Research by Dr Zamboni and others has shown that people with multiple sclerosis have low cerebral blood flow---Be aware of this new study by Dr. Daniel Amen before choosing to use marijuana.

".....researchers using single photon emission computed tomography (SPECT), a sophisticated imaging study that evaluates blood flow and activity patterns, demonstrated abnormally low blood flow in virtually every area of the brain studies in nearly 1,000 marijuana compared to healthy controls..."

http://www.j-alz.com/content/new-study-shows-marijuana-users-have-low-blood-flow-brain

27 November 2016 Hippocampus, the brain’s key memory and learning center, has the lowest blood flow in marijuana users suggesting higher vulnerability to Alzheimer’s Costa Mesa, CA - As the U.S. races to legalize marijuana for medicinal and recreational use, a new, large scale brain imaging study gi...