How messenger substances influence individual decision-making

February 10, 2021

As indicated by other studies, different parts of the brain are responsible for different types of decisions. A research team led by Luca Franziska Kaiser and Prof. Dr. Gerhard Jocham from the HHU working group 'Biological Psychology of Decision Making', and Dr. Theo Gruendler together with colleagues in Magdeburg analysed the balance of the messenger substances GABA and glutamate in two forms of decision-making. The background to the research was to find out how different concentrations of these substances influence the person making the decision.

On the one hand, the researchers looked at 'reward-based decisions', which involve maximising reward by selecting the better of two current options. Luca Kaiser gives a simple example: "Where do I buy coffee on my way to work, depending on the price, quality and whether or not the café is on my way?" Previous results suggest that such decision-making processes in the brain are mainly processed in the ventromedial prefrontal cortex (vmPFC).

'Patch-leaving decisions' are about long-term strategic issues that include an extensive balancing of cost against gain. An example of such a decision would be whether to move from Düsseldorf to Munich for a job offer. Prof. Jocham explains: "The job in Munich may offer a higher salary and a more interesting role, but may also involve stress and the effort involved in finding a place to live and moving to Munich as well as higher rents and the loss of social contacts in Düsseldorf." So there are many factors that influence this type of decision. According to the literature, such decisions are made in the brain's dorsal anterior cingulate cortex, or dACC for short.

The two messenger substances glutamate and GABA play a key role, and the ratio between the two determines the 'E/I balance' between excitatory and inhibitory transmission activity. The researchers used magnetic resonance spectroscopy to measure the concentrations of GABA and glutamate in different cortical areas of different subjects.

The team then used the data to correlate the ratio of the two messenger substances with the individual decision-making behaviour of the subjects. In the patch-leaving scenario, subjects with a higher ratio of GABA to glutamate in dACC were quicker to leave a depleting resource. By contrast, people with higher concentrations of glutamate needed a greater quality improvement before deciding to leave their current patch.

In the other scenario, subjects with higher concentrations of GABA relative to glutamate in vmPFC exhibited significantly increased decision accuracy. They were more reliable at selecting the higher-value option.

Luca Kaiser says: "Our results show a correlation between decision-making behaviour and the balance of two messenger substances in the brain. People with a higher ratio of excitation to inhibition in dACC need more of an incentive to move away from their status quo. By contrast, people with more GABA in vmPFC exhibit greater accuracy for short-term decisions."
Original publication

Kaiser LF, Gruendler TOJ, Speck O, Luettgau L, Jocham G (2021) Dissociable roles of cortical excitation-inhibition balance during patch-leaving versus value-guided decisions, Nature Communications

DOI: 10.1038/S41467-020-20875-W

Heinrich-Heine University Duesseldorf

Related Brain Articles from Brightsurf:

Glioblastoma nanomedicine crosses into brain in mice, eradicates recurring brain cancer
A new synthetic protein nanoparticle capable of slipping past the nearly impermeable blood-brain barrier in mice could deliver cancer-killing drugs directly to malignant brain tumors, new research from the University of Michigan shows.

Children with asymptomatic brain bleeds as newborns show normal brain development at age 2
A study by UNC researchers finds that neurodevelopmental scores and gray matter volumes at age two years did not differ between children who had MRI-confirmed asymptomatic subdural hemorrhages when they were neonates, compared to children with no history of subdural hemorrhage.

New model of human brain 'conversations' could inform research on brain disease, cognition
A team of Indiana University neuroscientists has built a new model of human brain networks that sheds light on how the brain functions.

Human brain size gene triggers bigger brain in monkeys
Dresden and Japanese researchers show that a human-specific gene causes a larger neocortex in the common marmoset, a non-human primate.

Unique insight into development of the human brain: Model of the early embryonic brain
Stem cell researchers from the University of Copenhagen have designed a model of an early embryonic brain.

An optical brain-to-brain interface supports information exchange for locomotion control
Chinese researchers established an optical BtBI that supports rapid information transmission for precise locomotion control, thus providing a proof-of-principle demonstration of fast BtBI for real-time behavioral control.

Transplanting human nerve cells into a mouse brain reveals how they wire into brain circuits
A team of researchers led by Pierre Vanderhaeghen and Vincent Bonin (VIB-KU Leuven, Université libre de Bruxelles and NERF) showed how human nerve cells can develop at their own pace, and form highly precise connections with the surrounding mouse brain cells.

Brain scans reveal how the human brain compensates when one hemisphere is removed
Researchers studying six adults who had one of their brain hemispheres removed during childhood to reduce epileptic seizures found that the remaining half of the brain formed unusually strong connections between different functional brain networks, which potentially help the body to function as if the brain were intact.

Alcohol byproduct contributes to brain chemistry changes in specific brain regions
Study of mouse models provides clear implications for new targets to treat alcohol use disorder and fetal alcohol syndrome.

Scientists predict the areas of the brain to stimulate transitions between different brain states
Using a computer model of the brain, Gustavo Deco, director of the Center for Brain and Cognition, and Josephine Cruzat, a member of his team, together with a group of international collaborators, have developed an innovative method published in Proceedings of the National Academy of Sciences on Sept.

Read More: Brain News and Brain Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to