Making sense of brain activity in response to optical manipulation in-vivo in Zebrafish

Introduction: Now the great interest in studying the brain activity based on detection of oscillatory patterns on the recorded data of electrical neuronal activity (electroencephalograms) is associated with the possibility of developing brain-computer interfaces. Braincomputer interfaces are based on the real-time detection of characteristic patterns on electroencephalograms and their transformation into commands for controlling external devices. One of the important areas of the brain-computer interfaces application is the control of the pathological activity of the brain. This is in demand for epilepsy patients, who do not respond to drug treatment.Purpose: A technique for detecting the characteristic patterns of neural activity preceding the occurrence of epileptic seizures.Results:Using multi-channel electroencephalograms, we consider the dynamics of thalamo-cortical brain network, preceded the occurrence of an epileptic seizure. We have developed technique which allows to predict the occurrence of an epileptic seizure. The technique has been implemented in a brain-computer interface, which has been tested in-vivo on the animal model of absence epilepsy.Practical relevance:The results of our study demonstrate the possibility of epileptic seizures prediction based on multichannel electroencephalograms. The obtained results can be used in the development of neurointerfaces for the prediction and prevention of seizures of various types of epilepsy in humans.

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Faculty Opinions recommendation of Flexible, foldable, actively multiplexed, high-density electrode array for mapping brain activity in vivo.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.13386958.14754059 ◽

2011 ◽

Author(s):

Eberhard Fetz ◽

Andrew Richardson

Keyword(s):

Brain Activity ◽

Electrode Array ◽

High Density

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Fiber photometry does not reflect spiking activity in the striatum

10.1101/2021.01.20.427525 ◽

2021 ◽

Author(s):

Alex A. Legaria ◽

Julia A. Licholai ◽

Alexxai V. Kravitz

Keyword(s):

Neuronal Activity ◽

Calcium Imaging ◽

Brain Activity ◽

Neural Population ◽

Fluorescence Signal ◽

Calcium Signals ◽

Cellular Events ◽

Neural Populations ◽

Spiking Activity

AbstractFiber photometry recordings are commonly used as a proxy for neuronal activity, based on the assumption that increases in bulk calcium fluorescence reflect increases in spiking of the underlying neural population. However, this assumption has not been adequately tested. Here, using endoscopic calcium imaging in the striatum we report that the bulk fluorescence signal correlates weakly with somatic calcium signals, suggesting that this signal does not reflect spiking activity, but may instead reflect subthreshold changes in neuropil calcium. Consistent with this suggestion, the bulk fluorescence photometry signal correlated strongly with neuropil calcium signals extracted from these same endoscopic recordings. We further confirmed that photometry did not reflect striatal spiking activity with simultaneous in vivo extracellular electrophysiology and fiber photometry recordings in awake behaving mice. We conclude that the fiber photometry signal should not be considered a proxy for spiking activity in neural populations in the striatum.Significance statementFiber photometry is a technique for recording brain activity that has gained popularity in recent years due to it being an efficient and robust way to record the activity of genetically defined populations of neurons. However, it remains unclear what cellular events are reflected in the photometry signal. While it is often assumed that the photometry signal reflects changes in spiking of the underlying cell population, this has not been adequately tested. Here, we processed calcium imaging recordings to extract both somatic and non-somatic components of the imaging field, as well as a photometry signal from the whole field. Surprisingly, we found that the photometry signal correlated much more strongly with the non-somatic than the somatic signals. This suggests that the photometry signal most strongly reflects subthreshold changes in calcium, and not spiking. We confirmed this point with simultaneous fiber photometry and extracellular spiking recordings, again finding that photometry signals relate poorly to spiking in the striatum. Our results may change interpretations of studies that use fiber photometry as an index of spiking output of neural populations.

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Electro-Metabolic Sensing Through Capillary ATP-Sensitive K+ Channels and Adenosine to Control Cerebral Blood Flow

10.1101/2021.03.12.435152 ◽

2021 ◽

Author(s):

Maria Sancho ◽

Nicholas R. Klug ◽

Amreen Mughal ◽

Thomas J. Heppner ◽

David Hill-Eubanks ◽

...

Keyword(s):

Endothelial Cells ◽

Blood Flow ◽

Cerebral Blood Flow ◽

Vascular Function ◽

Brain Activity ◽

List Type ◽

Capillary Endothelial Cells ◽

Metabolic Sensing ◽

Cellular Components

SUMMARYThe dense network of capillaries composed of capillary endothelial cells (cECs) and pericytes lies in close proximity to all neurons, ideally positioning it to sense neuro/glial-derived compounds that regulate regional and global cerebral perfusion. The membrane potential (VM) of vascular cells serves as the essential output in this scenario, linking brain activity to vascular function. The ATP-sensitive K+ channel (KATP) is a key regulator of vascular VM in other beds, but whether brain capillaries possess functional KATP channels remains unknown. Here, we demonstrate that brain capillary ECs and pericytes express KATP channels that robustly control VM. We further show that the endogenous mediator adenosine acts through A2A receptors and the Gs/cAMP/PKA pathway to activate capillary KATP channels. Moreover, KATP channel stimulation in vivo causes vasodilation and increases cerebral blood flow (CBF). These findings establish the presence of KATP channels in cECs and pericytes and suggest their significant influence on CBF.HIGHLIGHTSCapillary network cellular components—endothelial cells and pericytes—possess functional KATP channels.Activation of KATP channels causes profound hyperpolarization of capillary cell membranes.Capillary KATP channels are activated by exogenous adenosine via A2A receptors and cAMP-dependent protein kinase.KATP channel activation by adenosine or synthetic openers increases cerebral blood flow.

