The brain encodes information collected by our senses. In order to perceive and interact with the environment, however, these sensory signals must be interpreted in the context of past experiences stored in the brain and the individual’s current aims. A team led by Prof. Dr. Johannes Letzkus, Professor at the Faculty of Medicine Faculty of the University of Freiburg and Research Group Leader at the Max Planck Institute for Brain Research in Frankfurt am Main, has now identified a key source of this experience-dependent so-called top-down information. The scientists have published their results in the journal Science.
The neocortex is the largest and most powerful area of the human brain. All of its important cognitive functions are made possible by the convergence of two distinct streams of information: a “bottom-up” stream, which represents signals from the environment, and a “top-down” stream, which transmits internally generated information about past experiences and current aims. The question of how and where exactly this internally generated information is processed is still largely unexplored, says Letzkus. This motivated him and his team to search for the sources of these top-down signals. The scientists succeeded in identifying a region of the thalamus, a brain area embedded deep within the forebrain, as a key candidate region for such internal information.