Scientists at FAU and their colleagues in Spain have discovered that astrocytes in the prefrontal cortex (PFC) play an important role in the brain in goal-directed behaviour when weighing up the advantages and disadvantages of a decision. They have recently published their findings in the journal Nature Neuroscience.
Up to now, scientists have often presumed that only neurons, which are the cells responsible for carrying electrical impulses in the brain, play a role in decision-making processes. However, a collaborative project involving the laboratories of Prof. Dr. Alexey Ponomarenko, Professorship for Physiology at FAU, and Dr. Gertrudis Perea from the Cajal Institute in Madrid, Spain in partnership with the New York University Langone Medical Center, has now proven that astrocytes play the central role in decision making. Astrocytes are a type of glial cell, which form the scaffolding for nerve cells. Experiments conducted by the study’s lead author, Dr. Sara Mederos, demonstrated that the star-shaped cells in the prefrontal cortex generate the balance required between signal transmitting neurons and inactive neurons. This equilibrium needs to be in place for the brain to make decisions quickly and successfully.
The researchers also discovered that astrocytes react to neurotransmitter signals in the brain which neural networks need to transmit signals to each other. Specifically, astrocytes respond to the inhibiting neurotransmitter GABA. Experiments with mice in the laboratory showed that the mice made better decisions when the neurotransmitter in the astrocytes positively influenced rapid gamma oscillation. Brain oscillation is a type of internal timekeeper for neuron activity, as it sets the rhythm at which cells function. When the research team used light impulses to increasingly stimulate astrocytes, this improved the gamma oscillation and thus the overall cognitive performance. Optogenetics is a proven technique for making cells sensitive to light by means of genetic modification. Scientists are then able to stimulate these cells using light.
The research project showed that brain functions that depend on astrocytes can be improved using optogenetics which leads to quicker and more precise decisions. The effectiveness of brain oscillation modulation using light impulses is currently being investigated in several fields, for example in the treatment of Alzheimer’s. This research into the function of astrocytes will provide valuable input for practical applications.