Groundbreaking Brain Maps Challenge Traditional Descriptions

Did not align with previous maps Her research group recorded and analysed the activity of more than 24,000 neurons in awake mice and created the first activity-based maps of the prefrontal cortex. The maps of spontaneous and cognition-related neuron activity did not match the traditional, tissue-based maps. “Our findings challenge the traditional way of defining brain regions and have major implications for understanding brain organisation overall,” says Marie Carlén. The researchers found that the activity patterns of neurons reflected the hierarchy of information flow in the brain rather than the structure of the tissue. Neurons with slow, regular activity turned out to be characteristic of the prefrontal cortex, which sits at the top of this hierarchy. The same activity pattern also marked regions at the top of the prefrontal cortex’s own internal hierarchy. Slow, regular activity is thought to characterise the integration of information flows, a process that is central to cognitive functions such as planning and reasoning. Different neuronal activity patterns work together Carlén and her colleagues discovered that neurons involved in decision-making were concentrated in regions high up in the prefrontal hierarchy. Surprisingly, these neurons were characterised by very fast activity patterns. “This suggests that cognitive processes rely on local collaboration between neurons whose activity patterns complement one another. Some neurons appear to specialise in integrating information streams, while others have high spontaneous activity that supports quick and flexible encoding of information, for instance, information needed to make a specific decision,” says Marie Carlén.” The study was funded by, among others, the Knut and Alice Wallenberg Foundation, the Wenner-Gren Foundation, and the Swedish Brain Foundation. Publication