scholarly journals The brain structural and functional anomaly associated with simultanagnosia in patients with posterior cortical atrophy

2020 ◽  
Author(s):  
Yang Liu ◽  
Caishui Yang ◽  
Chunlei Cui ◽  
Yue Cui ◽  
Donglai Jing ◽  
...  
Keyword(s):  
Functional Mri ◽  
Grey Matter ◽  
Cortical Atrophy ◽  
Functional Coupling ◽  
Posterior Cortical Atrophy ◽  
Significant Difference ◽  
Computer Based ◽  
Middle Occipital Gyrus ◽  
The Brain ◽  
Left Middle

Abstract Backgroud Posterior cortical atrophy (PCA) is a rare neurodegenerative disease characterized by impairments in visual processing and in other relatively selective posterior cortical functions, mainly involving occipito-parietal regions. As the most common and important clinical manifestation, simultanagnosia is a profound inability of a patient with PCA to integrate multiple visual elements and to precept the global precedence within a scene. With few reports, the structural and functional changes in the brain associated with simultanagnosia are still yet comprehended more fully.Methods This study recruited 18 PCA patients with simultanagnosia, 29 patients with Alzheimer’s disease (AD) and 20 cognitively normal controls (NC). All subjects underwent a full neuropsychological evaluation, picture-/computer-based simultanagnosia tests, structural and resting-state functional MRI. Grey matter volume (GMV) was assessed by voxel-based morphometry, while seed based intrinsic functional connectivity (iFC) was evaluated based on the PCA-specific grey matter injuries in contrast to AD. Finally, the correlations between the statistically significant structural or functional MRI features and the simultanagnosia were evaluated in PCA patients.Results We found that, between PCA and AD patients, there was no significant difference in clinical dementia rating, immediate memory and delayed memory, while the marked difference was exhibited in neuropsychological assessments, and also in the picture-based and computer-based test score (P<0.01). In addition to brain areas where both PCA and AD patients had compatible regional GMV reduction each in contrast with NC group, the left middle occipital gyrus and ventral occipital areas were specifically affected by PCA relative to AD. Also in contrast to AD, PCA had lower iFC from left middle occipital gyrus, left lingua gyrus and right middle occipital gyrus. Moreover, we found that GMV of left middle occipital gyrus, its functional coupling to right superior occipital gyrus, the GMV of left inferior occipital gyrus and the iFC from right middle occipital gyrus to left superior parietal gyrus were each correlated to simultanagnosia (r=0.670, p=0.002; r=-0.517, p<0.001; r=0.605 p=0.008; r=0.778, p<0.001, respectively) in PCA patients.Conclusions Simultanagnosia is associated with the lower structural GMV and lower iFC in the left middle occipital gyrus and the left inferior occipital gyrus in PCA.

scholarly journals Brain structural and functional anomalies associated with simultanagnosia in patients with posterior cortical atrophy

2021 ◽  
Author(s):  
Yue Cui ◽  
Yang Liu ◽  
Caishui Yang ◽  
Chunlei Cui ◽  
Donglai Jing ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Gray Matter ◽  
Gray Matter Volume ◽  
Cortical Atrophy ◽  
Posterior Cortical Atrophy ◽  
Matter Volume ◽  
Intrinsic Functional Connectivity ◽  
Middle Occipital Gyrus ◽  
The Right ◽  
Left Middle

AbstractSimultanagnosia is a common symptom of posterior cortical atrophy, and its association with brain structural and functional changes remains unclear. In our study, 18 posterior cortical atrophy patients with simultanagnosia, 29 patients with Alzheimer’s disease and 20 cognitively normal controls were recruited and subjected to full neuropsychological evaluation, including simultanagnosia tests, and structural and resting-state functional MRI. The gray matter volume was assessed by voxel-based morphometry, while the intrinsic functional connectivity was evaluated using the reduced gray matter volume regions of interest as the seed. In contrast to the patients with Alzheimer’s disease, those with posterior cortical atrophy showed the following: (1) markedly lower simultanagnosia test scores, (2) an altered regional gray matter volume of the left middle occipital gyrus and ventral occipital areas, and (3) lowered intrinsic functional connectivity with the left middle occipital gyrus, left lingual gyrus and right middle occipital gyrus separately. Additionally, the gray matter volume of the left middle occipital gyrus and left inferior occipital gyrus were each correlated with simultanagnosia in posterior cortical atrophy patients. The intrinsic functional connectivity of the left middle occipital gyrus with the right superior occipital gyrus and that of the right middle occipital gyrus with the left superior parietal gyrus were also correlated with simultanagnosia in posterior cortical atrophy patients. In summary, this study indicated that simultanagnosia is associated with gray matter reductions and decreased functional connectivity in the left middle occipital gyrus and the left inferior occipital gyrus in patients with posterior cortical atrophy.

