chip preparation and placement of brain slice to record high-quality seizure-like activity using cmos-hd-mea system 

<meta charset="utf8"></head><body>Konsekvent induktion och registrering av anfallsliknande aktivitet med användning av CMOS-HD-MEA

Commercially available high-density microelectrode array (HD-MEA) systems, which include an MEA chip with thousands of recording points1,2 and an MEA platform to amplify and digitize the data, are an emerging tool for electrophysiological research. These HD-MEA systems use complementary metal-oxide-semiconductor (CMOS) technology to record electrophysiological data with high sensitivity from cell cultures and ex vivo brain slice preparations. These MEA systems afford unprecedented spatial and temporal resolution to neurophysiological research via high electrode density and quality signal-to-noise ratios3. This technology has mostly been used to study extracellular action potentials, but it can also capture high-quality local field potentials (LFPs) from various neuronal brain slice preparations4,5,6,7,8,9,10,11,12,13,14,15. Due to the above-mentioned high-resolution recording capability of CMOS-HD-MEA systems, users can track electrophysiological activity with great spatial accuracy16,17,18. This capability is particularly relevant to tracking propagation patterns of network LFPs5,12,15,19,20,21. Therefore, CMOS-HD-MEA systems can provide an unprecedented understanding of the propagation patterns of physiological and pathological activity from various cell culture and brain slice preparations. Of particular note, these capabilities of CMOS-HD-MEA systems can allow researchers to contrast seizure patterns of different brain regions simultaneously and assay how various anti-epileptic compounds affect these patterns. By doing so, it provides an innovative method for studying ictogenesis and ictal propagation and for understanding how pharmacology disrupts pathological network activity7,10,14. Therefore, these novel capacities of CMOS-HD-MEA systems can contribute significantly to the research of neurological disorders, as well as aid in drug discovery research5,7,11,22. We aim to provide details on using CMOS-HD-MEA systems to study seizure-like activity.
When using CMOS-HD-MEA systems to study LFPs, such as epileptiform activity in acute brain slices, users can face many challenges, including debilitating electrical noise, keeping the slice healthy during experimentation, and detecting a quality signal from a two-dimensional (2D) CMOS-MEA chip that records only from the surface of the brain slice. This protocol describes basic steps for properly grounding the MEA platform and other equipment used in experimentation, a crucial step that may require individual customization for each lab setup. In addition, we discuss steps to aid in keeping the brain slice healthy during long recordings in the submerged chambers used with CMOS-HD-MEA systems23,24,25. Additionally, in contrast to more common electrophysiological recording methods, which record from deep in the brain slice, most CMOS-HD-MEA systems use 2D chips that do not penetrate into the slice. Therefore, these systems require a healthy neuronal outer layer to produce the majority of the recorded LFP signals. Other challenges include visualizing the massive amount of data generated by thousands of electrodes. To overcome these challenges, we recommend a simple but effective protocol that increases the likelihood of achieving high-quality network epileptiform activity that propagates across the brain slice. We also include a brief description of a publicly available graphic user interface (GUI) we developed with associated resources to aid in data visualization10.
Previous publications have provided related protocols for the use of MEA recording systems26,27,28,29. However, this work aims to assist experimenters using CMOS-HD-MEA systems with 2D chips, specifically those seeking to study high-quality epileptiform activity from brain slices. In addition, we compare two of the most common solution manipulations for induction of seizure-like activity, namely the 0 Mg2+ and 4-AP paradigms, to help users identify the most appropriate convulsant media for their specific application. Although the protocol is focused primarily on the generation of seizure-like activity, it can be modified to explore other electrophysiological phenomena using brain slices.

<meta charset="utf8"></head><body>Författare i fokus: Nysta upp anfallsdynamik och nya terapier för Status Epilepticus med hjälp av CMOS High-Density Microelectrode Array Systems

Högkvalitativ anfallsliknande aktivitet från akuta hjärnskivor med hjälp av ett komplementärt metalloxid-halvledarsystem med mikroelektroder med hög densitet

In the Parrish lab, we are keen on understanding how seizures start, propagate, and terminate. We are particularly interested in exploring novel therapies for status epilepticus, a life-threatening condition in which a seizure does not self-terminate. We use CMOS high-density microelectrode array systems in our research.These advanced technologies allow us to record high resolution electrophysiological data from brain slices, capturing detailed local field potentials. This helps us understand complex brain activities, like seizure patterns, with great spatial and temporal precision. In the future, we plan to explore the spatial and temporal propagation patterns of status epilepticus, a prolonged seizure state that often becomes resistant to anti-epileptic medication.We plan to use the information from these studies to find more effective treatments for status epilepticus.

Chipförberedelse och placering av hjärnskiva för att registrera högkvalitativ anfallsliknande aktivitet med hjälp av CMOS-HD-MEA-system 

chip-preparation-placement-brain-slice-to-record-high-quality-seizure

Research

JoVE Journal

Neuroscience

Chip Preparation and Placement of Brain Slice to Record High-Quality Seizure-like Activity Using CMOS-HD-MEA System 

112 Views. To begin, place a platinum harp in a weighboat near the MEA platform. Then cover the harp with about three milliliters of aCSF to reduce its hydrophobic tendencies. Use scissors to trim about 1.5 inches off the narrow tip of a transfer pipette.Next, use the modified pipette to collect a brain slice from the slice-holding chamber. Gently dispense the brain slice and any solution in the pipette into the chip well. To position the slice properly, use a soft paintbrush to create a current ...