Abstract
Previous studies reported abnormal spontaneous neural activity in Parkinson’s disease (PD) patients using resting-state functional magnetic resonance imaging (R-fMRI). However, the frequency-dependent neural activity in PD is largely unknown. Here, 35 PD patients and 35 age- and education-matched healthy controls (HCs) underwent R-fMRI scanning to investigate abnormal spontaneous neural activity of PD using the amplitude of low-frequency fluctuation (ALFF) approach within the conventional band (typical band: 0.01–0.08 Hz) and specific frequency bands (slow-5: 0.010–0.027 Hz and slow-4: 0.027–0.073 Hz). Compared with HCs, PD patients exhibited increased ALFF in the parieto-temporo-occipital regions, such as the bilateral inferior temporal gyrus/fusiform gyrus (ITG/FG) and left angular gyrus/posterior middle temporal gyrus (AG/pMTG), and displayed decreased ALFF in the left cerebellum, right precuneus, and left postcentral gyrus/supramarginal gyrus (PostC/SMG) in the typical band. PD patients showed greater increased ALFF in the left caudate/putamen, left anterior cingulate cortex/medial superior frontal gyrus (ACC/mSFG), left middle cingulate cortex (MCC), right ITG, and left hippocampus, along with greater decreased ALFF in the left pallidum in the slow-5 band, whereas greater increased ALFF in the left ITG/FG/hippocampus accompanied by greater decreased ALFF in the precentral gyrus/PostC was found in the slow-4 band (uncorrected). Additionally, the left caudate/putamen was positively correlated with levodopa equivalent daily dose (LEDD), Hoehn and Yahr (HY) stage, and disease duration. Our results suggest that PD is related to widespread abnormal brain activities and that the abnormalities of ALFF in PD are associated with specific frequency bands. Future studies should take frequency band effects into account when examining spontaneous neural activity in PD.
Highlights
As one of the most common neurodegenerative disorders, Parkinson’s disease (PD) is characterized by motor symptoms, such as resting tremor, bradykinesia, rigidity, postural instability, and non-motor symptoms, including autonomic dysfunction, mood disorders, and cognitive impairments (Herrington et al, 2017)
We investigated the altered amplitude of low-frequency fluctuation (ALFF) of PD patients in the onmedication state in the typical band (0.01–0.08 Hz) and further in specific frequency bands
A study of PD with hallucination (Yao et al, 2015) in the “on” state found that PD patients with or without hallucination exhibited similar increased ALFF in the medial temporal lobe and temporo-parietal gyrus compared with healthy controls (HCs), which was consistent with our results
Summary
As one of the most common neurodegenerative disorders, Parkinson’s disease (PD) is characterized by motor symptoms, such as resting tremor, bradykinesia, rigidity, postural instability, and non-motor symptoms, including autonomic dysfunction, mood disorders, and cognitive impairments (Herrington et al, 2017). Resting-state functional magnetic resonance imaging (R-fMRI) reveals the phenomenon of spontaneous neuronal activity at rest by examining spontaneous fluctuations of the blood oxygen leveldependent (BOLD) signal, providing a reliable measure of baseline brain activity (Gusnard et al, 2001; Fox and Raichle, 2007; Liu et al, 2013). As a reliable measure of the magnitude of spontaneous BOLD signals, the amplitude of low-frequency fluctuations (ALFF) has been widely applied to assess spontaneous neural activity related to cerebral physiological and pathological states (Skidmore et al, 2013; Zhang et al, 2015; Wang et al, 2016). Tang et al (2017) reported decreased ALFF in the bilateral lingual gyrus and left putamen in PD patients compared with healthy controls. A meta-analysis (Pan et al, 2017) reported that the most consistent and replicable findings in PD patients were decreased ALFF in the bilateral supplementary motor areas, left putamen, left premotor cortex, and left inferior parietal gyrus and increased ALFF in the right inferior parietal gyrus
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