scholarly journals Decoupling of inter-regional functional connectivity and regional neural activity in Alzheimer Disease

2019 ◽  
Author(s):  
Somayeh Maleki-Balajoo ◽  
Farzaneh Rahmani ◽  
Reza Khosrowabadi ◽  
Chun Meng ◽  
Timo Grimmer ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Neural Activity ◽  
Healthy Subjects ◽  
Disease Status ◽  
Clustering Coefficient ◽  
Healthy Individuals ◽  
Moderated Multiple Regression ◽  
Topological Measures ◽  
Regional Metabolism ◽  
Local Segregation

AbstractAlzheimer’s disease (AD) and mild cognitive impairment (MCI) are characterized by aberrant regional neural activity and disrupted inter-regional functional connectivity (FC). It is, however, poorly understood how changes in regional neural activity and inter-regional FC interact in AD and MCI. Here, we investigated the link between regional neural activity and nodal topological measures of FC through simultaneous PET/MR measurement in 20 patients with MCI, 33 patients with AD, and 26 healthy individuals. First, we assessed regional glucose metabolism identified through FDG-PET (rFDG) (as a proxy of regional neural activity), and regional FC topology through clustering coefficient (CC) and degree centrality (DC) (as surrogates of local segregation and global connectivity, respectively). Next, we examined the potential moderating effect of disease status (AD or MCI) on the link between rFDG and FC topology using hierarchical moderated multiple regression analysis. Alterations in rFDG, CC, and DC were widespread in patients, and AD alters physiological coupling between regional metabolism and functional connectivity particularly in the inferior temporal gyus and supplementary motor areas. While rFDG correlated with CC in healthy subjects, this correlation was lost in AD patients. We suggest that AD pathology decouples the normal association between regional neural activity and functional segregation.

scholarly journals Decoupling of regional neural activity and inter-regional functional connectivity in Alzheimer’s Disease – a simultaneous PET/MRI study

2021 ◽  
Author(s):  
Somayeh Maleki Balajoo ◽  
Farzaneh Rahmani ◽  
Reza Khosrowabadi ◽  
Chun Meng ◽  
Simon B. Eickhoff ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Glucose Metabolism ◽  
Neural Activity ◽  
Fdg Pet ◽  
Disease Status ◽  
Blood Oxygenation ◽  
Clustering Coefficient ◽  
Regional Metabolism

Abstract Purpose: Alzheimer’s disease (AD) and mild cognitive impairment (MCI), a syndrome at-risk for AD, are characterized by both aberrant regional neural activity and disrupted inter-regional functional connectivity (FC). It is, however, not clear how aberrant regional neural activity and inter-regional FC interact across MCI and AD. Thus, we investigated the interplay between regional neural activity and inter-regional topological measures of FC in MCI and AD using simultaneous PET/MR measurement.Methods: We scanned 19 patients with MCI, 33 patients with AD, and 26 healthy individuals by simultaneous FDG-PET/resting-state fMRI. First, we assessed regional glucose metabolism identified through FDG-PET (as a proxy of regional neural activity), and inter-regional FC topology through clustering coefficient and degree centrality (as surrogates of local segregation and global connectivity, respectively, based on fMRI blood oxygenation). Next, we examined the potential moderating effect of disease status (MCI or AD) on the link between regional metabolism and inter-regional FC topology using hierarchical moderated multiple regression analysis.Results: Not only regional metabolism and inter-regional FC metrics were disrupted in in MCI and AD patients, but also AD significantly alters coupling between regional metabolism and inter-regional FC, particularly in the right inferior temporal, supplementary motor area and planum temporal areas, where AD moderated the effect of their regional glucose metabolism on predicting their inter-reginal FC. Conclusion: Our findings demonstrated that AD decouples the association between regional neural activity and functional segregation.

