Researchers at the University of Freiburg Medical School and the Max Planck Institute for Brain Research have discovered the "zone of uncertainty" or "zona incerta" of the brain that communicates with the neocortex in unconventional ways and controls memory formation. It is the first study to analyze how long-range inhibition shapes information processing in the neocortex, which is largely responsible for memory formation and storage.
The brain connects “bottom-up” signals from the environmental stimuli and internally generated “top-down” signals that convey information about past experiences and current goals. This study focused on the mechanisms involved in top-down signals. Top-down projection systems share several common features, including signaling through synaptic excitation or sending information between cortical regions.
The study focused on a predominantly inhibitory subthalamic nucleus or the zona incerta, which sends inhibitory projections that impact regions of the neocortex involved in learning. The researchers tracked the responses of zona incerta synapses in the neocortex before, during, and after a learning paradigm. Study author Dr. Anna Schroeder described one key finding: “While about half of the synapses developed stronger positive responses during learning, the other half did exactly the opposite. In effect, what we observed was thus a complete redistribution of inhibition within the system due to learning.” This observation suggests that zona incerta synapses encode the learned relevance of sensory stimuli in a unique, bidirectional fashion. This research team also found a positive correlation between the magnitude of the bidirectional plasticity and the strength of the acquired memory.
Targeting the zona incerta for deep brain stimulation may lead to effective therapeutic treatments for a range of neurodegenerative conditions and anxiety disorders.
Sources: Eureka News Alert, Neuron, University of Frieburg
