the upper ARAS) in patients who showed impaired consciousness at the onset of TBI. We believe that our results can be useful during the development of therapeutic strategies for patients with impaired consciousness following TBI.Trial registration: YUMC 2019-06-032-003. retrospectively registered 06 Jun 2020.
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effect of repetitive transcranial magnetic stimulation on the ascending Reticular Activating System in a patient with disorder of consciousness a case report
BMC Neurology, 2020Co-Authors: Sung Ho Jang, Young Hyeon KwonAbstract:We report on a stroke patient with disorder of consciousness (DOC) who underwent repetitive transcranial magnetic stimulation (rTMS) and showed recovery of an injured upper ascending Reticular Activating System (ARAS) injury, which was demonstrated by using serial diffusion tensor tractography (DTT). A 45-year-old male patient was diagnosed as subarachnoid and intracerebral hemorrhages in the left fronto-parieto-temporal lobes. At 5 months after onset, the patient exhibited a persistent vegetative state, with a Coma Recovery Scale-Revised (CRS-R) score of 4. He underwent comprehensive rehabilitative therapy that included drugs for recovery of impaired consciousness and rTMS of the right dorsolateral prefrontal lobe. He recovered to a minimally conscious state (CRS-R: 13) at 7 months after onset and was transferred to a local rehabilitation hospital where he underwent similar rehabilitation but without rTMS. At 9 months after onset, his CRS-R score remained at 13. He was then readmitted to our hospital and underwent rehabilitation with rTMS until 10 months after onset. His CRS-R remained at 13, but his higher cognition had improved. The tract volume (TV) of the neural tract in the right prefrontal lobe in the upper ARAS on the 7-month DTT was higher than that on the 5-month DTT. However, compared to the 7-month DTT, the right prefrontal lobe TV was lower on the 9-month DTT. On the 10-month DTT, the TV of that neural tract had again increased. Increases in neural TV in the right prefrontal lobe of the upper ARAS that were associated with the periods of rTMS application were demonstrated in a stroke patient with DOC.
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The Relation Between Loss of Consciousness, Severity of Traumatic Brain Injury, and Injury of Ascending Reticular Activating System in Patients With Traumatic Brain Injury.
American Journal of Physical Medicine & Rehabilitation, 2019Co-Authors: Sung Ho JangAbstract:OBJECTIVE: Loss of consciousness is an indicator of the severity of traumatic brain injury and the ascending Reticular Activating System has been considered as a main structure for consciousness. However, no study on the relation between loss of consciousness and ascending Reticular Activating System injury in traumatic brain injury has been reported. We investigated the relation between loss of consciousness, severity of traumatic brain injury, and ascending Reticular Activating System injury using diffusion tensor tractography. DESIGN: One hundred twenty patients were recruited. Three components of ascending Reticular Activating System, fractional anisotropy, and tract volume were measured. RESULTS: In lower dorsal and ventral ascending Reticular Activating System, fractional anisotropy and tract volume value in mild group were higher than those of moderate and severe groups, and there was no difference between moderate and severe groups. In upper ascending Reticular Activating System, fractional anisotropy value in mild group was higher than in moderate group, and it was higher than in moderate group than in severe group. Tract volume value in mild group was higher than in severe group. Loss of consciousness showed moderate negative correlations with tract volume value of lower dorsal ascending Reticular Activating System (r = -0.348), fractional anisotropy value of lower ventral ascending Reticular Activating System (r = -0.343), and fractional anisotropy value of upper ascending Reticular Activating System (r = -0.416). CONCLUSIONS: Injury severity was different among the three traumatic brain injury groups in upper ascending Reticular Activating System but did not differ between moderate and severe groups in lower dorsal and ventral ascending Reticular Activating System.
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relationship between impaired consciousness and injury of ascending Reticular Activating System in patients with intracerebral hemorrhage
Stroke, 2019Co-Authors: Sung Ho Jang, Chul Hoon Chang, Young Jin Jung, Young Hyeon KwonAbstract:Background and Purpose— We investigated the relationship between impaired consciousness and ascending Reticular Activating System (ARAS) characteristics on diffusion tensor tractography during the ...
