A Northwestern University neuroscience graduate has pleaded not guilty to charges he pushed another man off a Chicago subway platform and onto train tracks.

Chad Estep is charged with attempted murder, unlawful restraint and aggravated battery. He stood silently in Cook County court on Monday as his attorney entered the plea on his behalf. The 34-year-old is free on $200,000 bond.

His attorney, Vadim Glozman, told reporters the defense will try "to get the best possible result" for Estep.

Police say Estep pushed the 46-year-old man at a downtown station Aug. 1. Estep was arrested earlier this month.

Prosecutors allege Estep tried to block the man from getting back onto the platform and stop other commuters from assisting him. The man climbed onto the platform seconds before a train arrived.