Neurotransmission and Behaviour
There are a number of different neurotransmitters. Research has shown that these different neurotransmitters are associated with particular behaviours. For instance:
- Dopamine: love, addiction, pleasure, motivation,
- Serotonin: mood, sleep, arousal, impulsive and aggressive behaviour
- Acetylcholine: learning, memory, sleep, movement
- Noradrenaline: stress, alertness arousal
There’s always a desire in students first learning about biological psychology to jump to making big, bold and erroneous statements like “serotonin controls our mood.” The verb “control” is a little too direct to use in this context. “Associated with” is a better phrase to use because it signifies the correlation between the two. We can’t say serotonin controls mood because what does that even mean? If we could increase serotonin levels in our brain would be happier or sadder? A complex behaviour like “mood” has more complex origins than the basic levels of serotonin in the brain. So while the research shows there’s a relationship there, the relationship is complex. Here we see again the importance of language in communicating your understanding.
So brain function refers to the level of activation of certain areas of the brain. Activation means that neurotransmission is occurring in a particular area of the brain. You don’t use 100% of your brain 100% of the time, so there’s actually an element of truth to the old adage “you only use 10% of your brain.” While it’s not as simple as that, the idea is the same: you use certain areas of your brain depending on the task you are doing. If you’re reading, for instance, you are using a different part of your brain than when you are listening or speaking.
Drugs affect neurotransmission and alter the levels of neurotransmitters in particular areas of the brain. This is what causes the various sensations and behaviour changes as a result of taking drugs. When one drinks alcohol, for instance, levels of dopamine in an area of the brain called the nucleus acumbens is increased. As this part of the brain is associated with pleasure and reward, the firing of dopamine between neurons throughout this part of the brain (also called the reward pathway) is why people feel happy and may get a sense of pleasure from drinking. This is just one example of how affecting the level of a neurotransmitter in the brain can have an impact on behaviour.
Travis Dixon is an IB Psychology teacher, author, workshop leader, examiner and IA moderator.