scholarly journals Seizure Detection and Network Dynamics of Generalized Convulsive Seizures: Towards Rational Designing of Closed-Loop Neuromodulation

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Puneet Dheer ◽  
Ganne Chaitanya ◽  
Diana Pizarro ◽  
Rosana Esteller ◽  
Kaushik Majumdar ◽  
...  
Keyword(s):  
Closed Loop ◽  
Network Dynamics ◽  
Seizure Detection ◽  
Line Length ◽  
Detection Methods ◽  
Sprague Dawley ◽  
Subcortical Structures ◽  
Clonic Seizures ◽  
Thalamocortical Network ◽  
Convulsive Seizures

Objective. Studies have demonstrated the utility of closed-loop neuromodulation in treating focal onset seizures. There is an utmost need of neurostimulation therapy for generalized tonic-clonic seizures. The study goals are to map the thalamocortical network dynamics during the generalized convulsive seizures and identify targets for reliable seizure detection. Methods. Local field potentials were recorded from bilateral cortex, hippocampi, and centromedian thalami in Sprague-Dawley rats. Pentylenetetrazol was used to induce multiple convulsive seizures. The performances of two automated seizure detection methods (line length and P-operators) as a function of different cortical and subcortical structures were estimated. Multiple linear correlations-Granger’s Causality was used to determine the effective connectivity. Results. Of the 29 generalized tonic-clonic seizures analyzed, line length detected 100% of seizures in all the channels while the P-operator detected only 35% of seizures. The detection latencies were shortest in the thalamus in comparison to the cortex. There was a decrease in amplitude correlation within the thalamocortical network during the seizure, and flow of information was decreased from thalamus to hippocampal-parietal nodes. Significance. The preclinical study confirms thalamus as a superior target for automated detection of generalized seizures and modulation of synchrony to increase coupling may be a strategy to abate seizures.

Five New Things: Seizure Detection Devices

2021 ◽  
pp. 10.1212/CPJ.0000000000001044
Author(s):  
Alexandra Carrick Atwood ◽  
Cornelia Natasha Drees
Keyword(s):  
Heart Rate ◽  
Motion Detection ◽  
Electrodermal Activity ◽  
False Positive Rate ◽  
Seizure Detection ◽  
Mechanisms Of Action ◽  
Unexpected Death ◽  
Positive Rate ◽  
Convulsive Seizures ◽  
Electroencephalogram Eeg

ABSTRACT:Purpose: The purpose of this paper is to review seizure detection devices, their mechanisms of action, efficacy and reflecting upon potential improvements for future devices.Recent Findings: There are five main categories of seizure detection devices ([email protected]), these include electroencephalogram (EEG), heart rate detection (HR), electrodermal activity (EDA), motion detection and electromyography (EMG). These devices can be used in combination or in isolation to detect seizures. These devices are high in their sensitivity for convulsive seizures, but low in specificity because of a tendency to detect artifact. Overall, they perform poorly identifying non-convulsive seizures.Summary: Seizure detection devices are currently most useful in detecting convulsive seizures and thereby might help against sudden unexpected death in epilepsy (SUDEP), though they have a high false positive rate. These devices are much less adept at detecting more clinically subtle seizures.

Research on the Detection of Focusing Mechanisms

2014 ◽  
Vol 599-601 ◽  
pp. 1186-1189
Author(s):  
Fang Mao Chai ◽  
Yan Chao Fan ◽  
Hong Wei Xin ◽  
Zhi Lai Li
Keyword(s):  
Working Conditions ◽  
Closed Loop ◽  
Performance Test ◽  
Step Length ◽  
Detection Methods ◽  
Engineering Practice ◽  
Space Optics ◽  
Remote Sensors ◽  
The Difference ◽  
Relative Detection

