Spontaneous neural activity in different frequency bands in Parkinson's disease: a fMRI study

Abstract

Objective To explore the pattern of spontaneous neural activity in different frequency bands in Parkinson's disease(PD). Methods The blood oxygen level-dependent signals in 39 PD patients and 37 normal controls were acquired and the amplitude of low-frequency fluctuation (ALFF) in five different frequecy bands (slow-2: 0.198-0.25 Hz; slow-3: 0.073-0.198 Hz; slow-4: 0.027-0.073 Hz; slow-5: 0.01-0.027 Hz; slow-6: 0-0.01Hz) was cacaulated. A repeated-measures analysis of variance and Post hoc t-test were performed to detect differences of spontaneous activity between two groups in different frequency bands. A correlation analysis was examined between Unified Parkinson’s Disease Rating Scale (UPDRS) motor score and ALFF in patients with PD in each frequency band to discover the relationship between disease severity and spontaneous neural activity. Results Compared with the normal controls, patients with PD had decreased ALFF in the putamen(-24, -3, -9) (-30, 3, 0)( -21, 9, 6)in the slow-3, slow-4 and slow-5, and had decreased ALFF in the left precentral gyrus (-21, -24, 75) (-21, -24, 72) (-27, -21, 72) (-15, -15, 72) and right supplementary motor area (21, -24, 75) (6, -3, 72) (12, -6, 60) (15, -24, 72) in all frequency bands except for the slow-5. Increased ALFF in the cerebellum was found in all frequency bands.The ALFF in the putamen was negatively correlated with the UPDRS motor score in the slow-3, slow-5 and slow-6. Conclusion This study shows that the abnormal activities in the striatum are significant in the slow-3, slow-4and slow-5. Most frequency bands except slow-5 are helpful in detecting neural changes in motor cortex. The increased activity in the cerebellum is the common findings in all frequency bands. Multiple frequency analysis may provide insight into the pathophysiological mechanisms of PD. Key words: Parkinson’s disease; Function MRI; Amplitude of low frequency fluctuation; Putumen