Unravelling the Alteration of Brain Structure and Function in Parkinson´s Disease With Ultra-high Field MRI

Parkinson's Disease (PD) is a neurodegenerative disease characterized by a range of disabling motor- and non-motor symptoms caused by a loss of neurons in neuromodulatory brainstem nuclei. Typical motor symptoms include bradykinesia, rigidity and tremor. Non-motor symptoms are diverse and include REM sleep behaviour disorder, hyposmia, autonomic dysfunction, depression, apathy and cognitive impairment. The motor symptoms can in some degree be attributed to degeneration of the substantia nigra (SN) and a deficiency of dopamine (DA) availability, and DA replacement therapy can partially alleviate motor symptoms. The role of nigral degeneration on non-motor symptoms is however less clear. In addition to nigral degeneration, the noradrenergic (NA) locus coeruleus (LC) also undergoes severe degeneration in PD. Again, it is unclear how LC degeneration contributes to motor and non-motor symptoms. Ultra-high resolution structural magnetic resonance imaging (MRI) provides the opportunity to assess alterations of the affected nuclei in detail and functional MRI (fMRI) can map activation in the neuronal populations as a measure of DA and NA function.