Effect on the Electro-Encephalogram of Certain Drugs Which Influence Nervous Activity

Gibbs, Frederic A.; Gibbs, Erna L.; Lennox, William G.

doi:10.1001/archinte.1937.00180010159012

Cited by 278 publications

(104 citation statements)

References 8 publications

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“…We postulate, based on our modeling studies, that spatially coherent alpha oscillations contribute to propofol-induced unconsciousness by drastically restricting communication within frontal thalamo-cortical circuits to this narrow frequency band (39). Several studies have shown that low-frequency oscillations are more prominent with increasing anesthetic dose and levels of unconsciousness (6,8,21,22,25). In recent multiscale human intracranial studies of propofol-induced unconsciousness, Lewis et al (46) found that neuronal spiking is limited to a brief phase window of the slow oscillation, and is silent otherwise.…”

Section: Discussionmentioning

confidence: 82%

mentioning

confidence: 99%

“…The first EEG recordings in humans under GA, reported in 1937, revealed systematic changes with increasing doses of both ether and pentobarbital (6). Despite attempts to characterize EEG morphology under GA (6)(7)(8)(9), reading the EEG has not become part of routine anesthesiology practice. Instead, a simpler approach is used: Present-day depth-of-anesthesia monitors compute proprietary indices that reduce the EEG to a single, easy-tointerpret number intended to represent a patient's level of unconsciousness (10)(11)(12)(13)(14)(15).…”

mentioning

confidence: 99%

“…The black-box approach of these indices obscures structure in the EEG signal, visible even in 1937 (6), that could be related directly to the state of consciousness in the same way that the electrocardiogram, blood pressure, and cardiac output can be related to the state of the cardiovascular system. A variety of EEG patterns are known to arise during GA maintained by both GABA A receptor-specific and ether-derived anesthetics.…”

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confidence: 99%

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Electroencephalogram signatures of loss and recovery of consciousness from propofol

Purdon

Pierce

Mukamel

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

693

849

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Significance Anesthesiologists reversibly manipulate the brain function of nearly 60,000 patients each day, but brain-state monitoring is not an accepted practice in anesthesia care because markers that reliably track changes in level of consciousness under general anesthesia have yet to be identified. We found specific behavioral and electrophysiological changes that mark the transition between consciousness and unconsciousness induced by propofol, one of the most commonly used anesthetic drugs. Our results provide insights into the mechanisms of propofol-induced unconsciousness and establish EEG signatures of this brain state that could be used to monitor the brain activity of patients receiving general anesthesia.

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Section: Discussionmentioning

confidence: 82%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Electroencephalogram signatures of loss and recovery of consciousness from propofol

Purdon

Pierce

Mukamel

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

693

849

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“…It has been known since the 1930s that for most anesthetic agents, increasing depth of anesthesia correlates with lower-frequency, higher-power EEG oscillations until the onset of burst suppression (25). As a result, many depth-of-anesthesia measures, including multiple commercially available options, depend upon the frequency range that contains the dominant power.…”

Section: Roc From Isoflurane Anesthesia Is a Series Of Transitions Bementioning

confidence: 99%

Recovery of consciousness is mediated by a network of discrete metastable activity states

Hudson

Calderon

Pfaff

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

156

175

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It is not clear how, after a large perturbation, the brain explores the vast space of potential neuronal activity states to recover those compatible with consciousness. Here, we analyze recovery from pharmacologically induced coma to show that neuronal activity en route to consciousness is confined to a low-dimensional subspace. In this subspace, neuronal activity forms discrete metastable states persistent on the scale of minutes. The network of transitions that links these metastable states is structured such that some states form hubs that connect groups of otherwise disconnected states. Although many paths through the network are possible, to ultimately enter the activity state compatible with consciousness, the brain must first pass through these hubs in an orderly fashion. This organization of metastable states, along with dramatic dimensionality reduction, significantly simplifies the task of sampling the parameter space to recover the state consistent with wakefulness on a physiologically relevant timescale.anesthesia | state transitions | spectral analysis | emergence T he brain exhibits a remarkable ability to recover normal function associated with wakefulness, even after large perturbations to its activity. Two well-known examples of this are anesthesia and brain injury (1, 2). How the brain recovers from large perturbations currently is unknown. Given the number of neurons involved, the potential space of activity is huge. Thus, it is not clear how the brain samples the vast parameter space to discover patterns of activity that are consistent with consciousness after a large perturbation.The simplest possibility for the recovery of consciousness (ROC) is that, driven by noise inherent in many aspects of neuronal activity (3), the brain performs a random walk through the parameter space until it eventually enters the region that is consistent with consciousness. An alternative possibility is that although the motion through the parameter space is not random, the trajectory nonetheless is smooth. Lastly, it is possible that en route to ROC, the brain passes through a set of discrete metastable states-that is, a series of jumps between long-lived activity configurations.The utility of metastable intermediates to the problem of ROC is well illustrated by analogy with protein folding. Levinthal's paradox (4) refers to the implausibility of a denatured protein recovering its native fold conformation by random walk alone, as the time required to randomly explore the conformational space will rapidly exceed the age of the universe, even for a small number of residues. (ii), a "small-world" structure, in which most states are connected only locally whereas a few central hub states connect widely, allowing rapid long-distance travel through the network; and (iii) a lattice structure, in which all states have approximately the same connectivity, allowing multiple routes to ROC.In this report, we demonstrate that in rats under isoflurane anesthesia, ROC occurs after the brain traverses a series of metastable in...

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Significance of Focal Delta Activity In Adult Electroencephalogram

Joynt¹,

Cape²,

Knott³

1965

Archives of Neurology

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Effect on the Electro-Encephalogram of Certain Drugs Which Influence Nervous Activity

Cited by 278 publications

References 8 publications

Electroencephalogram signatures of loss and recovery of consciousness from propofol

Electroencephalogram signatures of loss and recovery of consciousness from propofol

Recovery of consciousness is mediated by a network of discrete metastable activity states

Significance of Focal Delta Activity In Adult Electroencephalogram

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