scholarly journals Longitudinal neuroimaging biomarkers differ across Alzheimer’s disease phenotypes

Brain ◽  
2020 ◽  
Vol 143 (7) ◽  
pp. 2281-2294 ◽  
Author(s):  
Irene Sintini ◽  
Jonathan Graff-Radford ◽  
Matthew L Senjem ◽  
Christopher G Schwarz ◽  
Mary M Machulda ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Grey Matter ◽  
Clinical Phenotype ◽  
Principal Component ◽  
Cortical Atrophy ◽  
Posterior Cortical Atrophy ◽  
Longitudinal Patterns ◽  
Progressive Aphasia ◽  
Neuroimaging Biomarkers

Abstract Alzheimer’s disease can present clinically with either the typical amnestic phenotype or with atypical phenotypes, such as logopenic progressive aphasia and posterior cortical atrophy. We have recently described longitudinal patterns of flortaucipir PET uptake and grey matter atrophy in the atypical phenotypes, demonstrating a longitudinal regional disconnect between flortaucipir accumulation and brain atrophy. However, it is unclear how these longitudinal patterns differ from typical Alzheimer’s disease, to what degree flortaucipir and atrophy mirror clinical phenotype in Alzheimer’s disease, and whether optimal longitudinal neuroimaging biomarkers would also differ across phenotypes. We aimed to address these unknowns using a cohort of 57 participants diagnosed with Alzheimer’s disease (18 with typical amnestic Alzheimer’s disease, 17 with posterior cortical atrophy and 22 with logopenic progressive aphasia) that had undergone baseline and 1-year follow-up MRI and flortaucipir PET. Typical Alzheimer’s disease participants were selected to be over 65 years old at baseline scan, while no age criterion was used for atypical Alzheimer’s disease participants. Region and voxel-level rates of tau accumulation and atrophy were assessed relative to 49 cognitively unimpaired individuals and among phenotypes. Principal component analysis was implemented to describe variability in baseline tau uptake and rates of accumulation and baseline grey matter volumes and rates of atrophy across phenotypes. The capability of the principal components to discriminate between phenotypes was assessed with logistic regression. The topography of longitudinal tau accumulation and atrophy differed across phenotypes, with key regions of tau accumulation in the frontal and temporal lobes for all phenotypes and key regions of atrophy in the occipitotemporal regions for posterior cortical atrophy, left temporal lobe for logopenic progressive aphasia and medial and lateral temporal lobe for typical Alzheimer’s disease. Principal component analysis identified patterns of variation in baseline and longitudinal measures of tau uptake and volume that were significantly different across phenotypes. Baseline tau uptake mapped better onto clinical phenotype than longitudinal tau and MRI measures. Our study suggests that optimal longitudinal neuroimaging biomarkers for future clinical treatment trials in Alzheimer’s disease are different for MRI and tau-PET and may differ across phenotypes, particularly for MRI. Baseline tau tracer retention showed the highest fidelity to clinical phenotype, supporting the important causal role of tau as a driver of clinical dysfunction in Alzheimer’s disease.

scholarly journals Neural Basis of Depression Related to a Dominant Right Hemisphere: A Resting-State fMRI Study

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Mi Li ◽  
Hongpei Xu ◽  
Shengfu Lu
Keyword(s):  
Right Hemisphere ◽  
Inferior Frontal Gyrus ◽  
Middle Temporal Gyrus ◽  
Neural Basis ◽  
Middle Temporal ◽  
Middle Occipital Gyrus ◽  
The Right ◽  
Depressive Patients ◽  
The Brain ◽  
Left Middle

Background. In the past, studies on the lateralization of the left and right hemispheres of the brain suggested that depression is dominated by the right hemisphere of the brain, but the neural basis of this theory remains unclear. Method. Functional magnetic resonance imaging of the brain was performed in 22 depressive patients and 15 healthy controls. The differences in the mean values of the regional homogeneity (ReHo) of two groups were compared, and the low-frequency amplitudes of these differential brain regions were compared. Results. The results show that compared with healthy subjects, depressive patients had increased ReHo values in the right superior temporal gyrus, right middle temporal gyrus, left inferior temporal gyrus, left middle temporal gyrus, right middle frontal gyrus, triangular part of the right inferior frontal gyrus, orbital part of the right inferior frontal gyrus, right superior occipital gyrus, right middle occipital gyrus, bilateral anterior cingulate, and paracingulate gyri; reduced ReHo values were seen in the right fusiform gyrus, left middle occipital gyrus, left lingual gyrus, and left inferior parietal except in the supramarginal and angular gyri. Conclusions. The results show that regional homogeneity mainly occurs in the right brain, and the overall performance of the brain is such that right hemisphere synchronization is enhanced while left hemisphere synchronization is weakened. ReHo abnormalities in the resting state can predict abnormalities in individual neurological activities that reflect changes in the structure and function of the brain; abnormalities shown with this indicator are the neuronal basis for the phenomenon that the right hemisphere of the brain has a dominant effect on depression.

