A new German study finds that women with a genetic predisposition for higher dopamine levels in the brain may be more likely to engage in procrastinating behaviors. No such link was found in men.
“The neurotransmitter dopamine has repeatedly been associated with increased cognitive flexibility in the past,” says Dr. Erhan Genç from the Ruhr-University Bochum Department of Biopsychology. “This is not fundamentally bad but is often accompanied by increased distractibility.”
The findings are published in the journal Social Cognitive and Affective Neuroscience.
The researchers studied the genotype of 278 men and women. They were particularly interested in what is known as the tyrosine hydroxylase gene (TH gene). Depending on the expression of the gene, people’s brains contain differing amounts of neurotransmitters from the catecholamine family, to which the neurotransmitter dopamine belongs, along with epinephrine (adrenaline) and norepinephrine (noradrenaline).
The team also used a questionnaire to record how well the participants were able to control their actions. They discovered that women with poorer action control had a genetic predisposition towards higher dopamine levels.
Whether an individual tends to postpone tasks or tackle them right away depends on his or her ability to maintain a specific intention to act without being distracted by interfering factors. Dopamine could be crucial here. In previous studies, dopamine has not only been associated with increased cognitive flexibility, but it also seems to make it easier for information to enter the working memory.
“We assume that this makes it more difficult to maintain a distinct intention to act,” says doctoral candidate Caroline Schlüter. “Women with a higher dopamine level as a result of their genotype may tend to postpone actions because they are more distracted by environmental and other factors.”
Previous research has also shown gender-specific differences between the expression of the TH gene and behavior.
“The relationship is not yet understood fully, but the female sex hormone oestrogen seems to play a role,” says Genç. Estrogen indirectly influences dopamine production in the brain and increases the number of certain neurons that respond to signals from the dopamine system.
“Women may therefore be more susceptible to genetic differences in dopamine levels due to oestrogen, which, in turn, is reflected in behaviour,” says the biopsychologist.
Next, the team intends to study to what extent estrogen levels actually influence the relationship between the TH gene and action control. “This would require taking a closer look at the menstrual cycle and the associated fluctuations in the participants’ oestrogen levels,” says Schlüter.
In addition to dopamine, the TH gene also influences norepinephrine, another important neurotransmitter from the catecholamine family. The researchers aim to examine the role that these two neurotransmitters play in action control in further studies.
Source: Ruhr-University Bochum