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The link between structural connectivity and neurocognition illustrated by focal epilepsy Volume 20, numéro 2, April 2018

TEST YOURSELF

(1) What is an “hodological model”?

(2) What does the term “minimal subcortical plasticity” mean?

(3) With respect to the nature and degree of white matter alteration as a result of epileptic activity, explain the theory of initiation.

 

 

 

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Answers

(1) Recent neurocognitive models integrate structural connectivity in addition to functional data and are based on the conception that cerebral processing results from the integration of both function and anatomy of cerebral networks. Hodological models have emerged due to the strong correlation between WM structural properties and cognitive aspects. In the particular case of focal epilepsy, considered as a network disorder, the development of hodological models provides a more complete picture of reorganization patterns induced by pathology, as well as their behavioural consequences.

(2) This notion refers to the fact that the white matter macrostructure is not susceptible to significant reorganisation and shows only weak inter-individual variability. Indeed, its wiring is practically identical in all individuals. Overall, at a macroscopic level, white matter does not have compensatory capability in cases of lesions. However, its microstructure shows high plastic potential, closely related to brain functioning, thus offering the possibility to disentangle areas with efficient as opposed to less efficient functioning.

 (3) According to the theory of initiation, although white matter abnormalities are diffuse and generalized across hemispheres, they are variable in terms of nature and intensity (cf. centrifugal decrease; the result of an indirect effect of epileptic seizures on distant fibres). If future studies robustly support this theory, some structural connectivity parameters could be defined to help pinpoint, with better accuracy, the epileptic zone before surgery.

 

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