Figure 2.
Electrophysiological properties of mature hypothalamus organoids
(A) Transmitted light image of a hypothalamus organoid in a well of a 48-well MEA plate. Scale bar: 300 μm. MEA, multi-electrode array.
(B) Representative example of individual action potentials recorded from a single electrode, marked with a blue arrowhead in C (top), of an MEA plate. An overlay of 40 peak-aligned spikes is shown in gray with the average spike waveform in black.
(C) Top: Electrical activity from five individual MEA electrodes recorded during an organoid-wide network activity burst. Bottom: A compound spike-time histogram from all electrodes overlaid with its CWT. Color bar indicates CWT power. CWT, continuous wavelet transform.
(D) Top: Comparison of mean firing rate of hypothalamus organoids (left) and mean intra-burst frequency, or frequency of spiking within the network burst (right), in s −1 for 1 week (blue = D101) and 2 weeks (black = D108) on the MEA plate. Each data point indicates an individual organoid and the error bars represent SD. s−1, inverse second or per second; wk., week; SD, standard deviation. Bottom: Comparison of the mean N of spikes in the network burst (left) and the area under cross-correlation of spike times (right). Statistical significance was derived by unpaired Student’s t test. p values: ∗∗ = p < 0.01. N = number.