Altered cerebrocerebellar functional connectivity in patients with obstructive sleep apnea and its association with cognitive function

SLEEP ◽  
2021 ◽  
Author(s):  
Hea Ree Park ◽  
Jungho Cha ◽  
Eun Yeon Joo ◽  
Hosung Kim
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Functional Connectivity ◽  
Functional Mri ◽  
Default Mode Network ◽  
Healthy Subjects ◽  
Clustering Coefficient ◽  
Significant Group ◽  
Default Mode ◽  
Obstructive Sleep

Abstract Study Objectives Previous functional MRI studies have reported altered brain networks in patients with obstructive sleep apnea (OSA). However, the extent and pattern of abnormal connectivity were inconsistent across studies, and cerebrocerebellar connections have been rarely assessed. We investigated functional network changes in cerebral and cerebellar cortices of OSA patients. Methods Resting-state functional MRI, polysomnography and neuropsychological (NP) test data were acquired from 74 OSA patients (age: 45.8±10.7 years) and 33 healthy subjects (39.6±9.3 years). Connectivity matrices were extracted by computing correlation coefficients from various ROIs, and Fisher r-to-z transformations. In the functional connections that showed significant group differences, linear regression was conducted to examine the association between connectivity and clinical characteristics. Results Patients with OSA showed reduced functional connectivity (FC) in cerebrocerebellar connections linking different functional networks, and greater FC in cortical between-network connections in prefrontal regions involving the default mode network and the control network. For OSA group, we found no correlation between FC and sleep parameters including lowest SaO2 and arousal index in the connections where significant associations were observed in healthy subjects. FC changes in default mode network (DMN) areas were related to reduced verbal fluency in OSA. Lower local efficiency and lower clustering coefficient of the salience network in the left cerebellum were also observed in OSA. Conclusions OSA affects mainly the cerebrocerebellar pathway. The disruption of function in these connections are related to sleep fragmentation and hypoxia during sleep. These abnormal network functions, especially DMN, are suggested to participate in cognitive decline of OSA.

P0730ALTERATION OF BRAIN CONNECTIVITY IN NEUROLOGICALLY ASYMPTOMATIC PATIENTS WITH CHRONIC KIDNEY DISEASE

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Yang Wook Kim ◽  
YOO JIN Lee ◽  
Bong Soo Park ◽  
Sihyung Park ◽  
Chang min Heo ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Functional Connectivity ◽  
Kidney Disease ◽  
Betweenness Centrality ◽  
Healthy Subjects ◽  
Brain Connectivity ◽  
Structural Connectivity ◽  
Clustering Coefficient ◽  
Healthy Controls ◽  
Asymptomatic Patients

Abstract Background and Aims Our previous study demonstrated that patients in End stage renal disease had decreased structural and functional brain connectivity, and there was significant association between brain connectivity and cognitive function. The aim of this study was to evaluate the alterations of structural and functional connectivity using graph theoretical analysis in the neurologically asymptomatic patients with relatively early stage chronic kidney disease (CKD). Method We prospectively enrolled neurologically asymptomatic 20 patients with CKD stage 3 and 20 healthy controls, and all of the subjects underwent diffusion tensor imaging (DTI) and resting state functional MRI (rs-fMRI). Using data from the structural and functional connectivity matrix based on DTI and rs-fMRI, we calculated network measures, including global efficiency, local efficiency, mean clustering coefficient, characteristic path length, and small-worldness index, and investigated the differences between the patients with CKD and healthy controls. Results The patients with CKD had altered global structural connectivity and preserved functional connectivity compared to healthy controls. The all of the measures of global structural connectivity were significantly different between the patients with CKD and healthy controls. However, all of the measures of global functional connectivity in the CKD patients were not different from those in healthy participants. In the CKD patients, the functional betweenness centrality of the right insular cortex, right occipital pole, and right thalamus was significantly different from that in healthy subjects. The structural betweenness centrality of the left calcarine, right posterior cingulum was significantly different from that in healthy subjects. Conclusion There were significant alterations of global structural connectivity between patients with CKD and control. However, functional connectivity of brain network was preserved in contrast to ESRD patients.

