The spooky season can be a divisive one. Some of us love being scared, and others avoid it at all costs. Author Stephen King has been terrifying readers for nearly 50 years, and knows what makes us scream. So how does he do it, and what’s happening in our brains when we’re afraid? Does anything frighten the king of horror? Sanjay Gupta talks to King, one of his favorite writers, about his latest book, “Holly,” and the benefits of fear in everyday life.