Monitoring the Brain Cortex with a Multi-Electrode Array in Response to Seizure-Inducing Agents

Abstract

Source: Lu, H. C., et al. Direct-current stimulation and multi-electrode array recording of seizure-like activity in mice brain slice preparation. J. Vis. Exp. (2016).

In this video, the effects of transcranial direct-current stimulation (tDCS) on brain slices containing the anterior cingulate cortex (ACC) and thalamus regions are investigated, using a multi-electrode array (MEA) to measure electric signals. By delivering electric pulses and infusing seizure-inducing drugs, the study investigates the ACC response to seizures.

Protocol

All procedures involving animal samples have been reviewed and approved by the appropriate animal ethical review committee.

1. Preparing Experimental Solution and Equipment for MEA (Multielectrode Array) Recording

1. Prepare artificial cerebral spinal fluid (aCSF; 124 mM NaCl, 4.4 mM KCl, 1 mM NaH₂PO₃, 2 mM MgSO₄, 2 mM CaCl₂, 25 mM NaHCO₃, and 10 mM glucose, bubbled with 95% O₂ and 5% CO₂).
2. Use two types of MEA probes: 6 x 10 planar MEA and 8 x 8 MEA. The former probe covers the region that comprises the cortex, striatum, and tha....

Results

Figure 1: Preparation of the Thalamocingulate Slice and MEA Recording System Setup. (A) MT-ACC slice procedure (a) Remove the brain and (b) transfer to cool oxygenated aCSF. (c) Make two parasagittal cuts from the midline. (d) Side view of the medial part .......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Isoflurane	Halocarbon Products Corporation	NDC 12164-002-25	4%
aCSF (total:1 L):
D(+)-Glucose	MERCK	1.08337.1000	10 mM
Sodium hydrogen carbonate	MERCK	1.06329.0500	25 mM
Sodium chloride	MERCK	1.06404.1000	124 mM
(+)-Sodium L-ascorbate, >=98%	SIGMA	A4034-100G	0.15 g/2 c.c
Magnesium sulfate, anhydrous, ReagentPlus	SIGMA	M7506-500G	2 mM
Calcium chloride dihydrate	MERCK	1.02382.1000	2 mM
Sodium dihydrogen phosphate monohydrate	MERCK	1.06346.1000	1 mM
Potassium chloride	May & Baker LTD Dagenham England	MS 7616	4.4 mM
(+)-Bicuculline	TOCRIS	130	5 µM in aCSF
4-Aminopyridine	TOCRIS	940	250 µM in aCSF
Vibratome	Vibratome	Series 1000	Block slicing into 500 µm thick slices
Multielectrode array (MEA) probes: 6 x 10 planar MEA	Multi Channel Systems	60MEA500/30iR-Ti-pr MEAS 6x10	electrode diameter, 30 µm; electrode spacing, 500 µm; impedance, 50 kΩ at 200 Hz
Multielectrode array (MEA) probes: 8 x 8 MEA	Ayanda Biosystems	60MEA200/10iR-Ti-pr MEAS 8x8	pyramidal-shaped electrode; diameter, 40 µm; tip height, 50 µm; electrode spacing, 200 µm; impedance, 1,000 kΩ at 200 Hz
A 60-channel amplifier was used with a band-pass filter set between 0.1 Hz and 3 KHz at 1,200X amplification	Multi-Channel Systems	MEA-1060-BC
MC Rack software at a 10 KHz sampling rate	Multi-Channel Systems		Software for data collect and recordings
control of a pulse generator	Multi-Channel Systems	STG 1002
slice anchor kits and hold-downs	Warner Instruments	SHD-26H/10; WI64-0250
Peristaltic Pump-minipuls3	Gilsom	MINIPULS3	perfusion rate : 8 ml/min
Isolated stimulator	A-M Systems	Model 2100	intensity of ±350 μA , duration of 200 μsec
Tungsten electrode	A-M Systems	575300	placed in thalamus