Change: et.et al. 2007). Cravings occur when the euphoria subsides and persist as long as this area of the brain remains activated (Fowler, J. S., et al. 2007). Chronic exposure to the drug reduces the availability of dopamine transporters,   View changes from previous version. (Word count: 293)

Change:  Chronic exposure to the drug reduces the availability of dopamine transporters, indicating a loss of dopamine cells (Fowler, J. S., et. al. 2007). Fewer dopamine transporters are associated with poor memory, low moods and slower motor function (Fowler, J. S., et al. 2007).Go to Step ThreeSee Home Page   View changes from previous version. (Word count: 293)

Change: There were only format changes (bold, italics, etc.) in this version. See this version for details. (Word count: 286)

Change:  records memories of intense emotional responses and associates them with the activity that produced those responses. This helps us focus on seeking out activities that will produce pleasure and promote survival and avoid activities associated with pain, fear, or trauma (Nestler, E. J. 2005). Drugs are more   View changes from previous version. (Word count: 286)