Controlling, Mapping, and Modeling Neural Circuits

## The study This lesson introduces *Developmental xenocortication using human-derived organoids in mice* (Nature, 2026). The work was a **collaboration** involving multiple Stanford groups and investigators; it should not be attributed to a single lab. ## The problem it addresses Organoids in a dish stay immature and unconnected. Earlier transplants placed organoids into a host cortex that was already developing, so human tissue had to compete with native mouse cortex for space and connections. ## Creating developmental space The study used an **apallial mouse**: a host engineered so that development of its own pallium — the embryonic region that normally gives rise to the neocortex — is largely depleted. This leaves *available developmental space* where cortex would normally form. Human cortical organoid-derived tissue was then **transplanted neonatally** into this space. **Xenocortication**, as the authors use the term, refers to this developmental strategy: human-derived cortical tissue developing in the place of the depleted host cortex. ## The experimental logic CREATE SPACE → TRANSPLANT → MEASURE DEVELOPMENT → TEST CIRCUIT INTEGRATION → MEASURE FUNCTIONAL ACTIVITY → STUDY HOST BEHAVIOR Each step asks a different question, answered with a different technique: - **Histology and anatomical imaging:** how large did the tissue grow, and how is it organized? - **Single-nucleus RNA sequencing and molecular analyses:** which human cortical cell identities developed? - **Anatomical tracing:** does the tissue connect with the host nervous system? - **Calcium imaging and electrophysiology:** is the tissue active, and is the activity organized? - **Behavioral testing:** how do host animals behave? ## Design matters The value of the design is that each claim is tied to a specific measurement. Growth is shown by anatomy; identity by molecular profiling; activity by recordings. This is the map–record–perturb–model framework applied to a human-derived developmental model. ## The course framework GENES → CELL TYPES → CIRCUITS → NETWORK DYNAMICS → BEHAVIOR, studied by four complementary approaches: **map**, **record**, **perturb**, and **model**. Understanding a neural circuit requires several of these ways of observing and testing the same biological system. ## Further reading - [Deisseroth Lab (Stanford)](https://web.stanford.edu/group/dlab/) - Developmental xenocortication using human-derived organoids in mice. *Nature* (2026) — collaborative work by multiple Stanford groups and investigators.