scholarly journals Subcortical connectivity in dementia with Lewy bodies and Alzheimer's disease

2013 ◽  
Vol 203 (3) ◽  
pp. 209-214 ◽  
Author(s):  
Eva R. Kenny ◽  
John T. O'Brien ◽  
Michael J. Firbank ◽  
Andrew M. Blamire
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Resting State ◽  
Dementia With Lewy Bodies ◽  
Lewy Bodies ◽  
Low Frequency ◽  
Blood Oxygen Level Dependent ◽  
Bold Signal ◽  
Blood Oxygen Level

BackgroundResting-state functional magnetic resonance imaging (fMRI) can be used to measure correlations in spontaneous low-frequency fluctuations in the blood oxygen level-dependent (BOLD) signal which represent functional connectivity between key brain areas.AimsTo investigate functional connectivity with regions hypothesised to be differentially affected in dementia with Lewy bodies (DLB) compared with Alzheimer's disease and controls.MethodFifteen participants with probable DLB, 16 with probable Alzheimer's disease and 16 controls were scanned in the resting-state using a 3T scanner. The BOLD signal time-series of fluctuations in seed regions were correlated with all other voxels to measure functional connectivity.ResultsParticipants with DLB and Alzheimer's disease showed greater caudate and thalamic connectivity compared with controls. Those with DLB showed greater putamen connectivity compared with those with Alzheimer's disease and the controls. No regions showed less connectivity in DLB or Alzheimer's disease v. controls, or in DLB v. Alzheimer's disease.ConclusionsAltered connectivity in DLB and Alzheimer's disease provides new insights into the neurobiology of these disorders and may aid in earlier diagnosis.

scholarly journals Changes in gray matter volume and functional connectivity in dementia with Lewy bodies compared to Alzheimer’s disease and normal aging: implications for fluctuations

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Eléna Chabran ◽  
Vincent Noblet ◽  
Paulo Loureiro de Sousa ◽  
Catherine Demuynck ◽  
Nathalie Philippi ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Gray Matter ◽  
Resting State ◽  
Dementia With Lewy Bodies ◽  
Gray Matter Volume ◽  
Lewy Bodies ◽  
Elderly Subjects ◽  
Matter Volume

Abstract Background Fluctuations are one of the core clinical features characterizing dementia with Lewy bodies (DLB). They represent a determining factor for its diagnosis and strongly impact the quality of life of patients and their caregivers. However, the neural correlates of this complex symptom remain poorly understood. This study aimed to investigate the structural and functional changes in DLB patients, compared to Alzheimer’s disease (AD) patients and healthy elderly subjects, and their potential links with fluctuations. Methods Structural and resting-state functional MRI data were collected from 92 DLB patients, 70 AD patients, and 22 control subjects, who also underwent a detailed clinical examination including the Mayo Clinic Fluctuation Scale. Gray matter volume changes were analyzed using whole-brain voxel-based morphometry, and resting-state functional connectivity was investigated using a seed-based analysis, with regions of interest corresponding to the main nodes of the salience network (SN), frontoparietal network (FPN), dorsal attention network (DAN), and default mode network (DMN). Results At the structural level, fluctuation scores in DLB patients did not relate to the atrophy of insular, temporal, and frontal regions typically found in this pathology, but instead showed a weak correlation with more subtle volume reductions in different regions of the cholinergic system. At the functional level, the DLB group was characterized by a decreased connectivity within the SN and attentional networks, while the AD group showed decreases within the SN and DMN. In addition, higher fluctuation scores in DLB patients were correlated to a greater connectivity of the SN with the DAN and left thalamus, along with a decreased connectivity between the SN and DMN, and between the right thalamus and both the FPN and DMN. Conclusions Functional connectivity changes, rather than significant gray matter loss, could play an important role in the emergence of fluctuations in DLB. Notably, fluctuations in DLB patients appeared to be related to a disturbed external functional connectivity of the SN, which may lead to less relevant transitions between different cognitive states in response to internal and environmental stimuli. Our results also suggest that the thalamus could be a key region for the occurrence of this symptom.

scholarly journals Differential effects of anesthetics on resting state functional connectivity in the mouse