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difference in the ascending Reticular Activating System injury between mild traumatic brain injury and cerebral concussion
Translational Neuroscience, 2019Co-Authors: Sung Ho JangAbstract:Introduction: We investigated differences in the ascending Reticular Activating System (ARAS) injuries between patients with mild traumatic brain injury (mTBI) and cerebral concussion by using diffusion tensor tractography (DTT). Methods: Thirty-one patients with mTBI, 29 patients with concussion, and 30 control subjects were recruited. We used DTT to reconstruct the lower ventral and dorsal ARAS, and the upper ARAS. The fractional anisotropy (FA) value and the fiber number (FN) of the lower ventral and dorsal ARAS, and the upper ARAS were determined. Results: Significant differences were observed in the FA values of the lower ventral and dorsal ARAS on both sides between the mTBI and control groups and between the concussion and control groups (p < 0.05). The FN value was significantly different in the lower ventral ARAS on both sides between the concussion and control groups and between the mTBI and concussion groups (p < 0.05). Conclusion: Both the mTBI and concussion patients suffered injuries in the lower ventral and dorsal ARAS, with the concussion patients exhibiting more severe injury in the ventral ARAS than that in the mTBI patients. These results suggest that the terms mTBI and concussion should be used differentially, even though they have used interchangeably for a long time.
Hyeok Gyu Kwon - One of the best experts on this subject based on the ideXlab platform.
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injury of ascending Reticular Activating System associated with delayed post hypoxic leukoencephalopathy a case report
BMC Neurology, 2017Co-Authors: Sung Ho Jang, Hyeok Gyu KwonAbstract:Abstract Background Delayed post-hypoxic leukoencephalopathy (DPHL) is a demyelinating syndrome characterized by neurological relapse after an initial recovery from hypoxic brain injury. We describe a patient with impaired consciousness following DPHL, concurrent with injury of the ascending Reticular Activating System (ARAS) shown using diffusion tensor tractography (DTT). Case presentation A 50-year-old male patient was in a drowsy mental state after exposure to carbon monoxide (CO) for about ten hours. About a day after the CO exposure, his mental state recovered to an alert condition. However, his consciousness deteriorated to drowsy 24 days after the exposure and worsened to a semi-coma state at 26 days after onset. When he started rehabilitation six weeks after the CO exposure, he had impaired consciousness, with a Glasgow Coma Scale score of 8 and a Coma Recovery Scale-Revised score of 8. On 6-week DTT, decreased neural connectivity of the upper ARAS between the intralaminar thalamic nucleus and the cerebral cortex was observed in both frontal cortices, basal forebrains, basal ganglia and thalami. The lower dorsal ARAS was not reconstructed on the right side, and was thin on the left side. The lower ventral ARAS was not reconstructed on either side. Conclusions Using DTT, we demonstrated injury of the ARAS in a patient with impaired consciousness following DPHL. Our result suggests that injury of the ARAS is a plausible pathogenetic mechanism of impaired consciousness in patients with DPHL.
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aggravation of excessive daytime sleepiness concurrent with aggravation of an injured ascending Reticular Activating System in a patient with mild traumatic brain injury a case report
Medicine, 2017Co-Authors: Sung Ho Jang, Hyeok Gyu KwonAbstract:AbstractBackground:We report on a patient who developed aggravation of excessive daytime sleepiness (EDS) concurrent with aggravation of an injured ascending Reticular Activating System (ARAS) following mild traumatic brain injury (TBI), demonstrated by follow-up diffusion tensor tractographies (DTT
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hypersomnia due to injury of the ventral ascending Reticular Activating System following cerebellar herniation a case report
Medicine, 2017Co-Authors: Sung Ho Jang, Chul Hoon Chang, Young Jin Jung, Hyeok Gyu KwonAbstract:RATIONALE: We report on a patient with hypersomnia who showed injury of the lower ascending Reticular Activating System (ARAS) following cerebellar herniation due to a cerebellar infarct, detected on diffusion tensor tractography (DTT). PATIENT CONCERNS: A 53-year-old male patient was diagnosed as a left cerebellar infarct, and underwent decompressive suboccipital craniectomy due to brain edema at 2 days after the onset of a cerebellar infarct. Three weeks after onset when the patient started rehabilitation, he showed hypersomnia without impairment of consciousness; he fell asleep most of daytime without external stimulation and showed an abnormal score on the Epworth Sleepiness Scale: 15 (full score: 24, cut off for hypersomnia: 10). DIAGNOSES AND OUTCOMES: On 3-week DTT, narrowing of the upper portion of the lower ventral ARAS between the pontine Reticular formation and the hypothalamus was observed on both sides. In addition, partial tearing was observed in the middle portion of the right lower ventral ARAS. LESSONS: In conclusion, we found injury of the lower ventral ARAS in a patient with hypersomnia following cerebellar herniation due to a cerebellar infarct.