scholarly journals Case Report: [18F]PI2620 as a Tau Imaging Agent in Posterior Cortical Atrophy

2020 ◽  
Vol 11 ◽  
Author(s):  
Yu Kong ◽  
Kexin Xie ◽  
Hongwen Qiao ◽  
Yue Cui ◽  
Donglai Jing ◽  
...  
Keyword(s):  
Clinical Manifestations ◽  
Chinese Patient ◽  
Cortical Atrophy ◽  
Posterior Cortical Atrophy ◽  
Progressive Decline ◽  
Positron Emission ◽  
Magnetic Resonance Imaging Mri ◽  
Cortical Regions ◽  
Tau Aggregation ◽  
The Brain

Posterior cortical atrophy (PCA) is widely considered as an atypical variant of Alzheimer disease and is characterized by a progressive decline in visual function. PCA has been investigated from the standpoints of brain structure and metabolism, but tau deposition and its relationship to disease severity still remain unclear. Here, we used a novel tau ligand, [18F]PI2620, to visualize tau deposition in a PCA patient. The results showed that high [18F]PI2620 uptake in posterior cortical regions was associated with clinical manifestations, morphologic changes in the brain observed by magnetic resonance imaging (MRI), and hypometabolism detected by [18F] fluorodeoxyglucose (FDG) positron emission tomography (PET). This is the first report demonstrating a clinical anatomical correspondence between [18F]PI2620 PET results, clinical manifestations, MRI, and [18F]FDG PET findings in a Chinese patient with PCA. The results also support the utility of [18F]PI2620 for visualizing tau aggregation in PCA.

scholarly journals Effects of cortical damage on binocular depth perception

2016 ◽  
Vol 371 (1697) ◽  
pp. 20150254 ◽  
Author(s):  
Holly Bridge
Keyword(s):  
Depth Perception ◽  
Three Dimensional ◽  
Stereoscopic Vision ◽  
Temporal Lobectomy ◽  
Cortical Atrophy ◽  
Retinal Images ◽  
Posterior Cortical Atrophy ◽  
Retinal Input ◽  
The Brain ◽  
Binocular Depth

Stereoscopic depth perception requires considerable neural computation, including the initial correspondence of the two retinal images, comparison across the local regions of the visual field and integration with other cues to depth. The most common cause for loss of stereoscopic vision is amblyopia, in which one eye has failed to form an adequate input to the visual cortex, usually due to strabismus (deviating eye) or anisometropia. However, the significant cortical processing required to produce the percept of depth means that, even when the retinal input is intact from both eyes, brain damage or dysfunction can interfere with stereoscopic vision. In this review, I examine the evidence for impairment of binocular vision and depth perception that can result from insults to the brain, including both discrete damage, temporal lobectomy and more systemic diseases such as posterior cortical atrophy. This article is part of the themed issue ‘Vision in our three-dimensional world’.

The impact of localized grey matter damage on neighboring connectivity: posterior cortical atrophy and the visual network

2018 ◽  
Vol 13 (5) ◽  
pp. 1292-1301 ◽  
Author(s):  
Haya Glick-Shames ◽  
Yael Backner ◽  
Atira Bick ◽  
Noa Raz ◽  
Netta Levin
Keyword(s):  
Grey Matter ◽  
Cortical Atrophy ◽  
Posterior Cortical Atrophy ◽  
The Impact ◽  
Visual Network

scholarly journals Watching the Brain as It (Un)Binds: Beta Synchronization Relates to Distractor–Response Binding

2021 ◽  
pp. 1-14
Author(s):  
Bernhard Pastötter ◽  
Birte Moeller ◽  
Christian Frings
Keyword(s):  
Human Action ◽  
Brain Regions ◽  
Correlation Effect ◽  
Stimulus Onset ◽  
Event File ◽  
Stimulus Response ◽  
Event Files ◽  
Middle Occipital Gyrus ◽  
The Brain ◽  
Left Middle