2019 ◽  
Vol 40 (4) ◽  
pp. 875-884 ◽  
Author(s):  
Hongyu Xie ◽  
David Y Chung ◽  
Sreekanth Kura ◽  
Kazutaka Sugimoto ◽  
Sanem A Aykan ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Chloral Hydrate ◽  
Low Frequency ◽  
Blood Oxygen Level Dependent ◽  
Resting State Functional Connectivity ◽  
Blood Oxygen Level ◽  
Intrinsic Signal ◽  
Optical Intrinsic Signal ◽  
Important Approach

Blood oxygen level-dependent (BOLD) functional MRI (fMRI) is a standard approach to examine resting state functional connectivity (RSFC), but fMRI in animal models is challenging. Recently, functional optical intrinsic signal imaging—which relies on the same hemodynamic signal underlying BOLD fMRI—has been developed as a complementary approach to assess RSFC in mice. Since it is difficult to ensure that an animal is in a truly resting state while awake, RSFC measurements under anesthesia remain an important approach. Therefore, we systematically examined measures of RSFC using non-invasive, widefield optical intrinsic signal imaging under five different anesthetics in male C57BL/6J mice. We find excellent seed-based, global, and interhemispheric connectivity using tribromoethanol (Avertin) and ketamine–xylazine, comparable to results in the literature including awake animals. Urethane anesthesia yielded intermediate results, while chloral hydrate and isoflurane were both associated with poor RSFC. Furthermore, we found a correspondence between the strength of RSFC and the power of low-frequency hemodynamic fluctuations. In conclusion, Avertin and ketamine–xylazine provide robust and reproducible measures of RSFC in mice, whereas chloral hydrate and isoflurane do not.

scholarly journals Dynamic functional connectivity changes in dementia with Lewy bodies and Alzheimer's disease

2019 ◽  
Vol 22 ◽  
pp. 101812 ◽  
Author(s):  
Julia Schumacher ◽  
Luis R. Peraza ◽  
Michael Firbank ◽  
Alan J. Thomas ◽  
Marcus Kaiser ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Dementia With Lewy Bodies ◽  
Lewy Bodies ◽  
Dynamic Functional Connectivity

scholarly journals The variability of functional MRI brain signal increases in Alzheimer's disease at cardiorespiratory frequencies

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Timo Tuovinen ◽  
Janne Kananen ◽  
Zalan Rajna ◽  
Johannes Lieslehto ◽  
Vesa Korhonen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Blood Oxygen Level Dependent ◽  
Present Observation ◽  
Blood Oxygen ◽  
Bold Signal ◽  
Blood Oxygen Level ◽  
Brain Hemodynamics ◽  
Fluid Convection ◽  
Signal Variability

AbstractBiomarkers sensitive to prodromal or early pathophysiological changes in Alzheimer’s disease (AD) symptoms could improve disease detection and enable timely interventions. Changes in brain hemodynamics may be associated with the main clinical AD symptoms. To test this possibility, we measured the variability of blood oxygen level-dependent (BOLD) signal in individuals from three independent datasets (totaling 80 AD patients and 90 controls). We detected a replicable increase in brain BOLD signal variability in the AD populations, which constituted a robust biomarker for clearly differentiating AD cases from controls. Fast BOLD scans showed that the elevated BOLD signal variability in AD arises mainly from cardiovascular brain pulsations. Manifesting in abnormal cerebral perfusion and cerebrospinal fluid convection, present observation presents a mechanism explaining earlier observations of impaired glymphatic clearance associated with AD in humans.

scholarly journals Dynamic functional connectivity changes in dementia with Lewy bodies and Alzheimer’s disease

2018 ◽  
Author(s):  
Julia Schumacher ◽  
Luis R. Peraza ◽  
Michael Firbank ◽  
Alan J. Thomas ◽  
Marcus Kaiser ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Functional Connectivity ◽  
Resting State ◽  
Dementia With Lewy Bodies ◽  
Lewy Bodies ◽  
Brain Network ◽  
Visual Hallucinations ◽  
Dynamic Functional Connectivity ◽  
Dynamic Connectivity ◽  
Cognitive Fluctuations

