BACKGROUND: Cognitive impairment in Parkinson's disease (PD) is associated with altered connectivity of the resting state networks (RSNs). Longitudinal studies in well cognitively characterized PD subgroups are missing. OBJECTIVES: To assess changes of the whole-brain connectivity and between-network connectivity (BNC) of large-scale functional networks related to cognition in well characterized PD patients using a longitudinal study design and various analytical methods. METHODS: We explored the whole-brain connectivity and BNC of the frontoparietal control network (FPCN) and the default mode, dorsal attention, and visual networks in PD with normal cognition (PD-NC, n = 17) and mild cognitive impairment (PD-MCI, n = 22) as compared to 51 healthy controls (HC). We applied regions of interest-based, partial least squares, and graph theory based network analyses. The differences among groups were analyzed at baseline and at the one-year follow-up visit (37 HC, 23 PD all). RESULTS: The BNC of the FPCN and other RSNs was reduced, and the whole-brain analysis revealed increased characteristic path length and decreased average node strength, clustering coefficient, and global efficiency in PD-NC compared to HC. Values of all measures in PD-MCI were between that of HC and PD-NC. After one year, the BNC was further increased in the PD-all group; no changes were detected in HC. No cognitive domain z-scores deteriorated in either group. CONCLUSION: As compared to HC, PD-NC patients display a less efficient transfer of information globally and reduced BNC of the visual and frontoparietal control network. The BNC increases with time and MCI status, reflecting compensatory efforts.

• Klíčová slova
• Between-network connectivity, Parkinson’s disease, cognitive resting state brain networks, functional MRI, graph measures, longitudinal, mild cognitive impairment, partial least squares analysis,
• MeSH
• dospělí MeSH
• kognitivní dysfunkce etiologie   patologie   psychologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• longitudinální studie MeSH
• magnetická rezonanční tomografie MeSH
• mozek diagnostické zobrazování   patologie   MeSH
• nervová síť diagnostické zobrazování   patologie   MeSH
• neurozobrazování MeSH
• Parkinsonova nemoc komplikace   patologie   psychologie   MeSH
• prefrontální mozková kůra patologie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• temenní lalok patologie   MeSH
• testy pro posouzení mentálních funkcí a demence MeSH
• zrakové korové centrum patologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Visual processing difficulties are often present in Alzheimer's disease (AD), even in its pre-dementia phase (i.e. in mild cognitive impairment, MCI). The default mode network (DMN) modulates the brain connectivity depending on the specific cognitive demand, including visual processes. The aim of the present study was to analyze specific changes in connectivity of the posterior DMN node (i.e. the posterior cingulate cortex and precuneus, PCC/P) associated with visual processing in 17 MCI patients and 15 AD patients as compared to 18 healthy controls (HC) using functional magnetic resonance imaging. We used psychophysiological interaction (PPI) analysis to detect specific alterations in PCC connectivity associated with visual processing while controlling for brain atrophy. In the HC group, we observed physiological changes in PCC connectivity in ventral visual stream areas and with PCC/P during the visual task, reflecting the successful involvement of these regions in visual processing. In the MCI group, the PCC connectivity changes were disturbed and remained significant only with the anterior precuneus. In between-group comparison, we observed significant PPI effects in the right superior temporal gyrus in both MCI and AD as compared to HC. This change in connectivity may reflect ineffective "compensatory" mechanism present in the early pre-dementia stages of AD or abnormal modulation of brain connectivity due to the disease pathology. With the disease progression, these changes become more evident but less efficient in terms of compensation. This approach can separate the MCI from HC with 77% sensitivity and 89% specificity.

• Klíčová slova
• Dementia, Posterior cingulate, Precuneus, Psychophysiological interactions, Visual pathways, fMRI,
• MeSH
• Alzheimerova nemoc komplikace   MeSH
• kognitivní dysfunkce diagnostické zobrazování   etiologie   patologie   MeSH
• kyslík krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• modely neurologické MeSH
• mozek patologie   MeSH
• nervové dráhy diagnostické zobrazování   patofyziologie   MeSH
• počítačové zpracování obrazu MeSH
• psychofyzika MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• stárnutí * MeSH
• světelná stimulace MeSH
• zraková percepce fyziologie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kyslík MeSH

While previous studies suggested that perfusion abnormalities in Parkinson's disease (PD) are driven by dementia, our study aimed to identify perfusion underpinning of cognitive alteration in non-demented PD patients. Cerebral blood flow was measured using arterial spin labelling (ASL) in 28 PD patients (age 65 years ± 9.9 SD) and 16 age-matched healthy controls (HC) (age 65 years ± 7.8 SD), who also underwent neurological and cognitive testing. The 3D pseudocontinuous ASL and T2-weighted scans from 22 PD patients and 16 HC were analysed in a voxel-wise manner using SPM8 software. Associations between the ASL values in volumes of interest (VOIs) and behavioural and cognitive measures were assessed by Spearman correlation analysis. Posterior cortical hypoperfusion was found in PD patients compared to HC in the left supramarginal gyrus/superior temporal gyrus (VOI1) and left posterior cingulate/precuneus (VOI2). Positive correlation was revealed between perfusion in the VOI2 and Addenbrooke's Cognitive Examination Revised (ACE-R) scores after filtering out the effect of age, levodopa equivalent dose (LED), and total intracranial volume (TIV) (R = 0.51, p = 0.04). Conversely, negative correlation between VOI1 and ACE-R was detected (R = -0.62, p = 0.01) after regressing out the effects of motor impairment, age, LED, and TIV. In non-demented subjects with PD, blood flow abnormalities in precuneus/posterior cingulate were linked to the level of motor impairment and global cognitive performance. Oppositely, perfusion abnormalities in supramarginal gyrus might serve as a compensatory mechanism for brain degeneration and decreased cognitive performance.

• Klíčová slova
• Arterial spin labelling, Cognitive performance, Parkinson’s disease, Perfusion,
• MeSH
• cerebrovaskulární poruchy diagnostické zobrazování   patofyziologie   MeSH
• lidé MeSH
• magnetická rezonanční tomografie * MeSH
• mozková kůra diagnostické zobrazování   patofyziologie   MeSH
• mozkový krevní oběh fyziologie   MeSH
• Parkinsonova nemoc diagnostické zobrazování   patofyziologie   psychologie   MeSH
• počítačové zpracování obrazu MeSH
• pohybová aktivita MeSH
• průřezové studie MeSH
• senioři MeSH
• spinové značení MeSH
• stupeň závažnosti nemoci MeSH
• zobrazování trojrozměrné MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• spinové značení MeSH