what is it in your brain that makes you crave for cigarettes ?

Question: what is it in your brain that makes you crave for cigarettes ?
- Keywords:
  addiction,
  brain,
  smoking
Asked by nancyxx to Alessandro, Angela, Claudia, Marina, Phil on 18 Mar 2013.
- Marina De Vos answered on 18 Mar 2013:
  
  I do not think it is related to the brain. People get addicted to the nicotine. The absence of it will give a physical reaction (which is of course picked up by the brain). Apart from that I guess it is also the habit of smoking that is desired (social context, perceived emotional benefit).

Question: what is it in your brain that makes you crave for cigarettes ?