When neurons in the frontal lobe are destroyed three things happen: the person wants fewer things, the person wants these things with greater intensity and the person will get bored faster. The effect of this on the environment is to deplete more of the same resources. How this happens will be shown here.
2 Dopamine receptors and the frontal lobe
The frontal lobe is responsible for the executive functions of the brain. When the frontal lobe is damaged, functions like motivation, planning, controlling emotions and making decisions, among others, are affected. (1) Dopamine is the neurotransmitter that is associated with reward, (2) and wanting. (3) It will be shown that dopamine receptors are in the frontal lobe by going through the functions that are affected when the frontal lobe is damaged and comparing them to the functions of dopamine. Functional changes associated with frontal lobe damage are explored here highlighting the role of dopamine.
The first function of dopamine is locomotion. (4) When the frontal lobe is damaged locomotion, or motor skills, are affected.
Another function of dopamine is memory, (5) something else that is affected when the frontal lobe is damaged.
Dopamine is known as 'the reward chemical' and when the frontal lobe is damaged problem=solving is affected, something where the reward is the solution to the problem.
Initiation is also rewarding or is something you want to do; the reason you initiate something is because you anticipate a reward.
Judgement is also associated with reward. When you make a choice, you are choosing the most rewarding option out of many, this is a cognitive process that we use every day.
The final one, impulse control, is also associated with reward. An impulse is a sudden strong and unreflective urge or desire to act., done because whatever that the impulse is will be rewarding.
Further evidence that dopamine receptors are in the frontal lobe is that the prefrontal lobotomy; a psychosurgical procedure. In which the connections to the prefrontal cortex, the anterior (front) part of the frontal lobe are scraped or severed away. Has been replaced by neuroleptic/ antipsychotic drugs such as Chlorpromazine (6) which block D2 dopamine receptors in the brain. This reinforces the inference that dopamine receptors are in the frontal lobe.
3 The effects of having a damaged frontal lobe
When neurons in the frontal lobe are destroyed, the affected person wants fewer things with greater intensity and they get bored faster, how this happens is explained here:
In a normal sized frontal lobe, there are a large amount of neurons which means that dopamine is spread widely across a large area and this corresponds to wanting many things with less intensity. In a damaged frontal lobe, there are fewer neurons so dopamine is concentrated into a smaller area, this corresponds to wanting fewer things with more intensity.
Another important effect of having a damaged frontal lobe is the person will get bored faster. (7) Although the exact mechanism of boredom is not known, it may be the process of down-regulation; a physical process which happens faster in damaged frontal lobes. Down-regulation is when receptors are recycled back into the neuron in response to neurotransmitters or hormones impacting the cell membrane. Which makes a neuron less responsive to future neurotransmitters or hormones. This process resembles boredom because what happens when you get bored is that you experience something pleasurable, chocolate for example, repeatedly until it fails to give you pleasure. In the same way, a neuron is impacted by a chemical messenger repeatedly which then makes that neuron less responsive in the future. This happens faster in damaged frontal lobes because the same number of chemical messengers are concentrated onto fewer cells.
However, a major limitation of this is that this is only the most likely explanation, meaning that down-regulation is only probably equivalent to boredom, and although we know for sure that frontal lobe damage does lead to boredom, we don’t know for sure that receptor down-regulation is boredom in the brain.
4 How frontal lobe damage harms the environment
When a person’s frontal lobe is damaged three important things happen: fewer things are wanted, they are wanted with greater intensity and the person gets bored faster. This is damaging to the environment because when somebody wants something physical, a motorcycle for example, they will get bored of it faster and look for something to give them pleasure. Since there are only a few things they want they will buy another motorcycle, because in their mind motorcycles are the most rewarding thing they can have.
If frontal lobe damage was absent then this person’s neurons will down-regulate slower or not at all and he will find his current collection of motorcycles rewarding for longer. This would remove his desire for another motorbike and prevent the subsequent damage to the environment. This is how frontal lobe damage harms the environment.
(1) Executive dysfunction | Headway. (2016). Headway.org.uk. Retrieved 4 November 2016, from https://www.headway.org.uk/about-brain-injury/individuals/effects-of-brain-injury/executive-dysfunction/
(2) Schultz, W. (2010). Dopamine signals for reward value and risk: basic and recent data. Behavioral And Brain Functions, 6(1), 24. http://dx.doi.org/10.1186/1744-9081-6-24
(3) Robinson, S., Sandstrom, S., Denenberg, V., & Palmiter, R. (2005). Distinguishing Whether Dopamine Regulates Liking, Wanting, and/or Learning About Rewards. Behavioral Neuroscience, 119(1), 5-15. http://dx.doi.org/10.1037/0735-7044.119.1.5
(4) Jaber, M., Robinson, S., Missale, C., & Caron, M. (1996). Dopamine receptors and brain function. Neuropharmacology, 35(11), 1503-1519. http://dx.doi.org/10.1016/s0028-3908(96)00100-1
(5) Sawaguchi, T. & Goldman-Rakic, P. (1991). D1 dopamine receptors in prefrontal cortex: involvement in working memory. Science, 251(4996), 947-950. http://dx.doi.org/10.1126/science.1825731
(6) The story of antipsychotics: Past and present. (2016). Indian Journal Of Psychiatry, 51(4), 324-326. Retrieved from http://www.indianjpsychiatry.org/article.asp?issn=0019-5545;year=2009;volume=51;issue=4;spage=324;epage=326;aulast=Ramachandraiah
(7) Goldberg, Y. & Danckert, J. (2013). Traumatic Brain Injury, Boredom and Depression. Behavioral Sciences, 3(3), 434-444. http://dx.doi.org/10.3390/bs3030434
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