Assessing the Effects of Toxins on Chick Embryo Neural Network Development Using Multielectrode Arrays

Begin with adherent cultures of early embryonic chick neurons on extracellular matrix-coated multielectrode arrays, or MEAs.

The base of the MEAs contains grids of tiny electrodes that record neuronal activity.

In the test culture, neurons grow in the presence of a toxin, while in the control culture, neurons grow without the toxin.

Before recording, replace the media in both MEAs with toxin-free media and incubate briefly.

Next, place one MEA in the recording device and begin recording.

Neurons communicate via electrical impulses called action potentials or spikes.

At the synapse, these action potentials trigger neurotransmitter release, propagating the signal to the next neuron.

The MEA electrodes record the spikes generated by the synaptically connected neurons. 

In the control condition, the healthy mature neuronal network exhibits synchronous spiking activity.

In the test culture, reduced spiking and synchrony suggest impaired neuronal network maturation caused by the toxin.

On the day of acquisition, replace the culture medium with fresh neurobasal medium, and return the arrays to the CO₂ incubator for a minimum of two hours before recording. Start the recording software and set the temperature of the multi-electrode array to 37 degrees Celsius by clicking on the temperature icon. Set the acquisition parameters by selecting streams in the left window panel, and right-clicking on the muse icon. Then, select Add Processing and Spike Detector and click OK in the pop-up window. Spike Detector 6 by STD will appear below the file name.

Next, right-click on the Spike Detector, select Add Processing and Burst Detector, and click OK in the pop-up window. Burst Detector ISI will appear below the muse icon. Then right-click on Burst Detector, select Add Processing and Neural Statistics Compiler. In the pop-up window, ensure that File Header, Aggregated Well Statistics, and Synchrony are selected. Click OK.

Statistics Compiler will appear below. Click on the clock icon at the bottom of the screen and change the information in the Settings section to record every 5.1 minutes and record for five minutes. This will be started immediately and will be executed once. After retrieving the multi-electrode array from the incubator, place it on the recording unit and lock it into place. Start recording the network activity by clicking on Start Record in the scheduled recording section.