Millivolt-Scale DC Shifts in the Human Scalp EEG: Evidence for a Nonneuronal Generator

Voipio, Juha; Tallgren, P; Heinonen, Erkki; Vanhatalo, Sampsa; Kaila, Kai

doi:10.1152/jn.00915.2002

Cited by 127 publications

(117 citation statements)

References 44 publications

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“…It has been shown that the negative DC shifts of SD can be detected with scalp DC‐EEG,33, 59 although important ambiguities remain and further research is needed to develop a reliable technique. In the case of abrupt ischemia, recordings might be particularly complicated by large BBB‐generated DC potentials due to p ti O 2 and p ti CO 2 changes 49, 50. Nonetheless, results presented here should have immediate relevance to the biological understanding of human brain death,60 which should at least require the occurrence of terminal SD in cerebral gray matter.…”

Section: Resultsmentioning

confidence: 90%

Terminal spreading depolarization and electrical silence in death of human cerebral cortex

Dreier

Major

Foreman

et al. 2018

Annals of Neurology

120

138

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ObjectiveRestoring the circulation is the primary goal in emergency treatment of cerebral ischemia. However, better understanding of how the brain responds to energy depletion could help predict the time available for resuscitation until irreversible damage and advance development of interventions that prolong this span. Experimentally, injury to central neurons begins only with anoxic depolarization. This potentially reversible, spreading wave typically starts 2 to 5 minutes after the onset of severe ischemia, marking the onset of a toxic intraneuronal change that eventually results in irreversible injury.MethodsTo investigate this in the human brain, we performed recordings with either subdural electrode strips (n = 4) or intraparenchymal electrode arrays (n = 5) in patients with devastating brain injury that resulted in activation of a Do Not Resuscitate–Comfort Care order followed by terminal extubation.ResultsWithdrawal of life‐sustaining therapies produced a decline in brain tissue partial pressure of oxygen (ptiO2) and circulatory arrest. Silencing of spontaneous electrical activity developed simultaneously across regional electrode arrays in 8 patients. This silencing, termed “nonspreading depression,” developed during the steep falling phase of ptiO2 (intraparenchymal sensor, n = 6) at 11 (interquartile range [IQR] = 7–14) mmHg. Terminal spreading depolarizations started to propagate between electrodes 3.9 (IQR = 2.6–6.3) minutes after onset of the final drop in perfusion and 13 to 266 seconds after nonspreading depression. In 1 patient, terminal spreading depolarization induced the initial electrocerebral silence in a spreading depression pattern; circulatory arrest developed thereafter.InterpretationThese results provide fundamental insight into the neurobiology of dying and have important implications for survivable cerebral ischemic insults. Ann Neurol 2018;83:295–310

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Section: Resultsmentioning

confidence: 90%

Terminal spreading depolarization and electrical silence in death of human cerebral cortex

Dreier

Major

Foreman

et al. 2018

Annals of Neurology

120

138

View full text Add to dashboard Cite

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“…16 and this work) frequencies. So far, the lower frequencies have been largely ignored for technical reasons (14,15,19,26). The ISOs described in the present work have properties that are unprecedented in the human EEG literature: a very low frequency of 0.02-0.2 Hz and a slow apparent propagation over cortical hemispheres.…”

Section: Discussionmentioning

confidence: 86%

“…In the present study, we used direct current (DC)-coupled EEG scalp recordings (14)(15)(16) to demonstrate that ISOs are, in fact, a salient, large-scale feature of the human EEG. They were tightly associated with a cyclic modulation of fast EEG activity as well as discrete EEG events such as K complexes and interictal activity.…”

mentioning

confidence: 99%

Infraslow oscillations modulate excitability and interictal epileptic activity in the human cortex during sleep

