Research group offers new insights into the roles of different subareas in the prefrontal cortex
Whether the brain responds to an external stimulus or not depends significantly on the balance between areas of excitation and inhibition in the prefrontal cortex (PFC). Synaptic connections in the front of the cerebral cortex enable the brain to make a conscious decision on whether to react to a stimulus with movement or not.
However, the roles of the individual regions in the PFC and how they work together in this decision-making process were unknown until now. An international team led by Stefanie Hardung from the research group of Professor Ilka Diester, a member of Bernstein Center Freiburg and the Cluster of Excellence BrainLinks-BrainTools, has now identified the roles five subareas in the prefrontal cortex play in making decisions on movement. Their results were now published in the journal Current Biology. This study may be of particular significance for the further investigation of impulse control disorders.
“We might compare these regions of the prefrontal cortex with a traffic light,” says Stefanie Hardung. “Specific subareas of the PFC are responsible for inhibition, while others take care of movement preparation and excitation.” In their experiment, the researchers employed a framework in which they trained transgenic rats in proactive and reactive stopping: “Reactive stopping refers to a situation in which the animal stops in reaction to an external signal. Proactive stopping, on the other hand, develops according to the internal goals of the subject.”
In their specific setup, the rats were trained to press a lever and to stop if a specific signal was given. Another signal indicated that the rat was supposed to keep pressing the lever. With the help of optogenetics, the research group was able to deactivate specific genetically altered brain cells using light. The scientists systematically switched off certain subareas of the PFC to test the influence of these respective regions on the decision-making process. In addition, optogenetics enabled the group to compare the results with the behavior of the same animals when all areas were intact.
The deactivation of specific PFC regions significantly altered the performance of the animals: The inhibition of regions in the infralimbic cortex (IL) or the orbitofrontal cortex (OFC) impeded the ability of the rats to react to external signals.
Deactivation of the prelimbic cortex (PL), on the other hand, caused a premature reaction in the majority of the rats. Furthermore, the researchers employed electrophysiological measuring methods and observed that neuronal activity in the PL significantly decreased prior to the premature reactions when all regions were intact.
These insights support the hypothesis that the infralimbic cortex and the prelimbic cortex play an opposing role to that of the orbitofrontal cortex: While the IL and the PL direct proactive behavior in reaction to external signals, the OFC controls reactive behavior. Thus, their study might serve as a basis for new approaches in the investigation of impulse control disorders such as attention deficit hyperactivity disorder (ADHD) or obsessive-compulsive disorders (OCD).
“Optogenetic approaches are less harmful to the animals than surgical or pharmacological interventions,” Hartung explains. “They allow us to deactivate different brain areas swiftly and reversibly without affecting circuit connectivity. Thus, our animal model might serve as an adequate framework for investigating impulse control disorders.”
Bernstein Center Freiburg
University of Freiburg
Phone: +49 (0)761/203-9322
Cluster of Excellence BrainLinks-BrainTools
University of Freiburg
Phone: +49 (0)761/203-67721
Rudolf-Werner Dreier | Albert-Ludwigs-Universität Freiburg im Breisgau
ADP-ribosylation on the right track
26.04.2018 | Max-Planck-Institut für Biologie des Alterns
Flavins keep a handy helper in their pocket
25.04.2018 | University of Freiburg
Magnetic resonance imaging, or MRI, is a widely used medical tool for taking pictures of the insides of our body. One way to make MRI scans easier to read is...
At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.
Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
26.04.2018 | Medical Engineering
26.04.2018 | Power and Electrical Engineering
26.04.2018 | Information Technology