Our laboratory studies the brain serotonin matrix and its interactions with other cellular elements. Serotonin molecules are ancient signal carriers that control the behavior of a shark, the cognition of a human, and many other vertebrate neuroprocesses. In particular, we are interested in the stochastic organization of serotonin-releasing axons and their functional relationships with microglia and blood platelets. Some of these problems have immediate clinical relevance: nearly all mental disorders have been associated with dysfunction in serotonin signaling, and the platelet hyperserotonemia of autism remains an enigma after half a century of research. We use a wide range of approaches that include molecular neurobiology, comparative neuroanatomy, and complex-systems methods.