Fig. 5: Mapping information flow through a human brain organoid slice.

a Extracellular action potential spike events are shown from two correlated spike-sorted units. b The spike time latency distribution is shown between the two spike-sorted units shown in a. The latency distribution between pairwise spike events is unimodal (Hartigans’ dip test for multimodality, p = 0.998), with a mean latency of 5.1 ms and a FWHM of 6.1 ms. The inset shows the pairwise spike correlation was calculated using the spike time tile coefficient (STTC) as a function of correlation time window (Δt) for the two correlated spike-sorted units shown in a. Choosing a correlation time window Δt = 20 ms captures all pairwise spike interactions between the two units. c Functional connectivity map showing the pairwise correlation strength (edge thickness in gray) between spike trains. Sorted by directionality, the in-degree and out-degree were computed per unit, defined as predominately incoming or outgoing edges respectively and designated “receiver” (blue) nodes, “sender” (red) nodes. All other nodes were labeled “brokers” (gray with a fixed size not indicative of node degree). For visual clarity, only the top 90 outgoing and the top 90 incoming edges are shown for “sender” and “receiver” nodes, respectively. d Examples of single “sender” (1), “receiver” (2) and “broker” (3) nodes showing all incoming (blue) and outgoing (red) edges for the spatial sites identified on c. The relative fraction of sender, receiver and broker edges remained similar across multiple organoids (n = 4, Supplementary Fig. 12a, b). e Functional connectivity map of the same organoid after treatment with 50 µM diazepam.