Marito Hayashi is a postdoctoral fellow in the lab of Stephen Liberles at Harvard Medical School. He received his undergraduate degree from International Christian University. He completed his doctoral training with Samuel Pfaff at the Salk Institute and the University of California, San Diego, where he studied the development, organization and function of spinal cord neurons underlying movement control. As a postdoctoral fellow, Hayashi studies the sensory mechanisms and functional organization of the gut-brain axis, focusing on sensory epithelial cells of the gastrointestinal tract.

Project: Gut-brain communication and sensory processing in autism

Signals emanating from the gut control multiple physiological and behavioral programs that are frequently altered in individuals with autism, such as gastrointestinal physiology, metabolism, gut microbiome and post-ingestive learning critical for the development of food preferences. The primary sensory cells within the gastrointestinal tract are termed enteroendocrine cells (EECs). EECs serve as the gateway into the gut-brain axis; signal detection by EECs leads to hormone secretion that impacts downstream pathways involving enteric neurons, vagal sensory neurons and dorsal root ganglion sensory neurons, ultimately regulating a myriad of physiological and behavioral adaptations. However, it is not well understood how signal detection by EECs leads to these diverse responses, nor, importantly, how autism alters gut-brain circuits. The overarching goal of this project is to elucidate the first sensory steps of the gut-brain axis and discover how signal detection in different EEC subtypes recruits ensembles of sensory neurons in neurotypical individuals and in those with autism, thereby providing mechanistic insights into interoceptive changes in autism. When completed, our research will comprehensively chart the molecular and neuronal underpinnings of gut-brain communication in both cohorts, making progress toward the development of diagnostic and therapeutic strategies targeting the gut-brain axis.