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injury of the ascending Reticular Activating System in patients with fatigue and hypersomnia following mild traumatic brain injury two case reports
Medicine, 2016Co-Authors: Sung Ho Jang, Hyeok Gyu KwonAbstract:We report on patients with post-traumatic fatigue and hypersomnia who showed injury of the lower portion of the ascending Reticular Activating System (ARAS) between the pontine Reticular formation (RF) and the intralaminar thalamic nucleus (ILN) following mild traumatic brain injury (TBI), using diffusion tensor tractography (DTT). Two patients with mild TBI resulting from a car accident were enrolled in this study. Patient 1 was a 51-year-old woman showed abnormalities as 6.9 (cut off: 3.7 points) and 18 (cut off: 10) on the Fatigue Severity Scale and the Epworth Sleepiness Scale at 11 months after onset. Patient 2 was a 64-year-old woman who revealed abnormalities on the Fatigue Severity Scale and the Epworth Sleepiness Scale with 6.8 and 19 at 3 months after onset. In both patients, the upper ARAS in which the neural connectivity of the ILN to the cerebral cortex did not show significant abnormalities. However, we observed the narrowing of the left dorsal lower ARAS between the pontine RF and the ILN in both patients and the tearing (patient 1) and narrowing (patient 2) of the left ventral lower ARAS between the pontine RF and the hypothalamus. Injuries of the dorsal and ventral lower ARAS were demonstrated in patients with fatigue and hypersomnia following mild TBI. We believe that these injuries of the ARAS might be a pathogenetic mechanism of fatigue and hypersomnia in patients with TBI.
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the direct pathway from the brainstem Reticular formation to the cerebral cortex in the ascending Reticular Activating System a diffusion tensor imaging study
Neuroscience Letters, 2015Co-Authors: Sung Ho Jang, Hyeok Gyu KwonAbstract:Precise evaluation of the ascending Reticular Activating System (ARAS) is important for diagnosis, prediction of prognosis, and management of patients with disorders of impaired consciousness. In the current study, we attempted to reconstruct the direct neural pathway between the brainstem Reticular formation (RF) and the cerebral cortex in normal subjects, using diffusion tensor imaging (DTI). Forty-one healthy subjects were recruited for this study. DTIs were performed using a sensitivity-encoding head coil at 1.5Tesla with FMRIB Software Library. For connectivity of the brainstem RF, we used two regions of interest (ROIs) for the brainstem RF (seed ROI) and the thalamus and hypothalamus (exclusion ROI). Connectivity was defined as the incidence of connection between the brainstem RF and target brain regions at the threshold of 5 and 50 streamlines. Regarding the thresholds of 5 and 50, the brainstem RF showed high connectivity to the lateral prefrontal cortex (lPFC, 67.1% and 20.7%) and ventromedial prefrontal cortex (vmPFC, 50.0% and 18.3%), respectively. In contrast, the brainstem RF showed low connectivity to the primary motor cortex (31.7% and 3.7%), premotor cortex (24.4% and 3.7%), primary somatosensory cortex (23.2% and 2.4%), orbitofrontal cortex (17.1% and 7.3%), and posterior parietal cortex (12.2% and 0%), respectively. The brainstem RF was mainly connected to the prefrontal cortex, particularly lPFC and vmPFC. We believe that the methodology and results of this study would be useful to clinicians involved in the care of patients with impaired consciousness and researchers in studies of the ARAS.
Victoria L. Morgan - One of the best experts on this subject based on the ideXlab platform.
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Relating structural and functional brainstem connectivity to disease measures in epilepsy
Neurology, 2018Co-Authors: Dario J Englot, Bryson B. Reynolds, Monica L Jacobs, Hernán F J González, John C Gore, Bennett A. Landman, Peter E. Konrad, Victoria L. MorganAbstract:Objective While epilepsy studies rarely examine brainstem, we sought to examine the hypothesis that temporal lobe epilepsy (TLE) leads to subcortical arousal center dysfunction, contributing to neocortical connectivity and neurocognitive disturbances. Methods In this case-control study of 26 adult patients with TLE and 26 controls, we used MRI to measure structural and functional connectivity of the cuneiform/subcuneiform nuclei (CSC), pedunculopontine nucleus, and ventral tegmental area. Ascending Reticular Activating System connectivity patterns were related to neuropsychological and disease measures. Results Compared to controls, patients with TLE demonstrated reductions in ascending Reticular Activating System structural and functional connectivity, most prominently to neocortical regions (p Conclusions Connectivity perturbations in brainstem arousal centers are present in TLE and may contribute to neurocognitive problems. These studies demonstrate the underappreciated role of brainstem networks in epilepsy and may lead to novel neuromodulation targets to treat or prevent deleterious brain network effects of seizures in TLE.
