Neural activation and radial diffusivity in schizophrenia: combined fMRI and diffusion tensor imaging study.

Background: Schizophrenia is associated with often widespread changes in white matter structure. Most studies have investigated changes in fractional anisotropy, whereas alterations in radial or axial diffusivity have barely been investigated until now.

Aims: To investigate radial diffusivity as a potential marker of dysmyelination in direct relation to abnormalities in neural activation.

Method: Neural activation in association with decision-making under uncertainty was investigated in 19 people with schizophrenia and 20 healthy controls and linked to radial diffusivity as measured by diffusion tensor imaging.

Results: Decision-making under uncertainty was associated with a significantly decreased activation in a frontostriatocingulate network in the schizophrenia group. Structurally, they exhibited increased radial diffusivity in temporal white matter that was negatively correlated with activation in parts of the frontostriatocingulate network.

Conclusions: Present data indicate that altered diffusivity within relevant white matter networks may be closely linked to abnormal neural activation in schizophrenia.