When presenting on the brain, it becomes difficult to go into too much depth without bringing the basic neurotransmitters into the picture. Being much like electricity, neurotransmitters operate at such a minute level that we never really get to see how they work first hand. An analogy that works well (and is perhaps quasi-plagiarism from David Macaulay and his diagram above) is how I like to compare the neurotransmitters to components of a vehicle:
- This neurotransmitter is one of the most basic yet necessary transmitters. It is responsible for making decisions, motivation, reinforcement, as well as rewards. This is like the engine of the vehicle. It can be used to reward ourselves, and there are many critical decisions we need to make based on how well we know the engine.
- Addictions to certain levels of dopamine can lead to various addictions. If you become accustomed to driving while revving the engine between shifting gears, you may continue to do it for years to come. People who become accustomed to the high level of dopamine achieved through such acts as gambling and drug use at a young age (< 25 years old) can become addicted to that mode of keeping high dopamine levels for years to come. Much of this corresponds to dopamine predominantly having a significant role in the prefrontal cortex (PFC).
- The body will naturally raise dopamine levels through feelings of accomplishments and reaching goals. For this reason, having students/children set goals allows them to reach goals and release dopamine as a result.
- Many drugs used to treat ADHD do so through their primary function being that to increase the level of dopamine in the brain. With higher levels of dopamine, those with ADHD report being far more able to take time to reflect (an executive function in the PFC) and are less likely to make spontaneous decisions.
- Epinephrine is used interchangeably with its other name, adrenalin. This name is derived from the fact that epinephrine is primarily produced in the adrenal glands.
- Exercise causes a slight increase in the concentration of epinephrine in the body.
- While epinephrine can influence the emotional state in a number of ways, the emotion most strongly correlated to epinephrine is the negative state of fear.
- Increase in the level of epinephrine can lead to an increased ability with memory and consolidation of information.
- Epinephrine can be like the brakes of the vehicle. Brakes can be hovered over when there is fear, and some of our clearest memories can be experiences in which we were slamming on the brakes.
- The main focus of norepinephrine upon most organs is to prepare the organs for a higher degree of operation, and a greater rate of energy consumption.
- Norepinephrine is key in cardiovascular activity as it increases heart rate and glucose consumption by skeletal muscles.
- Over 90% of the body's norepinephrine is produced in a part of the brain stem, the pons.
- Many anti-depressants work to increase the concentration of norepinephrine by decreasing the rate at which the body degrades the norepinephrine into other chemicals.
- This is the fuel pump of the engine; without it we would have a lack of fuel reaching the engine.
Beginning to understand those three neurotransmitters is a key first step in understanding both how a healthy brain operates, but also what can be the origin for many disorders. Sometime in the near future I will give a brief explanation of one more neurotransmitter, serotonin, and two hormones that from many perspectives can be seen working much like neurotransmitters: melatonin and cortisol.