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Development of Optically-Controlled “Living Electrodes” with Long-Projecting Axon Tracts for a Synaptic Brain-Machine Interface

10.1101/333526 ◽

2018 ◽

Cited By ~ 2

Author(s):

Dayo O. Adewole ◽

Laura A. Struzyna ◽

James P. Harris ◽

Ashley D. Nemes ◽

Justin C. Burrell ◽

...

Keyword(s):

Brain Activity ◽

Optical Recording ◽

Neural Interfaces ◽

New Class ◽

Brain Surface ◽

Long Term Performance ◽

Term Performance ◽

The Brain

AbstractAchievements in intracortical neural interfaces are compromised by limitations in specificity and long-term performance. A biological intermediary between devices and the brain may offer improved specificity and longevity through natural synaptic integration with deep neural circuitry, while being accessible on the brain surface for optical read-out/control. Accordingly, we have developed the first “living electrodes” comprised of implantable axonal tracts protected within soft hydrogel cylinders for the biologically-mediated monitoring/modulation of brain activity. Here we demonstrate the controlled fabrication, rapid axonal outgrowth, reproducible cytoarchitecture, and simultaneous optical stimulation and recording of neuronal activity within these engineered constructs in vitro. We also present their transplantation, survival, integration, and optical recording in rat cortex in vivo as a proof-of-concept for this neural interface paradigm. The creation and functional validation of these preformed, axon-based “living electrodes” is a critical step towards developing a new class of biohybrid neural interfaces to probe and modulate native circuitry.

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Cortical oscillations to measure anti-epileptic drug activity in clinical trials

10.21203/rs.3.rs-121959/v1 ◽

2021 ◽

Author(s):

Andrea Biondi ◽

Lorenzo Rocchi ◽

Viviana Santoro ◽

Gregory Beatch ◽

Pierre Rossini ◽

...

Keyword(s):

Clinical Trials ◽

Brain Activity ◽

Systematic Evaluation ◽

Alpha Power ◽

Brain Oscillations ◽

Cortical Oscillations ◽

Anti Epileptic Drug ◽

Beta Power ◽

Gamma Power

Abstract The frequency analysis of electroencephalographic (EEG) activity, either spontaneous or evoked by transcranial magnetic stimulation (TMS-EEG), is a powerful tool to investigate changes in brain activity and excitability following the administration of antiepileptic drugs (AEDs). However, a systematic evaluation of the effect of AEDs on spontaneous and TMS-induced brain oscillations has not yet been provided. We studied the effects of lamotrigine, levetiracetam, and of a novel potassium channel opener (XEN1101) on TMS-induced and spontaneous brain oscillations in a group of healthy volunteers. Levetiracetam suppressed TMS-induced theta, alpha and beta power, whereas lamotrigine increased TMS-induced alpha power. XEN1101 decreased TMS-induced delta, theta and beta power. Resting-state EEG showed a decrease of theta band power after lamotrigine intake. Levetiracetam increased theta, beta and gamma power, while XEN1101 produced an increase of delta, theta, beta and gamma power. Different AEDs induce specific patterns of power changes in spontaneous and TMS-induced brain oscillations. Spontaneous and TMS-induced cortical oscillations represent a powerful tool to characterize the effect of AEDs on in vivo brain activity. Spectral fingerprints of specific AEDs should be further investigated to provide robust and objective biomarkers of biological effect in human clinical trials.

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Parylene photonics: a flexible, broadband optical waveguide platform with integrated micromirrors for biointerfaces

Microsystems & Nanoengineering ◽

10.1038/s41378-020-00186-2 ◽

2020 ◽

Vol 6 (1) ◽

Cited By ~ 1

Author(s):

Jay W. Reddy ◽

Maya Lassiter ◽

Maysamreza Chamanzar

Keyword(s):

Optical Waveguides ◽

Brain Activity ◽

Low Loss ◽

Parylene C ◽

Optogenetic Stimulation ◽

Patterned Illumination ◽

The Brain ◽

532 Nm ◽

Stimulation Of

Abstract Targeted light delivery into biological tissue is needed in applications such as optogenetic stimulation of the brain and in vivo functional or structural imaging of tissue. These applications require very compact, soft, and flexible implants that minimize damage to the tissue. Here, we demonstrate a novel implantable photonic platform based on a high-density, flexible array of ultracompact (30 μm × 5 μm), low-loss (3.2 dB/cm at λ = 680 nm, 4.1 dB/cm at λ = 633 nm, 4.9 dB/cm at λ = 532 nm, 6.1 dB/cm at λ = 450 nm) optical waveguides composed of biocompatible polymers Parylene C and polydimethylsiloxane (PDMS). This photonic platform features unique embedded input/output micromirrors that redirect light from the waveguides perpendicularly to the surface of the array for localized, patterned illumination in tissue. This architecture enables the design of a fully flexible, compact integrated photonic system for applications such as in vivo chronic optogenetic stimulation of brain activity.

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