A Comparative Evaluation of Serum and Salivary Total Proteins and Immunoglobulins in Patients with Hepatitis A and Healthy Subjects

2018 ◽  
Vol 69 (5) ◽  
pp. 1125-1128
Author(s):  
Daniela G. Balan ◽  
Dan Piperea Sianu ◽  
Iulia I. Stanescu ◽  
Dorin Ionescu ◽  
Andra Elena Stroescu Balcangiu ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Comparative Evaluation ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Point Of View ◽  
Healthy Individuals ◽  
Total Proteins ◽  
Statistical Point ◽  
Immunological Tests ◽  
Acute Hepatitis A

Assessment of changes in total proteins level, serum and saliva IgG and IgA levels, serum IgM level, serum and saliva IgA/IgG ratio. The study was conducted on a group of 40 subjects, divided into 2 lots: the first lot consisting of 20 healthy individuals and the second consisting of 20 patients with hepatitis with hepatitis A virus (HAV). The levels of total proteins, serum and saliva IgG and IgA, serum IgM and serum and saliva IgA/IgG ratio have higher values in patients with hepatitis A, in comparison to healthy subjects, without necessarily exceeding the maximum admitted value. The results are significant from a statistical point of view. Due to the sensitivity and specificity of salivary anti-HAV IgM and IgG in patients with acute hepatitis A, compared with healthy subjects, there is a possibility of using salivary immunological tests instead of serum tests for the diagnosis and epidemiological study of HAV infection.

Comparison of the Aditus ad Antrum Diameter on CT between Patients with Chronic Otitis Media and Healthy Individuals

2019 ◽  
Vol 15 (10) ◽  
pp. 990-993 ◽  
Author(s):  
Elif Gündoğdu ◽  
Uğur Toprak
Keyword(s):  
Computed Tomography ◽  
Otitis Media ◽  
Middle Ear ◽  
Healthy Subjects ◽  
Normal Values ◽  
Chronic Otitis Media ◽  
Healthy Individuals ◽  
Inner Diameter ◽  
Male Patients ◽  
The Right

Background: The middle ear cavity is ventilated through the aditus ad antrum. Aditus blockage contributes to the pathology of otitis media. Objective: To determine the normal values of the aditus ad antrum diameter on computed tomography and to investigate its relationship with chronic otitis media and related pathologies (tympanosclerosis and myringosclerosis). Methods: The temporal CT images of 162 individuals were evaluated retrospectively. In the axial sections, the inner diameter of the aditus was measured at the narrowest point at the cortex. The differences in diameter were compared between diseased and healthy ears. Results: In healthy individuals, the diameter was narrower in women. There was no difference between the right and left ears in healthy subjects. No correlation was found between age and diameter. In male patients with myringosclerosis, the diameter was slightly narrower on both sides but more marked on the left. In female patients with myringosclerosis, the diameter in both ears was slightly narrower. In cases of otitis media and tympanosclerosis, the diameter was less than that of healthy individuals, despite the lack of statistically significant result in all cases. Conclusion: The aditus ad antrum was narrower in diseased ears, indicating that a blocked aditus may contribute to the development of otitis media, as well as mucosal diseases.

Prevalence of Toxoplasma gondii and Toxocara canis among Myositis Patients in Southwest of Iran

2019 ◽  
Vol 20 ◽  
Author(s):  
Jasem Saki ◽  
Karim Mowla ◽  
Reza Arjmand ◽  
Forough Kazemi ◽  
Somayeh Fallahizadeh
Keyword(s):  
Toxoplasma Gondii ◽  
Nested Pcr ◽  
Healthy Subjects ◽  
Toxocara Canis ◽  
Control Group ◽  
Igg Antibodies ◽  
Healthy Individuals ◽  
High Prevalence ◽  
Acute Toxoplasmosis ◽  
Southwest Of Iran

