San Francisco -- Lumosity, a San Francisco-based developer of online and mobile games designed to train core cognitive abilities such as memory and attention, said it has raised $31.5 million in its fourth round of funding, led by Discovery Communications, the media company behind such cable TV staples as the Discovery Channel, TLC and Animal Planet. Previous backers FirstMark Capital, Harrison Metal, Menlo Ventures and Norwest Venture Partners also participated in the round, which the company will use to continue its research into human cognitive performance, build its brand, and extend its user base. The company now has received more than $70 million in founding since its inception in 2007. Lumosity's online brain exercises have attracted more than 25 million users, and its mobile app has been downloaded 10 million times since launching in 2010. "Discovery's commitment to igniting people's curiosity and passion for learning is a natural fit with Lumosity's success in brain training," said JB Perrette, Discoewry's chief digital officer.