In addition, such a localizationist approach implicitly resulted in the enduring principle of a similar brain functional anatomy across individuals, as for example the Broca's area that has been a priori considered to the output speech area in all human brains. According to this rigid paradigmatic framework, the brain anatomo-functional organization consists of highly specialized eloquent regions (such as Rolandic and Wernicke’s areas) for which any insult necessarily leads to persistent neurological impairments, as opposed to “noneloquent” structures for which no functional consequences occur in the event of injury. The first part will review the traditional, and still deeply rooted, localizationist model in which one discrete brain area corresponds to one specific function (the so-called one-to-one mapping). Therefore, this paradigmatic shift in modeling the functional anatomy of the central nervous system, from a rigid and localized framework to a flexible and highly distributed organization, has many applications, both in basic neurosciences and clinical neurology. This meta-network functioning also provides a great deal of flexibility into the anatomo-functional architecture, allowing cognitive resilience and functional compensation in brain-damaged patients, provided that brain structures involved in within and between-network communication are preserved (e.g., connective tracts). In addition, the interactions between such distributed subcircuits, capable of reshaping over time, open the door to a huge potential for neuroplasticity, which plays a pivotal role in learning and ontogeny.
Here, the purpose is to review new findings on the neural networks mediating ‟basicˮ brain functions such as action, visuospatial cognition, or language and on how the dynamic interactions between these specialized functional systems lead to high-level cognitive functions and flexible behaviors. According to this more realistic model, complex cognitions and goal-directed behaviors arise from the spatiotemporal integration of parallel and interconnected large-scale distributed networks. Recent data gained from functional neuroimaging and direct electrical stimulation of the central nervous system (CNS) challenged this purely modular theory and allowed to progressively shift towards a connectomal account of cerebral processing. We discuss the major implications of this approach in fundamental neurosciences as well as for clinical developments, especially in neurology, psychiatry, neurorehabilitation, and restorative neurosurgery.įor a long time, brain processes were mainly thought in a localizationist way of thinking. Indeed, a meta-networking organization underlies the uniquely human propensity to learn complex abilities, and also explains how postlesional reshaping can lead to some degrees of functional compensation in brain-damaged patients. Dynamic interactions between such circuits result in a perpetual succession of new equilibrium states, opening the door to considerable interindividual behavioral variability and to neuroplastic phenomena.
This model holds that complex cognitions and behaviors arise from the spatiotemporal integration of distributed but relatively specialized networks underlying conation and cognition (e.g., language, spatial cognition). Based on these recent data on brain connectome, we challenge the traditional, outdated localizationist view and propose an alternative meta-networking theory. Here, we review recent findings gained from neuroimaging, electrophysiological, as well as lesion studies. However, advances in brain mapping techniques in humans have provided new insights into the organizational principles of anatomo-functional architecture. For more than one century, brain processing was mainly thought in a localizationist framework, in which one given function was underpinned by a discrete, isolated cortical area, and with a similar cerebral organization across individuals.
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