MJ slows down the brain’s ability to process information. The body then speeds up the flow of blood to the brain to try to compensate. With MJ the attempt to compensate does not bring the brain functions back up to the 100% level. Of course that is MJ. CBD with zero THC may speed up the blood flow, yet to what end?
The normally functioning brain consumes 20% to 25% of the body’s metabolic energy production. Blood flow is energy flow.