“Many of our daily decisions, such as the selection of a restaurant for a meal, are based on the recollection of relevant information from our memory. Until recently, however, the neuronal and cognitive mechanisms of such decisions had hardly been researched,” explains Prof. Dr. Christian Büchel, the director of the Institute for Systemic Neurosciences at the UKE. It is known that the hippocampus, a classic “memory region,” and the ventromedial prefrontal cortex in the frontal lobes, a “decision-making region,” are involved in these brain processes.
In the study, thirty young, and hungry test participants had to solve a task in which they first had to rate 48 snacks – such as potato chips and chocolate bars, salty snacks and chewing gum –based on their preferences. Afterwards, they were placed in a magnetic resonance scanner and had to choose repeatedly between two food offerings. The snacks were presented to them on a computer monitor in conjunction with certain locations. However, during the decision-making process they were only shown the locations, so that the test participants had to remember the associated snacks.
The result showed that the test participants tended to prefer snacks that they could remember better. What’s more: snacks that were better remembered were chosen even if they were comparatively unattractive, i.e. when the test participants initially gave them a low rating. The only snacks not chosen at all were those that had been strongly rejected by the respective test taker. In the comparison group, which was also comprised of 30 test participants, snacks were shown directly as an image – here, the initial rating usually matched with their subsequent choice.
The research group examined the neuronal mechanisms of memory-based decisions by utilizing functional magnetic resonance imaging (fMRI). They developed a mathematical model that illustrated the decision-making process, taking into consideration the influence of the memory. This allowed the scientists to determine the strength of the memory-based activation during storage in the hippocampus. An analysis of the activation during the decisions showed that an increased communication takes place between the hippocampus and the ventromedial prefrontal cortex.
“Our research constitutes a bridge between two central fields of research in psychology, the research of memory, and decision-making processes,” explains the initial author of the study, Dr. Sebastian Gluth, formerly of the Institute for Systemic Neurosciences at the UKE, now of the faculty for Psychology at the University of Basle. Furthermore, the combination of mathematical modeling and brain scans provides an accurate understanding of which areas of the brain are involved in which psychological sub-processes and how the various areas interact. The study was developed in cooperation with Dr. Tobias Sommer, and Prof. Dr. Christian Büchel, both also working at the Institute for Systemic Neurosciences at the UKE, and Prof. Jörg Rieskamp, of the faculty for Psychology at the University of Basle.
Sebastian Gluth, Tobias Sommer, Jörg Rieskamp, and Christian Büchel Effective connectivity between hippocampus and ventromedial prefrontal cortex controls preferential choices from memory, Neuron 2015, epub ahead of print. DOI: http://dx.doi.org/10.1016/j.neuron.2015.04.023
Prof. Dr. Christian Büchel
Institute for Systemic Neurosciences
Telephone: (040) 7410-54726