Axis software spontaneous neural configuration

Multi‐electrode array (MEA) analyses of neurons and cortical organoids were performed as described (Nageshappa et al, 2016; Trujillo et al, 2019). Briefly, neurospheres were plated on dual‐chamber MEA; spontaneous spike activity was evaluated with the MED64 System (Panasonic). Glutamatergic (AP5, NBQX), GABAergic (Gabazine), and gap channel (Mefloquine) antagonism were used to verify neuronal activity. Recorded spikes were analyzed using the Neuroexplorer software (Nex Technologies, Madison, AL, USA). For cortical organoids, one‐month‐old organoids were plated on MEA plates and recordings were collected with a Maestro MEA system and AxIS Software Spontaneous Neural Configuration (Axion Biosystems, Atlanta, GA, USA). The plate was incubated in the machine for three minutes before five minutes of recording. Axion Biosystems’s Neural Metrics Tool classified as “active” those electrodes with at least five spikes/minute. Bursts were identified using an inter‐spike interval (ISI) threshold requiring a 5‐spike minimum and 100ms maximum ISI. Network bursts required a minimum of 10 spikes under the same ISI and at least 25% active electrodes.

MEA recordings were achieved as previously described [23 (link), 30 (link)]. Six-week-old cortical organoids were plated in 12-well MEA plates (Axion Biosystems, Atlanta, GA, USA) pre-coated with 100 µg/mL poly-L-ornithine and 10 µg/mL laminin. Cellular cultures were fed twice a week and, 14 days after plating, weekly measurements were performed. Recordings were conducted in a Maestro MEA system with AxIS Software Spontaneous Neural Configuration (Axion Biosystems). Using Axion Biosystems’ Neural Metrics Tool, active electrodes required at least 5 spikes/min. Bursts/electrode used an inter-spike interval (ISI) threshold requiring minimally 5 spikes with a maximum ISI of 100 ms. Network bursts required at least 10 spikes under the same ISI. The synchrony index utilized a cross-correlogram window of 20 ms.