Neural networks operate relatively independently of each other
29 June 2010
Neural networks (networks of neurons in the brain) operate relatively independently of each other. This is the conclusion of an international group of brain researchers, including clinical psychologist Renee Visser of the University of Amsterdam (UvA), in a recent article published in the scientific journal 'Proceedings of the National Academy of Sciences' (PNAS).
Neural networks (networks of neurons in the brain) operate relatively independently of each other. This is the conclusion of an international group of brain researchers, including clinical psychologist Renee Visser of the University of Amsterdam (UvA), in a recent article published in the scientific journal Proceedings of the National Academy of Sciences (PNAS). Using resting-state functional magnetic resonance imaging (rs-fMRI) they conducted research on patients with focal brain damage due to an ischemic stroke, a brain haemorrhage or an accident.
In their study the researchers made use of rs-fMRI with patients who had incurred heterogeneous brain damage to two networks which are important for cognitive control processes in the brain. With this relatively new form of functional MRI it is possible to see which patterns of functional relationships are visible between different areas of the brain (functional connectivity) without active task performance. The researchers examined to what extent the two damaged networks are independent of each other. The results show that the amount of damage to a network correlates with the extent to which communication between different areas within that network is disrupted. The disruption to functional connectivity between areas is also evident in the network outside the damaged area. Connectivity within other networks remains unaffected. This means that the functional consequences of anatomical damage are not solely restricted to the location of brain damage, but remain within the limits of the network where the damage has been incurred. As a result of these findings, researchers have proven that neural networks operate relatively independently of each other.
These findings contribute to both fundamental knowledge of connectivity in the brain as well as to a better understanding of clinical syndromes in people with cerebrovascular diseases or traumatic brain injuries. This explains why patients with damage to a particular area of the brain show some behavioural changes that are not directly attributable to what is known about the functions of that area. Knowledge of functional networks could help scientists anticipate similar behavioural changes more successfully in the future.
Emi M. Nomura, Caterina Gratton, Renée M. Visser, Andrew Kayser, Fernando Perez and Mark D'Esposito: ‘Double dissociation of two cognitive control networks In patients with focal brain lesions', Proceedings of the National Academy of Sciences (PNAS), June 2010.
The full article can be seen on the PNAS website. See the link below.