Rising superstar Rachael Grazioplene and colleagues focused on the cholinergic system— a biological system crucially involved in neural plasticity and learning. Situations that activate the cholinergic system involve “expected uncertainty” such as going to a new country you’ve never been before and knowing that you’re going to face things you’ve never faced before. This stands in contrast to “unexpected uncertainty”, which occurs when your expectations are violated, such as thinking you're going to a Las Vegas family friendly Cirque Di Soleil only to realize you’ve actually gotten a ticket to an all-male dance revue called "Thunder from Down Under" (I have no idea where that example came from). Those sorts of experiences are more strongly related to the neurotransmitter norepinephrine.
Since the cholinergic system is most active in situations when a person can predict that learning is possible, this makes the system a prime candidate for the differential susceptibility effect. As the researchers note, unpredictable and novel environments could function as either threats or incentive rewards. When the significance of the environment is uncertain, both caution and exploration are adaptive. Therefore, traits relating to anxiety or curiosity should be influenced by cholinergic genetic variants, with developmental experiences determining whether individuals find expected uncertainty either more threatening or more promising.
To test their hypothesis, they focused on a polymorphism in the CHRNA4 gene, which builds a certain kind of neural receptor that the neurotransmitter binds to. These acetylcholine receptors are distributed throughout the brain, and are especially involved in the functioning of dopamine in the striatum. Genetic differences in the CHRNA4 gene seem to change the sensitivity of the brain's acetylcholine system because small structural changes in these receptors make acetylcholine binding more or less likely. Previous studies have shown associations between variation in the CHRNA4 gene and neuroticism as well as laboratory tests of attention and working memory.
Individuals with the T/T variation of the CHRNA4 gene who were maltreated showed higher levels of anxiety (Neuroticism) compared to those with the C allele of this gene. They appeared to be more likely to learn anxious and fearful responses to situations with higher levels of uncertainty. In contrast, those with the T/T allele who were not maltreated were low in anxiety (Neuroticism) and high in curiosity (Openness to Experience). What’s more, this effect was independent of age, race, and sex. These results suggest that under normal parenting environments, the T/T allele (which is much rarer in the general population than the C allele) may be beneficial, bringing out lower levels of anxiety and increased curiosity in response to situations containing expected uncertainty.
- More Here and don't forgot to read David Dobbs brilliant 2009 piece The Science of Success
Since the cholinergic system is most active in situations when a person can predict that learning is possible, this makes the system a prime candidate for the differential susceptibility effect. As the researchers note, unpredictable and novel environments could function as either threats or incentive rewards. When the significance of the environment is uncertain, both caution and exploration are adaptive. Therefore, traits relating to anxiety or curiosity should be influenced by cholinergic genetic variants, with developmental experiences determining whether individuals find expected uncertainty either more threatening or more promising.
To test their hypothesis, they focused on a polymorphism in the CHRNA4 gene, which builds a certain kind of neural receptor that the neurotransmitter binds to. These acetylcholine receptors are distributed throughout the brain, and are especially involved in the functioning of dopamine in the striatum. Genetic differences in the CHRNA4 gene seem to change the sensitivity of the brain's acetylcholine system because small structural changes in these receptors make acetylcholine binding more or less likely. Previous studies have shown associations between variation in the CHRNA4 gene and neuroticism as well as laboratory tests of attention and working memory.
Individuals with the T/T variation of the CHRNA4 gene who were maltreated showed higher levels of anxiety (Neuroticism) compared to those with the C allele of this gene. They appeared to be more likely to learn anxious and fearful responses to situations with higher levels of uncertainty. In contrast, those with the T/T allele who were not maltreated were low in anxiety (Neuroticism) and high in curiosity (Openness to Experience). What’s more, this effect was independent of age, race, and sex. These results suggest that under normal parenting environments, the T/T allele (which is much rarer in the general population than the C allele) may be beneficial, bringing out lower levels of anxiety and increased curiosity in response to situations containing expected uncertainty.
- More Here and don't forgot to read David Dobbs brilliant 2009 piece The Science of Success
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