Introduction: Parasitic myositis is caused by some parasites such as T. gondii and T. canis. So, the aim of the study was to evaluate the prevalence T. gondii and T. canis in patients with myositis and healthy individuals. Methods: A total of 108 samples were randomly selected as the control (54 healthy individuals) and test (54 myositis patients) groups. IgG and IgM antibodies against T. gondii and IgG antibodies against T. canis were measured by the ELISA. The detection of chronic and acute toxoplasmosis was performed by the ELISA IgG avidity. The presence of T. gondii in blood was evaluated by the nested-PCR. Results: Of 108, 33 (30.6%) cases were detected positive for IgG against T. gondii that 19 (35.2%) and 14 (25.9%) were observed in myositis patients and healthy individuals, respectively (P=0.296). Of 19 positive cases, 12 (63.2%) and 7 (36.8%) cases were detected as chronic and acute toxoplasmosis, respectively, while, all positive cases in the control group had chronic toxoplasmosis (P=0.013). One (1.9%) sample was detected positive for anti- Toxoplasma gondii IgM and two (3.7%) samples were found positive for IgG against T. canis by the ELISA that these positive cases were observed only in myositis patients (P=1.000 P=0.495, respectively). B1 T. gondii gene was amplified in 12 (63.2%) and 1 (7.1%) in myositis patients and healthy subjects (P=0.001). Conclusions: Our findings showed that there was a relatively high prevalence of acute toxoplasmosis in myositis patients in comparison with the control subjects in southwest of Iran.

Methylphenidate reduces orienting bias in healthy individuals

2021 ◽  
pp. 026988112199688
Author(s):  
Leehe Peled-Avron ◽  
Hagar Gelbard Goren ◽  
Noa Brande-Eilat ◽  
Shirel Dorman-Ilan ◽  
Aviv Segev ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Asymmetric Effect ◽  
Healthy Individuals ◽  
Double Blind ◽  
Spatial Orienting ◽  
Individual Trait ◽  
Neurological Patients ◽  
Dopamine Signaling ◽  
First Time ◽  
Neural Effect

Background: Healthy individuals show subtle orienting bias, a phenomenon known as pseudoneglect, reflected in a tendency to direct greater attention toward one hemispace. Accumulating evidence indicates that this bias is an individual trait, and attention is preferentially directed contralaterally to the hemisphere with higher dopamine signaling. Administration of methylphenidate (MPH), a dopamine transporter inhibitor, was shown to normalize aberrant spatial attention bias in psychiatric and neurological patients, suggesting that the reduced orienting bias following administration of MPH reflects an asymmetric effect of the drug, increasing extracellular dopamine in the hemisphere with lower dopamine signaling. Aim: We predicted that, similarly to its effect on patients with brain pathology, MPH will reduce the orienting bias in healthy subjects. Methods: To test this hypothesis, we examined the behavioral effects of a single dose (20 mg) of MPH on orienting bias in 36 healthy subjects (18 females) in a randomized, double-blind placebo-controlled, within-subject design, using the greyscales task, which has been shown to detect subtle attentional biases in both patients and healthy individuals. Results/outcomes: Results demonstrate that healthy individuals vary in both direction and magnitude of spatial orienting bias and show reduced magnitude of orienting bias following MPH administration, regardless of the initial direction of asymmetry. Conclusions/interpretations: Our findings reveal, for the first time in healthy subjects, that MPH decreases spatial orienting bias in an asymmetric manner. Given the well-documented association between orienting bias and asymmetric dopamine signaling, these findings also suggest that MPH might exert a possible asymmetric neural effect in the healthy brain.

scholarly journals Functional Brain Network Topology Discriminates between Patients with Minimally Conscious State and Unresponsive Wakefulness Syndrome

2019 ◽  
Vol 8 (3) ◽  
pp. 306 ◽  
Author(s):  
Alberto Cacciola ◽  
Antonino Naro ◽  
Demetrio Milardi ◽  
Alessia Bramanti ◽  
Leonardo Malatacca ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Network Topology ◽  
Minimally Conscious State ◽  
Conscious State ◽  
Clustering Coefficient ◽  
Unresponsive Wakefulness Syndrome ◽  
Topological Network ◽  
Functional Brain Network ◽  
Minimally Conscious ◽  
Nodal Level

Consciousness arises from the functional interaction of multiple brain structures and their ability to integrate different complex patterns of internal communication. Although several studies demonstrated that the fronto-parietal and functional default mode networks play a key role in conscious processes, it is still not clear which topological network measures (that quantifies different features of whole-brain functional network organization) are altered in patients with disorders of consciousness. Herein, we investigate the functional connectivity of unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS) patients from a topological network perspective, by using resting-state EEG recording. Network-based statistical analysis reveals a subnetwork of decreased functional connectivity in UWS compared to in the MCS patients, mainly involving the interhemispheric fronto-parietal connectivity patterns. Network topological analysis reveals increased values of local-community-paradigm correlation, as well as higher clustering coefficient and local efficiency in UWS patients compared to in MCS patients. At the nodal level, the UWS patients showed altered functional topology in several limbic and temporo-parieto-occipital regions. Taken together, our results highlight (i) the involvement of the interhemispheric fronto-parietal functional connectivity in the pathophysiology of consciousness disorders and (ii) an aberrant connectome organization both at the network topology level and at the nodal level in UWS patients compared to in the MCS patients.

