At the conclusion of his time at
Lund University, Gage moved to
San Diego, where he became a faculty member in the
University of California, San Diego, neuroscience department. In 1995, he moved to the
Salk Institute, where he still works. Until then, it had been assumed that humans are born with all the brain cells they will ever have. Gage's laboratory showed that, contrary to years of dogma, human beings are capable of growing new nerve cells throughout life. Furthermore, his team is examining the underlying molecular mechanisms that are critical to the birth of new brain cells—work that may lead to new therapeutics for neurodegenerative conditions. His laboratory studies the genomic mosaicism that exists in the brain as a result of "jumping genes", mobile elements, and DNA damage that occurs during development. Specifically, he is interested in how this mosaicism may lead to difference in brain function between individuals. His laboratory published work showing that human induced pluripotent stem cells (hiPSCs) erase aging signatures and hiPSC-derived neurons remain rejuvenated, while direct conversion into induced neurons (iNs) preserve donor fibroblast age-dependent transcriptomic signatures. In October 2004, he participated in the XIIth
Mind and Life Institute conference in
Dharamsala, India, on the theme of neuroplasticity and spoke with the
14th Dalai Lama about his research demonstrating the generation of new nerve cells in the adult brain. ==Relationship with Phineas Gage==