Edinburgh Imaging

MSc projects 1011 001

The role of the cerebellum in attention: an fMRI-DTI study.

  • Background: In the last 3 decades, controversial discussions on the role of the cerebellum in higher cognitive functions have taken place. After the description of Schmahmann, in 1998, of the cerebellar cognitive affective syndrome, more researchers have begun to examine the role of the cerebellum in higher cognitive functions. Attention tasks have been especially controversial, with diverging opinions on the function of the cerebellum and most of the published research showing cerebellar involvement are criticised because their experimental design could not distinguish between the role of the cerebellum in attention and its well known function in coordinating the motor outputs that are often used to index attentional performance (ie button press, eye movements). For the cerebellum to be involved in attention, a few criteria have to be met, and as such can be verified with different techniques. First there is the need for anatomical connection with the supratentorial regions involved in attention. Second they need to be active during the task. The regions can be directly connected, or else go through key regions such as the thalamus. These can be observed either with anatomical dissection, with viral tracers as well as with Diffusion Tensor Imaging (DTI) by tracking white matter. Since an anatomical connection alone doesn’t mean that the regions are actually recruited during the task; we have to monitor those areas of the cerebellum to see if they are active during the task. Functional MRI (fMRI) provides the answer as to whether the regions are activated during a task involving attention.

    One final aspect that cannot be answered with a functional study is whether these areas are essential within the “attentional” network. This could only be answered by looking at lesional studies, and with neural disruption techniques such as TMS, which are beyond the scope of this project. The aim of this project was to study the anatomical network in the cerebellum that might be involved in attention. An imaging study was designed with a combination of fMRI and DTI to study this; focussing here on the DTI study.

  • Methods: 9 subjects healthy volunteers were recruited. They underwent an anatomical MRI, a diffusion-weighted sequence as well as fMRI tasks looking at covert attention. Regions of interest (ROI) were selected on the basis of fMRI activations and used as seed regions for the DTI.
  • Results: Fractional Anisotropy (FA) values were obtained at the different ROIs. The connections between different ROI were variable between subjects. There also was variability in the correlation between FA values in different regions of the brain.
  • Conclusion: While this is a pilot study with a relatively small number of subjects, and further analysis of the data would be required, this study is still important since it does show an involvement of the cerebellum in visual attention tasks by the activation of cerebellar regions during the fMRI as well as the anatomical connectivity between those regions.
Project type:
  • Data acquisition & analysis
Imaging keywords:
Application / disease keywords:
  • Cerebellar cognitive affective syndrome
  • 10-11