Hello, I hope that you had a great weekend.
Today's episode is on neurotransmitters.
For me, this is where we start to get into ‘proper’ biology because this chapter and the next chapter which is on hormones are vital forces behind various behaviours.
Let me explain…
Neurotransmitters are chemical messengers that are released into the synaptic gap; the space in between two neurons.
Now I could go into the more complex dynamics of how a neuron work and how a neurotransmitter is used, and I could go into this at depth.
However, the point of this book is to explain concepts simply so that’s what I’ll do.
Therefore, transferring information in a neuron is partly chemical and electrical.
The electrical part comes from the electrical impulse that moves the information through the neuron.
When it gets to the end of the neuron where the synapse is a neurotransmitter gets released and then the neurotransmitter diffuses (moves) across the gap and then it gets absorbed by the other neuron. Or it can get reabsorbed into the neuron it was released from. This is called reuptake.
Crockett et al (2010)
Our first study looks at the effects of serotonin; a neurotransmitter responsible for our mood and sleep cycle; on good social behaviour.
In this experiment, the researchers got 30 healthy volunteers and split them into two groups. The first group was given a dose of citalopram. Which is a Selective Serotonin Reuptake Inhibitor. (SSRI) This meant that the neuron that released the serotonin couldn’t reabsorb it. This, in turn, boosted its concentration in the synaptic gap and prolonged its effects.
Then the second group was given a placebo; a chemical they thought was the SSRI, but it wasn’t.
Afterwards, the two groups were given the ‘Trolley Problem’ this is a scenario where you are given the choice of interfering or doing nothing to stop a runaway trolley from killing five people.
Although, the two groups were given two scenarios. In the first; the Impersonal Scenario; they could pull a lever, and this would put the trolley on another track, and this would kill one person.
In the second; the personal scenario; the participant could actively choose to push a man off a bridge to save the five men.
In both of these situations the choice is to kill one man to save five, but in the personal situation, the choice of killing is more direct and more emotionally aversive as an act.
The results for the two groups shown no differences in the choices for the impersonal situation.
Although in the personal situations the people that were given the citalopram were less likely to interfere and push the man off the bridge.
In conclusion, citalopram reduces the acceptability of personal harm to people. This is in a sense promotes good social behaviour (prosocial behaviour) so increased levels of serotonin may cause people to be more opposed to the idea of inflicting harm to another.
Overall, this study shows that neurotransmitters affect our behaviour as this can promote prosocial behaviour.
The study was well controlled as it has a group that was given a placebo, so it was clear if the experimental group; which was the group given the SSRI; was affected by the citalopram. As you can compare the effects of the SSRIs against the placebo group.
On the other hand, the dose given to the participants was higher than in the bloodstream, but with there being over 100 different neurotransmitters in the body. How can we say that serotonin is the neurotransmitter responsible? Or could it be a mixture of several?
Fisher, Aron and Brown (2005)
In this experiment, they got 17 people who reported themselves as ‘intensely in love’ and did a brain scan on them in an fMRI (functional Magnetic Resonance Imaging- further information in the last chapter) and got them to do some tasks.
Firstly, the participants got to look at a photo of a loved one for 30 seconds, then for 40 seconds they were required to count back from a number, for the next 30 seconds they got to look at an image of an emotionally neutral friend and for the last 20 seconds, they counted back again. They repeated this six times for a total of 720 seconds.
The results showed that when looking at the photo of the loved one there was increased activity in the dopamine; a neurotransmitter involved in the feelings of romantic love; rich areas of the brain. More specifically in the Ventral Tegmental Area which is apart of the so-called dopaminergic pathway. This is a reward system for pleasure and motivation in the brain.
In conclusion, the neurotransmitter dopamine is involved in the feelings of romantic love.
So next time you go to kiss or hug your partner think of all that dopamine being released.
The study was effectively designed so that the counting back exercise allowed the brain’s activity to go back to ‘normal’ before the showing of each type of photo. Thus, this allowed the increase in brain activity to be clearly linked to the type of photo being shown.
Nevertheless, how can we be sure that those dopamine-rich areas of the brain only release dopamine? Is it possible that they release smaller amounts of other neurotransmitters and it’s, in fact, the combination of this cocktail that creates the feelings of romantic love?
What do you think?
Overall, neurotransmitter can affect behaviour for many reasons. For instance: they can increase prosocial behaviour, or they can make us feel romantically in love with someone.
A neurotransmitter is a chemical messenger released into the synaptic gap.
Crockett et al (2010) shows that serotonin promotes prosocial behaviour.
Fisher, Aron and Brown (2005) shows that dopamine does play a role in the feelings of love.
Overall, neurotransmitters do have a number of effects on human behaviour.
I hope that you enjoyed today's episode.
If you want to know more information about biological psychological then please heck out my book: Biological Psychology which you can get for FREE when you sign up for my mailing list.
Have a great week everyone.
Kind regards Connor.