Growing up, Judith Grisel struggled with alcohol, marijuana and cocaine. Now, as a neuroscientist, she's working to understand the biological basis of addiction. Her new book is 'Never Enough.' Grisel talks about how various drugs affect the brain, and her own experience with addiction. Grisel has been clean and sober for 30 years. Also, rock critic Ken Tucker reviews two new albums by guitarists Steve Gunn and Michael Chapman.