AbstractWe studied the dynamic functional connectivity profile of dementia with Lewy bodies (DLB) and Alzheimer’s disease (AD) and the relationship between dynamic connectivity and the temporally transient symptoms of cognitive fluctuations and visual hallucinations in DLB.Resting state fMRI data from 31 DLB, 29 AD, and 31 healthy control participants were analysed using dual regression to determine between-network functional connectivity. We used a sliding window approach followed by k-means clustering and dynamic network analyses to study dynamic functional connectivity changes associated with AD and DLB. Network measures that showed significant group differences were tested for correlations with clinical symptom severity.AD and DLB patients spent more time than controls in sparse connectivity configurations with absence of strong positive and negative connections and a relative isolation of motor networks from other networks. Additionally, DLB patients spent less time in a more strongly connected state and the variability of global brain network efficiency was reduced in DLB compared to controls. However, there were no significant correlations between dynamic connectivity measures and clinical scores.The loss of global efficiency variability in DLB might indicate the presence of an abnormally rigid brain network and the lack of economical dynamics, factors which could contribute to an inability to respond appropriately to situational demands. However, the absence of significant clinical correlations indicates that the severity of transient cognitive symptoms such as cognitive fluctuations and visual hallucinations might not be directly related to these dynamic connectivity changes observed during a short resting state scan.

scholarly journals Dynamic Functional Connectivity Changes in Dementia with Lewy Bodies and Alzheimer's Disease

2018 ◽  
Author(s):  
Julia Schumacher ◽  
Luis R. Peraza ◽  
Michael Firbank ◽  
Alan J. Thomas ◽  
Marcus Kaiser ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Dementia With Lewy Bodies ◽  
Lewy Bodies ◽  
Dynamic Functional Connectivity

scholarly journals Functional connectivity in cortical regions in dementia with Lewy bodies and Alzheimer's disease

Brain ◽  
2011 ◽  
Vol 135 (2) ◽  
pp. 569-581 ◽  
Author(s):  
Eva R. Kenny ◽  
Andrew M. Blamire ◽  
Michael J. Firbank ◽  
John T. O'Brien
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Dementia With Lewy Bodies ◽  
Lewy Bodies ◽  
Cortical Regions

Generalized Rhythmic Delta Activity Frontally Predominant Differentiates Dementia With Lewy Bodies From Alzheimer's Disease and Parkinson's Disease Dementia: A Conventional Electroencephalography Visual Analysis

2021 ◽  
pp. 155005942199714
Author(s):  
Lucia Zinno ◽  
Anna Negrotti ◽  
Chiara Falzoi ◽  
Giovanni Messa ◽  
Matteo Goldoni ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Parkinson’S Disease ◽  
Alzheimer's Disease ◽  
Parkinson's Disease ◽  
Cognitive Impairment ◽  
Dementia With Lewy Bodies ◽  
Visual Analysis ◽  
Lewy Bodies ◽  
Delta Activity ◽  
Rhythmic Delta Activity

Introduction. An easily accessible and inexpensive neurophysiological technique such as conventional electroencephalography may provide an accurate and generally applicable biomarker capable of differentiating dementia with Lewy bodies (DLB) from Alzheimer’s disease (AD) and Parkinson’s disease-associated dementia (PDD). Method. We carried out a retrospective visual analysis of resting-state electroencephalography (EEG) recording of 22 patients with a clinical diagnosis of 19 probable and 3 possible DLB, 22 patients with probable AD and 21 with PDD, matched for age, duration, and severity of cognitive impairment. Results. By using the grand total EEG scoring method, the total score and generalized rhythmic delta activity frontally predominant (GRDAfp) alone or, even better, coupled with a slowing of frequency of background activity (FBA) and its reduced reactivity differentiated DLB from AD at an individual level with an high accuracy similar to that obtained with quantitative EEG (qEEG). GRDAfp alone could also differentiate DLB from PDD with a similar level of diagnostic accuracy. AD differed from PDD only for a slowing of FBA. The duration and severity of cognitive impairment did not differ between DLB patients with and without GRDAfp, indicating that this abnormal EEG pattern should not be regarded as a disease progression marker. Conclusions. The findings of this investigation revalorize the role of conventional EEG in the diagnostic workup of degenerative dementias suggesting the potential inclusion of GRDAfp alone or better coupled with the slowing of FBA and its reduced reactivity, in the list of supportive diagnostic biomarkers of DLB.

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