Wang, JunJung, Woo-BinGertner, RonaPark, HongkunHam, Donhee2025-02-122025-02-11Wang, Jun, Woo-Bin Jung, Rona Gertner, Hongkun Park, Donhee Ham. "Synaptic connectivity mapping among thousands of neurons via parallelized intracellular recording with a microhole electrode array." Nat. Biomed. Eng No Volume. DOI: 10.1038/s41551-025-01352-52157-846Xhttps://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37380381Massive parallelization of neuronal intracellular recording, which can measure synaptic signals across a network and thus can enable the mapping and characterization of synaptic connections, is a challenge still open in neuroscience, with the state-of-the-art limited to a mapping of ~300 synaptic connections. Here, we report a 4,096 platinum/platinum-black microhole electrode array fabricated on a complementary metal-oxide semiconductor electronic chip that substantially advances parallel intracellular recording and synaptic connectivity mapping. The microhole-neuron interface, together with current-clamp electronics in the underlying semiconductor chip, allows 90% average intracellular coupling rate with rat neuronal cultures, generating network-wide intracellular recording data that abound with synaptic signals. From these data we extract 70,000+ plausible synaptic connections amongst 2,000+ neurons, and catalogue them into inhibitory, weak/uneventful excitatory, and strong/eventful excitatory chemical synaptic connections, and electrical synaptic connections, with an estimated overall error rate of around 5%. The reported scale of synaptic connection mapping, with the ability to characterize synaptic connections, provides a step toward functional connectivity mapping of a large-scale neuronal network.en-USJournal Article2025-02-1210.1038/s41551-025-01352-5