Outside of certain circles at MIT, you’d be hard pressed to find someone who is familiar with the biotech startup Galenea. The Cambridge, MA-based firm has been researching drugs for schizophrenia and other neurological disorders for more than five years, yet it has done so with a unique funding strategy that has kept its significant operation under the radar.

Galenea, founded in 2003 by MIT professor and Nobel laureate Susumu Tonegawa and others, has received the majority of its funding from the Japanese drug maker Otsuka Pharmaceutical, Mark Benjamin, the firm’s CEO, said. The startup has never raised a round of venture capital. And the company’s founders, employees, and Otsuka own the company.

Otsuka Pharmaceutical, a unit of Otsuka Holdings, began collaborating with Galenea in January 2005 and will have pumped $90 million into the startup’s research by the end of 2011. A focus of the collaboration has been on a defective protein, studied in Tonegawa’s lab at MIT and at Rockefeller University, which is believed to play a role in schizophrenia and other neurological dysfunctions. The aim is to find drugs that can modify the activity of the protein enough to treat a variety of mental disorders…