Vanhatalo

Palva

Holmes

et al. 2004

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

453

397

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Human cortical activity has been intensively examined at frequencies ranging from 0.5 Hz to several hundred Hz. Recent studies have, however, reported also infraslow fluctuations in neuronal population activity, magnitude of electroencephalographic oscillations, discrete sleep events, as well as in the occurrence of interictal events. Here we use direct current electroencephalography to demonstrate large-scale infraslow oscillations in the human cortex at frequencies ranging from 0.02 to 0.2 Hz. These oscillations, which are not detectable in conventional electroencephalography because of its limited recording bandwidth (typical lower limit 0.5 Hz), were observed in widespread cortical regions. Notably, the infraslow oscillations were strongly synchronized with faster activities, as well as with the interictal epileptic events and K complexes. Our findings suggest that the infraslow oscillations represent a slow, cyclic modulation of cortical gross excitability, providing also a putative mechanism for the as yet enigmatic aggravation of epileptic activity during sleep.epilepsy ͉ slow cortical oscillations ͉ phase synchrony ͉ direct current electroencephalography ͉ full-band electroencephalography A large body of literature has characterized functional and clinical correlates of cortical oscillatory activity seen in the human electroencephalography (EEG) at frequencies ranging from 0.5 Hz to several hundred Hz (1). In addition to these relatively fast EEG oscillations, some studies have demonstrated infraslow fluctuations in, for instance, neuronal population activity (2-5), EEG power (5-9), discrete sleep events (arousals, spindles, K complexes) (9-12), as well as in the occurrence of epileptic events (4, 11, 13). These observations have raised the possibility that the human cortex may generate infraslow oscillations (ISOs) underlying such fluctuations. ISOs are not detectable in conventional EEG because of its limited recording bandwidth (typical lower limit, 0.5 Hz; ref. 1).In the present study, we used direct current (DC)-coupled EEG scalp recordings (14-16) to demonstrate that ISOs are, in fact, a salient, large-scale feature of the human EEG. They were tightly associated with a cyclic modulation of fast EEG activity as well as discrete EEG events such as K complexes and interictal activity. In analogy with recent studies demonstrating that slow delta oscillations (0.5-1 Hz) may modulate brain excitability (17, 18), our data points to a role of ISOs in the control of gross cortical excitability. Our findings also provide a window on the modulation of interictal epileptiform events (IIEs) and on sleep-epilepsy interactions in the human brain. MethodsSubjects and EEG Recording. We studied 16 subjects (four females; average age, 34.3 years; range, 16-51 years) during overnight (n ϭ 9) or daytime (n ϭ 7) sleep. This study was approved by the Human Subjects Committee of the University of Washington. Twelve subjects were recorded using a custom-made 16-channel DC-coupled EEG amplifier and Ag͞AgCl electrodes (refs....

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“…We used custom-made Ag/AgCl electrodes placed on short-circuited skin; for details of the recording procedure, see Voipio et al (2003) and Vanhatalo et al (2004). Each subject participated in two 30 min sessions.…”

Section: Methodsmentioning

confidence: 99%

Very Slow EEG Fluctuations Predict the Dynamics of Stimulus Detection and Oscillation Amplitudes in Humans

2008

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Our ability to perceive weak signals is correlated among consecutive trials and fluctuates slowly over time. Although this "streaking effect" has been known for decades, the underlying neural network phenomena have remained largely unidentified. We examined the dynamics of human behavioral performance and its correlation with infraslow (0.01-0.1 Hz) fluctuations in ongoing brain activity. Full-band electroencephalography revealed prominent infraslow fluctuations during the execution of a somatosensory detection task. Similar fluctuations were predominant also in the dynamics of behavioral performance. The subjects' ability to detect the sensory stimuli was strongly correlated with the phase, but not with the amplitude of the infraslow EEG fluctuations. These data thus reveal a direct electrophysiological correlate for the slow fluctuations in human psychophysical performance. We then examined the correlation between the phase of infraslow EEG fluctuations and the amplitude of 1-40 Hz neuronal oscillations in six frequency bands. Like the behavioral performance, the amplitudes in these frequency bands were robustly correlated with the phase of the infraslow fluctuations. These data hence suggest that the infraslow fluctuations reflect the excitability dynamics of cortical networks. We conclude that ongoing 0.01-0.1 Hz EEG fluctuations are prominent and functionally significant during execution of cognitive tasks.

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Millivolt-Scale DC Shifts in the Human Scalp EEG: Evidence for a Nonneuronal Generator

Cited by 127 publications

References 44 publications

Terminal spreading depolarization and electrical silence in death of human cerebral cortex

Terminal spreading depolarization and electrical silence in death of human cerebral cortex

Infraslow oscillations modulate excitability and interictal epileptic activity in the human cortex during sleep

Very Slow EEG Fluctuations Predict the Dynamics of Stimulus Detection and Oscillation Amplitudes in Humans

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