Abstract Human action control relies on event files, that is, short-term stimulus–response bindings that result from the integration of perception and action. The present EEG study examined oscillatory brain activities related to the integration and disintegration of event files in the distractor–response binding (DRB) task, which relies on a sequential prime–probe structure with orthogonal variation of distractor and response relations between prime and probe. Behavioral results indicated a DRB effect in RTs, which was moderated by the duration of the RSI between prime response and probe stimulus onset. Indeed, a DRB effect was observed for a short RSI of 500 msec but not for a longer RSI of 2000 msec, indicating disintegration of event files over time. EEG results revealed a positive correlation between individual DRB in the RSI-2000 condition and postmovement beta synchronization after both prime and probe responses. Beamformer analysis localized this correlation effect to the middle occipital gyrus, which also showed highest coherency with precentral and inferior parietal brain regions. Together, these findings suggest that postmovement beta synchronization is a marker of event file disintegration, with the left middle occipital gyrus being a hub region for stimulus–response bindings in the visual DRB task.

scholarly journals Using fMRI to deepen our understanding of design fixation

2019 ◽  
Vol 5 ◽  
Author(s):  
Katherine K. Fu ◽  
Brian Sylcott ◽  
Kaustav Das
Keyword(s):  
Conceptual Design ◽  
Brain Activity ◽  
Design Problems ◽  
Design Fixation ◽  
Visuospatial Processing ◽  
Middle Occipital Gyrus ◽  
The Right ◽  
Mental Resources ◽  
The Brain ◽  
Left Middle

Design fixation refers to blind adherence to a set of ideas, which can limit the output of conceptual design. Engineering designers tend to fixate on features of pre-existing solutions and consequently generate designs with similar features. The objective of this study is to leverage functional magnetic resonance imaging (fMRI) to study the brain activity of engineering designers during conceptual design in order to understand whether/where design fixation can be detected in a person’s brain when solving design problems. Design solutions indicated that fixation effects were detectable at a statistically significant level. fMRI results show increased activation in areas associated with visuospatial processing when comparing ideation activities using an Example solution to No Example solution. Activation was found in the right inferior temporal gyrus, left middle occipital gyrus, and right superior parietal lobule regions. The left lingual and superior frontal gyri were found to be less active in the example condition; these gyri are close in proximity to the prefrontal cortex, associated with creative output. The spatial patterns of activation provide evidence that a shift in mental resources can occur when a designer becomes fixated. For designers, the timing of ideation relative to the timing of benchmarking existing solutions should be considered.

P2-434: Longitudinal changes in grey matter volumes and cortical thickness in Posterior Cortical Atrophy

2010 ◽  
Vol 6 ◽  
pp. S446-S447
Author(s):  
Manja Lehmann ◽  
Josephine Barnes ◽  
Gerard R. Ridgway ◽  
Elizabeth K. Warrington ◽  
Nick C. Fox ◽  
...  
Keyword(s):  
Cortical Thickness ◽  
Grey Matter ◽  
Cortical Atrophy ◽  
Posterior Cortical Atrophy ◽  
Longitudinal Changes

scholarly journals ACCUMBENS AREA MAY PLAY A ROLE IN FACIAL RECOGNITION OF EMOTIONS IN A LOW-EDUCATED POPULATION WITH MILD ALZHEIMER’S DISEASE

2021 ◽  
Author(s):  
Bruna Ciarlini ◽  
Flávia E Silva ◽  
Álissa Moura ◽  
Emmanuelle Sobreira ◽  
Roberto Paiva ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Facial Recognition ◽  
Cortical Atrophy ◽  
Voxel Based Morphometry ◽  
Significant Difference ◽  
Recognition Of Emotions ◽  
Low Educated ◽  
Adult Volunteers ◽  
The Brain

Background: There is no consensus on how recognition of universal facial emotions can be affected in low-educated individuals with Alzheimer’s Disease (AD). Objective: To assess the performance of Facial Recognition of Emotions Test (FERT) and to correlate with patterns of cortical atrophy measured through Voxel-Based Morphometry (VBM) in low-educated individuals with mild AD dementia compared to cognitively healthy people. Methods: Retrospective cohort of 24 adult volunteers with 4 years of schooling or less were included. Among them, 13 participants had a diagnosis of mild AD. Data obtained by VBM and FERT result were correlated. Results: AD group had a worse performance in the total FERT score (p <0.001). There was a statistically significant difference in the recognition of surprise, disgust and neutrality (p <0.001). A more intense and consistent correlation was observed between the volume of the Accumbens Area (AA) and FERT performance in the total group (r=0.817 and p <0.05). This correlation remained significant for emotion “disgust” only in the AD group (r=0.769 and p <0.05). Conclusion: We found a significant difference in the recognition of surprise, disgust and neutral emotions between groups. The brain region that was most associated with these emotions was the AA, with greater consistency in the difficulty in recognizing the emotion of disgust, in the AD.

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