Marijuana is a plant with psychoactive (mind-altering) properties that targets the central nervous system and alters the brain's ability to communicate between neurons, which is the body's information processing system. Although marijuana comes from a natural plant source, the potency of the drug significantly alters the way a normal brain functions. Tetrahydrocannabinol (THC) is the active ingredient in marijuana that highly affects the brain regions of the cerebellum, hippocampus, cerebral cortex, nucleus accumbens and basal ganglia. THC also moderately affects the hypothalamus, amygdala and brain stem.
Parts of the Brain Highly Affected
The THC in marijuana attaches to naturally produced cannabinoid receptors in the brain and changes how these receptors process information. The natural regulating mechanisms become blocked and produce an overflow of chemicals, causing the disruptions of regular brain functioning. Areas highly affected by the drug include the cerebellum and basal ganglia. These areas are responsible for movement, coordination, balance and body control. The cognitive system, including the hippocampus and cerebral cortex, are areas responsible for learning, memory and thinking. Cognitive functions are overloaded by THC during marijuana use and create lapses in thought process, time delay and loss of memory. Research further indicates that there are long-term affects to these areas of the brain when marijuana is used on a regular basis over time.
Parts of the Brain Moderately Affected
Marijuana use alters emotions, response time, arousal and perceptions of pain. Depending on quantity used, the THC can modify the hypothalamus' ability to regulate body functions such as temperature and reproductive function. The amygdala is the brain region responsible for emotional response; when someone is intoxicated on marijuana, this area of the brain tends to show slow or blunted reactions to situations that might normally produce fear or excitability. Pain receptors in the brain are also changed with marijuana use. In many cases, this could be perceived as a positive function of marijuana, however, it could also be unhealthy as the body will not respond to pain as it should in order to withdraw from the pain- stimulating source.
Brain Neurotransmitters Affected
The cannabinoid receptors are activated by neurotransmitters in the brain. The naturally occurring cannabinoids referred to as endocannabinoid ligands include anandamide, 2-arachidonoyl glycerol, N-arachidonoyl-dopamine, and virohamine. These cannabinoids are all similar in chemical makeup to the active ingredient in marijuana. However, when paired with THC from marijuana use, the natural neurotransmitters do not function in the same capacity and are unable to provide the correct information to the different brain regions in order for the body to respond in a normal manner to brain commands. The affect marijuana use has on the brain is a complex yet significant process that ultimately alters how the brain and body will function for a person over time.