Data from: Substantia nigra integrity correlates with sequential working memory in Parkinson’s disease

Maintaining and manipulating sequential information online is essential
for daily activities such as planning. In Parkinson’s disease (PD),
deficits in sequential working memory have been associated with altered
regional activation and functional connectivity within the basal ganglia.
This study demonstrated that the substantia nigra (SN) integrity
correlates with basal ganglia dysfunction during sequential working
memory. We included 29 patients with PD and 29 healthy controls (HC). We
assessed the SN integrity using neuromelanin-sensitive MRI and sequential
working memory using functional MRI and a digit ordering task. In this
task, participants either recalled a sequence of digits in the original
order (‘pure recall’) or rearranged the digits in ascending order and
recalled the new sequence (‘reorder & recall’). PD showed smaller
SN areas than HC, especially on the left side. Compared to HC, PD showed
lower task accuracy, hyper-activation of the subthalamic nucleus,
hypo-activation of the caudate nucleus and globus pallidus, and weakened
functional connectivity between the bilateral SN and all three basal
ganglia regions. Moreover, PD showed distinct brain-behavior and
structure-function relationships. Ordering-related accuracy cost (‘reorder
& recall’ versus ‘pure recall’) correlated with the
ordering-related subthalamic activation in HC, but with the
ordering-related caudate activation in PD. In PD, the caudate activation
correlated with the total SN area, whereas the subthalamic activation
correlated with daily exposure to D2/3 receptor agonists. In conclusion,
damage to the SN may lead to basal ganglia dysfunction sequential working
memory deficits even in early PD.