Segregation And Integration In The Brain
The networks of the cerebral cortex exhibit two main principles of structural and functional organization, segregation and integration . Anatomical and functional segregation refers to the existence of specialized neurons and brain areas, often organized into distinct neuronal populations (groups or columns) or cortical areas. These specialized and segregated sets of neurons selectively respond to specific input features (such as orientation, spatial frequency, or wavelength), or conjunctions of features (such as faces). They reside in cortical areas that process separate feature dimensions (such as color and motion) or sensory modalities.
However, segregated and specialized neuronal units do not operate in isolation. There is abundant evidence that coherent perceptual and cognitive states require the coordinated activation, that is, the functional integration, of very large numbers of neurons within the distributed system of the cerebral cortex . Electrophysiological studies have shown that perceptual or cognitive states are associated with specific and highly dynamic (short-lasting) patterns of temporal correlations (functional connectivity) between different regions of the thalamocortical system . Human neuroimaging experiments have revealed that virtually all perceptual or cognitive tasks, for example, object recognition, memory encoding
and retrieval, reading, working memory, attentional processing, motor planning, and awareness, are the result of activity within large-scale and distributed brain networks.
- functional segregation in brains