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functional connectivity disturbances of the ascending Reticular Activating System in temporal lobe epilepsy
Journal of Neurology Neurosurgery and Psychiatry, 2017Co-Authors: Monica L Jacobs, Victoria L. Morgan, Dario J Englot, John C Gore, Peter E. Konrad, Pierrefrancois Dhaese, Bassel AboukhalilAbstract:Objective Seizures in temporal lobe epilepsy (TLE) disturb brain networks and lead to connectivity disturbances. We previously hypothesised that recurrent seizures in TLE may lead to abnormal connections involving subcortical Activating structures including the ascending Reticular Activating System (ARAS), contributing to neocortical dysfunction and neurocognitive impairments. However, no studies of ARAS connectivity have been previously reported in patients with epilepsy. Methods We used resting-state functional MRI recordings in 27 patients with TLE (67% right sided) and 27 matched controls to examine functional connectivity (partial correlation) between eight brainstem ARAS structures and 105 cortical/subcortical regions. ARAS nuclei included: cuneiform/subcuneiform, dorsal raphe, locus coeruleus, median raphe, parabrachial complex, pontine oralis, pedunculopontine and ventral tegmental area. Connectivity patterns were related to disease and neuropsychological parameters. Results In control subjects, regions showing highest connectivity to ARAS structures included limbic structures, thalamus and certain neocortical areas, which is consistent with prior studies of ARAS projections. Overall, ARAS connectivity was significantly lower in patients with TLE than controls (p Conclusions Recurrent seizures in TLE are associated with disturbances in ARAS connectivity, which are part of the widespread network dysfunction that may be related to neurocognitive problems in this devastating disorder.
Young Hyeon Kwon - One of the best experts on this subject based on the ideXlab platform.
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The relationship between consciousness and the ascending Reticular Activating System in patients with traumatic brain injury
2020Co-Authors: Sung Ho Jang, Young Hyeon KwonAbstract:Abstract Background: We investigated the relationship between consciousness and the ascending Reticular Activating System(ARAS) by using diffusion tensor tractography(DTT) in patients with traumatic brain injury(TBI).Methods: Twenty-six patients with TBI and 13 healthy control subjects were recruited for this study. Glasgow Coma Scale(GCS) scores were used for evaluation of subject consciousness state at the chronic stage of TBI(at DTT scanning), According to the GCS score, the patient group was divided into two subgroups: A(14 patients;impaired consciousness:GCS score<15, and B(12 patients;intact consciousness;GCS score=15). Fractional anisotropy(FA) and tract volume(TV) values were assessed in the lower dorsal and upper ARAS.Results: The FA values of the lower dorsal ARAS and the upper ARAS in patient subgroup A were significantly lower than those in patient subgroup B and the control group(p<0.05). However, the FA and TV values for the lower dorsal ARAS and the upper ARAS were not significantly different between patient subgroup B and the control group(p>0.05). The FA value of the lower dorsal ARAS(r=0.473,p<0.05) and the TV of upper ARAS(r=0.484,p<0.05) had moderate positive correlations with the GCS score. The FA value of the upper ARAS had a strong positive correlation with the GCS score of the patient group(r=0.780,p<0.05).Conclusions: We detected a close relationship between consciousness at the chronic stage of TBI and injuries of the lower dorsal and upper ARAS(especially, the upper ARAS) in patients who showed impaired consciousness at the onset of TBI. We believe that our results can be useful during the development of therapeutic strategies for patients with impaired consciousness following TBI.Trial registration: YUMC 2019-06-032-003. retrospectively registered 06 Jun 2020.
