I was wondering what are the after effects, if any, of a brain biopsy?

Should be minimal: A stereotactic brain biopsy is done where a small needle is inserted into the brain under computer guidance. Care is taken to avoid hitting any important structures (blood vessels, nerves). There certainly are risks anytime one is operating in the brain. Depending on the location, there can be weakness/paralysis, and bleeding which can lead to stroke like symptoms, coma, death.