Normalization of Aperiodic Electrocorticography Components Indicates Fine Motor Recovery After Sensory Cortical Stroke in Mice

Biskamp, Jonatan; Cainzos, Sara Isla; Higgen, Focko L.; Gerloff, Christian; Magnus, Tim

doi:10.1161/strokeaha.122.039335

Cited by 3 publications

(2 citation statements)

References 58 publications

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“…We recently evidenced how the Spectral Exponent (SE) of the EEG is a powerful neurophysiological fingerprint of stroke (11). The EEG SE describes the 1/f-like structure of the Power Spectral Sensity (PSD) (12) and is consistently steeper in the Affected Hemisphere (AH), a finding also confirmed in animal models (13).…”

Section: Introductionmentioning

confidence: 70%

Spectral exponent assessment and neurofilament light chain: a comprehensive approach to describe recovery patterns in stroke

Lanzone,

Zulueta,

Boscarino

et al. 2024

Front. Neurol.

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IntroductionUnderstanding the residual recovery potential in stroke patients is crucial for tailoring effective neurorehabilitation programs. We propose using EEG and plasmatic Neurofilament light chain (NfL) levels as a model to depict longitudinal patterns of stroke recovery.MethodsWe enrolled 13 patients (4 female, mean age 74.7 ± 8.8) who underwent stroke in the previous month and were hospitalized for 2-months rehabilitation. Patients underwent blood withdrawal, clinical evaluation and high-definition EEG at T1 (first week of rehabilitation) and at T2 (53 ± 10 days after). We assessed the levels of NfL and we analyzed the EEG signal extracting Spectral Exponent (SE) values. We compared our variables between the two timepoint and between cortical and non-cortical strokes.ResultsWe found a significant difference in the symmetry of SE values between cortical and non-cortical stroke at both T1 (p = 0.005) and T2 (p = 0.01). SE in the affected hemisphere showed significantly steeper values at T1 when compared with T2 (p = 0.001). EEG measures were consistently related to clinical scores, while NfL at T1 was related to the volume of ischemic lesions (r = 0.75; p = 0.003). Additionally, the combined use of NfL and SE indicated varying trends in longitudinal clinical recovery.ConclusionWe present proof of concept of a promising approach for the characterization of different recovery patterns in stroke patients.

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Section: Introductionmentioning

confidence: 70%

Spectral exponent assessment and neurofilament light chain: a comprehensive approach to describe recovery patterns in stroke

Lanzone,

Zulueta,

Boscarino

et al. 2024

Front. Neurol.

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“…qEEG measures include more complex indices such as delta/theta ratio (DTR), the delta/alpha ratio (DAR), and the (delta + theta)/(alpha + beta) ratio (DTABR). In an animal model of middle cerebral artery occlusion, the aperiodic spectral exponents—i.e., a putative marker of disrupted, inefficient neural communication—in peri-infarct area increased transiently and this correlated to a better recovery ( 48 ). Indeed, measures that asses the 1/f shape of the EEG spectrum have been proposed as a comprehensive way to assess the excitation/inhibition balance that is inherently expressed in EEG ( 49 ).…”

Section: Neurophysiological Changes During the Acute Phasementioning

confidence: 99%

The role of neurophysiological tools in the evaluation of ischemic stroke evolution: a narrative review

Motolese¹,

Lanzone²,

Todisco³

et al. 2023

Front. Neurol.

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Ischemic stroke is characterized by a complex cascade of events starting from vessel occlusion. The term “penumbra” denotes the area of severely hypo-perfused brain tissue surrounding the ischemic core that can be potentially recovered if blood flow is reestablished. From the neurophysiological perspective, there are local alterations—reflecting the loss of function of the core and the penumbra—and widespread changes in neural networks functioning, since structural and functional connectivity is disrupted. These dynamic changes are closely related to blood flow in the affected area. However, the pathological process of stroke does not end after the acute phase, but it determines a long-term cascade of events, including changes of cortical excitability, that are quite precocious and might precede clinical evolution. Neurophysiological tools—such as Transcranial Magnetic Stimulation (TMS) or Electroencephalography (EEG)—have enough time resolution to efficiently reflect the pathological changes occurring after stroke. Even if they do not have a role in acute stroke management, EEG and TMS might be helpful for monitoring ischemia evolution—also in the sub-acute and chronic stages. The present review aims to describe the changes occurring in the infarcted area after stroke from the neurophysiological perspective, starting from the acute to the chronic phase.

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The Excessive Tonic Inhibition of the Peri-infarct Cortex Depresses Low Gamma Rhythm Power During Poststroke Recovery

Alasoadura,

Leclerc,

Hazime

et al. 2024

J. Neurosci.

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The cortex immediately surrounding a brain ischemic lesion, the peri-infarct cortex, harbors a large part of the potential to recover lost functions. However, our understanding of the neurophysiological conditions in which synaptic plasticity operates, remains limited. Here we hypothesized that the chronic imbalance between excitation and inhibition of the peri-infarct cortex prevents the normalization of the gamma rhythm, a waveband of neural oscillations thought to orchestrate action potential trafficking. Probing the local field potential activity of the forelimb primary sensory cortex (S1FL) located in the peri-infarct cortex of male adult mice, we found a constant, deep reduction of low-gamma oscillation power (L-gamma; 30-50 Hz) precisely during the critical time window for recovery (1 to 3 weeks after stroke). The collapse of L-gamma power negatively corelated with behavioral progress in affected forelimb use. Mapping astrocyte reactivity and GABA-like immunoreactivity in the peri-infarct cortex revealed a parallel high signal, which gradually increased when approaching the lesion. Increasing tonic inhibition with local infusion of GABA or by blocking its recapture reduced L-gamma oscillation power in a magnitude similar to stroke. Conversely, the negative allosteric modulation of tonic GABA conductance using L655,708 or the gliopeptide ODN rescued the L-gamma power of the peri-infarct cortex. Altogether the present data point-out that the chronic excess of ambient GABA in the peri-infarct cortex limits the generation of L-gamma oscillations in the repairing cortex and suggests that rehabilitative interventions aimed at normalizing low-gamma power within the critical period of stroke recovery could optimize the restitution of lost functions.Significance StatementAfter a stroke, the recovery of lost motor function depends on the reorganization of surviving neural networks. However, the excitation/inhibition balance in the repairing area is suboptimal as it leans excessively towards inhibition. In this work, using an in vivo approach, we demonstrate here that this imbalance, occurring during the critical window for recovery, leads to the collapse of gamma oscillations, a crucial cerebral rhythm for organizing neural communication. This study reinforces the concept of timely therapeutic interventions aimed at correcting the pathological oscillatory regimen of stroke recovery to enhance plasticity.

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Normalization of Aperiodic Electrocorticography Components Indicates Fine Motor Recovery After Sensory Cortical Stroke in Mice

Cited by 3 publications

References 58 publications

Spectral exponent assessment and neurofilament light chain: a comprehensive approach to describe recovery patterns in stroke

Spectral exponent assessment and neurofilament light chain: a comprehensive approach to describe recovery patterns in stroke

The role of neurophysiological tools in the evaluation of ischemic stroke evolution: a narrative review

The Excessive Tonic Inhibition of the Peri-infarct Cortex Depresses Low Gamma Rhythm Power During Poststroke Recovery

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