What if these were the very first brain networks that had just been identified by this team from the Max Planck Florida Institute for Neuroscience? These neuroscientists identify here, for the first time, a surprising spontaneous "network" activity in the immature brain, and these beginnings of local connections seem to provide a basis for the development of more sophisticated networks in the mature brain. Animal work presented in the journal Nature Neuroscience that helps explain how, in the cortex, individual neurons develop the first synaptic connections that will serve as the scaffolding for long-distance, very large-scale distributed networks in the brain adult.
The international team identifies and then establishes activity patterns generated spontaneously from local connections in the early developing visual cortex. These early activity patterns serve as a blueprint for the later development of long-range neural connections that characterize mature distributed networks.
Scientists from the Max Planck Institute for Neuroscience Florida, along with their colleagues from the Frankfurt Institute for Advanced Studies, Goethe University of Frankfurt and the University of Minnesota are deciphering the visual cortex of the ferret, an ideal model animal system for exploring the early development of networks in the cortex. These are composed of thousands of neurons and are distributed over only millimeters of cortical surface. In the visual cortex, network activity encodes specific features of the visual scene, such as boundary orientation and direction of object motion. Using advanced imaging techniques, scientists were able to visualize with unprecedented resolution patterns of spontaneous neuronal activity, that is, patterns of activity that occur in the absence of visual stimulation. In these models of spontaneous activity in mature animals, distant populations of neurons are found to be strongly connected to each other, to the point that the activity of small populations of neurons can reliably predict patterns of network activity. longer range. And these latter patterns appear to correspond to patterns of activity induced by visual stimulation, in the mature brain. activity of small populations of neurons can reliably predict longer-range network activity patterns. And these latter patterns appear to correspond to patterns of activity induced by visual stimulation, in the mature brain. activity of small populations of neurons can reliably predict longer-range network activity patterns. And these latter patterns appear to correspond to patterns of activity induced by visual stimulation, in the mature brain.
A remarkable correspondence between spontaneous network models and visually induced network models: this coincidence is obviously surprising and the scientists expected striking differences. But by examining the state of spontaneous activity patterns before the eyes open, they discover networks of spontaneous activity that span distances comparable to those seen in the mature brain. Using computer models, researchers realize and demonstrate that early short-range networks are the source of long-range networks in the early developing cortex.
Local connections create a scaffold for more extensive network activity in the cortex: the activity mediated by local connections somehow guides the subsequent formation of long-range network connections.
Think global, act local: the developing cortical circuits thus act locally to produce global effects.
Further research is underway to better understand the mechanisms of plasticity that allow the development of long-distance connections based on the activity patterns of local cortical connections .
