Dig into what causes the tip of the tongue phenomenon, where your brain struggles to recall a word or term from memory.

Brain fog, forgetfulness, memory problems... Is it ADHD, depression, or even early signs of dementia?

When Henry Molaison (now widely known as H.M.) cracked his skull in an accident, he began blacking out and having seizures. In an attempt to cure him, daredevil surgeon Dr. William Skoville removed H.M.'s hippocampus. Luckily, the seizures did go away — b...