Since focusing mechanisms is essential equipment, which could compensate the difference between adjustment environments and working conditions of space optics remote sensors, the detection of it is very important. Based on engineering practice, this paper firstly introduces the basic detection of focusing mechanisms, that is the appearance inspection and the boundary dimension inspection, and then introduces several common performance test projects, that is the detection of stroke, step length, gravity inclination, rock, and empty back and the test of modal, self-locking performance and closed-loop accuracy, and also introduces relative detection methods and cautions. At last it briefs other derivative detection projects.

scholarly journals Inactivation of Prefrontal Cortex Delays Emergence From Sevoflurane Anesthesia

2021 ◽  
Vol 15 ◽  
Author(s):  
Emma R. Huels ◽  
Trent Groenhout ◽  
Christopher W. Fields ◽  
Tiecheng Liu ◽  
George A. Mashour ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Brain Regions ◽  
Association Cortex ◽  
Sprague Dawley ◽  
Subcortical Structures ◽  
Behavioral Arousal ◽  
Barrel Field ◽  
Loss Of Righting Reflex ◽  
Parietal Association Cortex ◽  
Righting Reflex

Studies aimed at investigating brain regions involved in arousal state control have been traditionally limited to subcortical structures. In the current study, we tested the hypothesis that inactivation of prefrontal cortex, but not two subregions within parietal cortex—somatosensory barrel field and medial/lateral parietal association cortex—would suppress arousal, as measured by an increase in anesthetic sensitivity. Male and female Sprague Dawley rats were surgically prepared for recording electroencephalogram and bilateral infusion into prefrontal cortex (N = 13), somatosensory barrel field (N = 10), or medial/lateral parietal association cortex (N = 9). After at least 10 days of post-surgical recovery, 156 μM tetrodotoxin or saline was microinjected into one of the cortical sites. Ninety minutes after injection, rats were anesthetized with 2.5% sevoflurane and the time to loss of righting reflex, a surrogate for loss of consciousness, was measured. Sevoflurane was stopped after 45 min and the time to return of righting reflex, a surrogate for return of consciousness, was measured. Tetrodotoxin-mediated inactivation of all three cortical sites decreased (p < 0.05) the time to loss of righting reflex. By contrast, only inactivation of prefrontal cortex, but not somatosensory barrel field or medial/lateral parietal association cortex, increased (p < 0.001) the time to return of righting reflex. Burst suppression ratio was not altered following inactivation of any of the cortical sites, suggesting that there was no global effect due to pharmacologic lesion. These findings demonstrate that prefrontal cortex plays a causal role in emergence from anesthesia and behavioral arousal.

scholarly journals Restoring ventilatory control using an adaptive bioelectronic system

2018 ◽  
Author(s):  
Ricardo Siu ◽  
James J Abbas ◽  
Brian K Hillen ◽  
Jefferson Gomes ◽  
Stefany Coxe ◽  
...  
Keyword(s):  
Closed Loop ◽  
In Vivo Studies ◽  
Sprague Dawley ◽  
Stimulation Parameters ◽  
Sprague Dawley Rats ◽  
Volume Profile ◽  
Stimulation Pattern ◽  
Stimulation Of

Ventilatory pacing via electrical stimulation of the phrenic nerve or of the diaphragm has been shown to enhance quality of life compared to mechanical ventilation. However, commercially-available ventilatory pacing devices require initial manual specification of stimulation parameters and frequent adjustment to achieve and maintain suitable ventilation over long periods of time. Here, we have developed an adaptive, closed-loop, neuromorphic, pattern-shaping controller capable of automatically determining a suitable stimulation pattern and adapting it to maintain a desired breath volume profile on a breath-by-breath basis. In vivo studies in anesthetized intact and C2-hemisected male Sprague-Dawley rats indicated that the controller was capable of automatically adapting stimulation parameters to attain a desired volume profile. Despite diaphragm hemiparesis, the controller was able to achieve a desired volume in the injured animals that did not differ from the tidal volume observed prior to injury (p=0.39). The closed-loop controller was developed and parametrized in a computational testbed prior to in-vivo assessment. This bioelectronic technology could serve as an individualized and autonomous respiratory pacing approach for support or recovery from ventilatory deficiency.

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