Summary: Women with higher levels of dopamine as a result of the TH gene tend to procrastinate more and are more distracted by their environment.
Some people tend to postpone actions. In women, this trait is associated with a genetic predisposition towards a higher level of dopamine in the brain. This is what researchers from Ruhr-Universität Bochum and the Technical University of Dresden discovered using genetic analyses and questionnaires. They were unable to identify this correlation in men. “The neurotransmitter dopamine has repeatedly been associated with increased cognitive flexibility in the past,” says Dr. Erhan Genç from the Bochum Department of Biopsychology. “This is not fundamentally bad but is often accompanied by increased distractibility.”
Erhan Genç reports on the results together with Caroline Schlüter, Dr. Marlies Pinnow, Professor Onur Güntürkün, Professor Christian Beste and associate professor (PD) Dr. Sebastian Ocklenburg in the journal Social Cognitive and Affective Neuroscience on 3 July 2019.
Only for women
The research group investigated 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. The team also used a questionnaire to record how well the participants were able to control their actions. Women with poorer action control had a genetic predisposition towards higher dopamine levels.
Dopamine and action control
Whether someone tends to postpone tasks or tackle them directly depends on the individual’s ability to maintain a specific intention to act without being distracted by interfering factors. Dopamine could be crucial here. In previous studies, the neurotransmitter has not only been associated with increased cognitive flexibility but 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.”
More susceptible to genetic differences?
Previous studies have revealed gender-specific differences between the expression of the TH gene and behavior. “The relationship is not yet understood fully, but the female sex hormone estrogen seems to play a role,” explains Erhan 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 estrogen, which, in turn, is reflected in behavior,” says the biopsychologist.
In future studies, the research team intends to investigate 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’ estrogen levels,” explains Caroline 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.
Caroline Schlüter – RUB
The image is in the public domain.
Original Research: Open access
“Genetic Variation in Dopamine Availability Modulates the Self-reported Level of Action Control in a Sex-dependent Manner”. Caroline Schlüter, Larissa Arning, Christoph Fraenz, Patrick Friedrich, Marlies Pinnow, Onur Güntürkün, Christian Beste Sebastian Ocklenburg Erhan Genc.
Social Cognitive and Affective Neuroscience. doi:10.1093/scan/nsz049
Genetic Variation in Dopamine Availability Modulates the Self-reported Level of Action Control in a Sex-dependent Manner
Although procrastination is a widespread phenomenon with significant influence on our personal and professional life, its genetic foundation is somewhat unknown. An important factor that influences our ability to tackle specific goals directly instead of putting them off is our ability to initiate cognitive-, motivational- and emotional-control mechanisms, so-called metacontrol. These metacontrol mechanisms have been frequently related to dopaminergic signaling. To gain deeper insight into the genetic components of procrastination, we examined whether genetically induced differences in the dopaminergic system are associated with interindividual differences in trait-like procrastination, measured as decision-related action control (AOD). Analyzing the data of 278 healthy adults we found a sex-dependent effect of TH genotype on AOD. Interestingly, only in women T-allele carriers showed lower AOD values and were, therefore, more likely to procrastinate. Additionally, we investigated whether differences in the morphology and functional connectivity of the amygdala that were previously associated with AOD happen to be related to differences in the TH genotype and thus to differences in the dopaminergic system. However, there was no significant amygdala volume or connectivity difference between the TH genotype groups. Therefore, this study is the first to suggest that genetic, anatomical and functional differences affect trait-like procrastination independently.