CDH1 germline mutations in healthy individuals from families with the hereditary diffuse gastric cancer syndrome

2021 ◽  
pp. jmedgenet-2021-108226
Author(s):  
Giovanni Corso ◽  
Francesca Magnoni ◽  
Giulia Massari ◽  
Cristina Maria Trovato ◽  
Alessandra Margherita De Scalzi ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Healthy Subjects ◽  
Relevant Literature ◽  
Germline Mutations ◽  
Hereditary Diffuse Gastric Cancer ◽  
Diffuse Gastric Cancer ◽  
Missense Mutations ◽  
Healthy Individuals ◽  
Cancer Syndrome ◽  
The Difference

The objective of this study was to determining the frequency of different sub-types of pathogenic CDH1 germline mutations in healthy and asymptomatic individuals from families with the hereditary diffuse gastric cancer (HDGC) syndrome. Relevant literature dating from 1998 to 2019 was systematically searched for data on CDH1 germline mutations. The collected variants were classified according to their subtype into the following classes: missense, non-sense, splicing, insertions and deletions. The χ2 test was used to estimate if the difference observed between patients with gastric cancer (GC) and unaffected individuals was statistically significant. CDH1 genetic screening data were retrieved for 224 patients with GC and 289 healthy individuals. Among the subjects that had tested CDH1 positive, splicing mutations were found in 30.4% of the healthy individuals and in 15.2% of the patients with GC (p=0.0076). Missense mutations were also found to occur in healthy subjects with higher frequency (22.2%) than in GC-affected individuals (18.3%), but the difference was not significant in this case. In families meeting the clinical criteria for the HDGC syndrome, CDH1 splicing and missense germline mutations have been reported to occur with higher frequency in healthy subjects than in patients with cancer. This preliminary observation suggests that not all pathogenic CDH1 germline mutations confer the same risk of developing GC.

scholarly journals Functional Brain Connectivity during Multiple Motor Imagery Tasks in Spinal Cord Injury

2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Alkinoos Athanasiou ◽  
Nikos Terzopoulos ◽  
Niki Pandria ◽  
Ioannis Xygonakis ◽  
Nicolas Foroglou ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Functional Connectivity ◽  
Motor Imagery ◽  
Healthy Subjects ◽  
Brain Connectivity ◽  
Descending Pathways ◽  
Brain Organization ◽  
Sensorimotor Network ◽  
Cord Injury

Reciprocal communication of the central and peripheral nervous systems is compromised during spinal cord injury due to neurotrauma of ascending and descending pathways. Changes in brain organization after spinal cord injury have been associated with differences in prognosis. Changes in functional connectivity may also serve as injury biomarkers. Most studies on functional connectivity have focused on chronic complete injury or resting-state condition. In our study, ten right-handed patients with incomplete spinal cord injury and ten age- and gender-matched healthy controls performed multiple visual motor imagery tasks of upper extremities and walking under high-resolution electroencephalography recording. Directed transfer function was used to study connectivity at the cortical source space between sensorimotor nodes. Chronic disruption of reciprocal communication in incomplete injury could result in permanent significant decrease of connectivity in a subset of the sensorimotor network, regardless of positive or negative neurological outcome. Cingulate motor areas consistently contributed the larger outflow (right) and received the higher inflow (left) among all nodes, across all motor imagery categories, in both groups. Injured subjects had higher outflow from left cingulate than healthy subjects and higher inflow in right cingulate than healthy subjects. Alpha networks were less dense, showing less integration and more segregation than beta networks. Spinal cord injury patients showed signs of increased local processing as adaptive mechanism. This trial is registered with NCT02443558.

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