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effect of repetitive transcranial magnetic stimulation on the ascending Reticular Activating System in a patient with disorder of consciousness a case report
BMC Neurology, 2020Co-Authors: Sung Ho Jang, Young Hyeon KwonAbstract:We report on a stroke patient with disorder of consciousness (DOC) who underwent repetitive transcranial magnetic stimulation (rTMS) and showed recovery of an injured upper ascending Reticular Activating System (ARAS) injury, which was demonstrated by using serial diffusion tensor tractography (DTT). A 45-year-old male patient was diagnosed as subarachnoid and intracerebral hemorrhages in the left fronto-parieto-temporal lobes. At 5 months after onset, the patient exhibited a persistent vegetative state, with a Coma Recovery Scale-Revised (CRS-R) score of 4. He underwent comprehensive rehabilitative therapy that included drugs for recovery of impaired consciousness and rTMS of the right dorsolateral prefrontal lobe. He recovered to a minimally conscious state (CRS-R: 13) at 7 months after onset and was transferred to a local rehabilitation hospital where he underwent similar rehabilitation but without rTMS. At 9 months after onset, his CRS-R score remained at 13. He was then readmitted to our hospital and underwent rehabilitation with rTMS until 10 months after onset. His CRS-R remained at 13, but his higher cognition had improved. The tract volume (TV) of the neural tract in the right prefrontal lobe in the upper ARAS on the 7-month DTT was higher than that on the 5-month DTT. However, compared to the 7-month DTT, the right prefrontal lobe TV was lower on the 9-month DTT. On the 10-month DTT, the TV of that neural tract had again increased. Increases in neural TV in the right prefrontal lobe of the upper ARAS that were associated with the periods of rTMS application were demonstrated in a stroke patient with DOC.
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relationship between impaired consciousness and injury of ascending Reticular Activating System in patients with intracerebral hemorrhage
Stroke, 2019Co-Authors: Sung Ho Jang, Chul Hoon Chang, Young Jin Jung, Young Hyeon KwonAbstract:Background and Purpose— We investigated the relationship between impaired consciousness and ascending Reticular Activating System (ARAS) characteristics on diffusion tensor tractography during the ...
Jeongyon Shim - One of the best experts on this subject based on the ideXlab platform.
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A flexible intelligent associative knowledge structure of Reticular Activating System : Positive/negative masking
2020Co-Authors: Jeongyon ShimAbstract:As the information circumstance is getting more complicated, the requirements for implementing the efficient intelligent System adopting human brain functions is getting high. We focus on the function of Reticular Activating System which takes charge of information selection.In this paper we designed Reticular Activating System with Positive/Negative masking in the associative memory and Thinking chain extraction mechanism specially implemented for flexible memory structure. The proposed Reticular Activating System has Knowledge acquisition, selection, storing, reconfiguration and retrieving part. P/N masking mechanism for flexible memory is specially designed and tested with virtual memory.
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a design of Reticular Activating System based on p n type matching selection
Annual Conference on Computers, 2006Co-Authors: Jeongyon ShimAbstract:As the information circumstance is getting more complicated, the requirements for implementing the efficient intelligent System adopting human brain functions is getting high. We focus on the function of Reticular Activating System which takes charge of information selection. In this paper we designed P/N Type Matching Selection in Reticular Activating System for the efficient memory retention and retrieval. Type definition and P/N Type matching selection mechanism are specially implemented for flexible memory structure. This mechanism was applied to virtual memory and tested.
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a flexible intelligent associative knowledge structure of Reticular Activating System positive negative masking
Soft Computing, 2006Co-Authors: Jeongyon ShimAbstract:As the information circumstance is getting more complicated, the requirements for implementing the efficient intelligent System adopting human brain functions is getting high. We focus on the function of Reticular Activating System which takes charge of information selection.In this paper we designed Reticular Activating System with Positive/Negative masking in the associative memory and Thinking chain extraction mechanism specially implemented for flexible memory structure. The proposed Reticular Activating System has Knowledge acquisition, selection, storing, reconfiguration and retrieving part. P/N masking mechanism for flexible memory is specially designed and tested with virtual memory.
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on off switching mechanism in knowledge structure of Reticular Activating System
Affective Computing and Intelligent Interaction, 2005Co-Authors: Jeongyon ShimAbstract:Reticular Activating System which has a form of small neural networks in the brain is closely related System with the automatic nervous System. It takes charge of the function that distinguishes between memorizing one and the others, accepts the only selected information and discards the unnecessary things.In this paper, we propose Reticular Activating System which has Knowledge acquisition, selection, storing, reconfiguration and retrieving part. In this paper, On/Off Switching mechanism for flexible memory is specially designed and tested.
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ACII - On/Off switching mechanism in knowledge structure of Reticular Activating System
Affective Computing and Intelligent Interaction, 2005Co-Authors: Jeongyon ShimAbstract:Reticular Activating System which has a form of small neural networks in the brain is closely related System with the automatic nervous System. It takes charge of the function that distinguishes between memorizing one and the others, accepts the only selected information and discards the unnecessary things.In this paper, we propose Reticular Activating System which has Knowledge acquisition, selection, storing, reconfiguration and retrieving part. In this paper, On/Off Switching mechanism for flexible memory is specially designed and tested.
