The neocortex is involved in higher order function such as conscious thinking and activating the movement of muscles. Yet, the structure of the neural networks within the neocortex has remained a mystery to scientists. Now a team at University of Southern California were able to label over 600 neuronal pathways within the neocortex of a mouse using tracer injections. A fluorescent compound was injected into the cortex, the movement of which the team followed under a microscope, tracing out the neuronal network. This allowed them to create a logical structure of the neocortex, revealing eight subnetworks, each with a unique topology.
The team claims this is the most detailed mapping of the most advanced region of the brain.
From the study abstract:
A total of 240 intracortical connections were manually reconstructed within a common neuroanatomic framework, forming a cortico-cortical connectivity map that facilitates comparison of connections from different cortical targets. Connectivity matrices were generated to provide an overview of all intracortical connections and subnetwork clusterings. The connectivity matrices and cortical map revealed that the entire cortex is organized into four somatic sensorimotor, two medial, and two lateral subnetworks that display unique topologies and can interact through select cortical areas. Together, these data provide a resource that can be used to further investigate cortical networks and their corresponding functions.
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