Is Anterior Communicating Artery Syndrome Related to Fornix Lesions?

Molino, Ivana; Cavaliere, Carlo; Salvatore, Elena; Quarantelli, Mario; Colucci, Luisa; Fasanaro, Angiola Maria

doi:10.3233/jad-132648

Cited by 10 publications

(9 citation statements)

References 30 publications

(30 reference statements)

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“…Rather, clinically relevant imaging signs must provide clues that can be used to separate AD from other diseases that cause memory impairment. Indeed, the fornix might be affected by tumors, infections, inflammations (Yamamoto et al, 1990), metabolic abnormalities, vascular diseases (Molino et al, 2014), malformations, trauma, and hydrocephalus (Hattori et al, 2012) (for review, Thomas et al, 2011). Psychiatric diseases, such as schizophrenia and bipolar affective disorder (Oertel-Knöchel et al, 2014), or medical conditions, such as heart failure (Wu et al, 2007), also cause damage in the fornix.…”

Section: Clinical Applications Of the Findings Seen In The Fornixmentioning

confidence: 99%

Alzheimerâ€™s disease and the fornix

Oishi

2014

Front. Aging Neurosci.

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Alzheimer’s disease (AD) is the most common form of neurodegenerative dementia. Researchers have long been focused on the cortical pathology of AD, since the most important pathologic features are the senile plaques found in the cortex, and the neurofibrillary tangles and neuronal loss that begin in the entorhinal cortex and the hippocampus. In addition to these gray matter (GM) structures, histopathological studies indicate that the white matter (WM) is also a good target for both the early diagnosis of AD and for monitoring disease progression. The fornix is a WM bundle that constitutes a core element of the limbic circuits, and is one of the most important anatomical structures related to memory. Functional and anatomical features of the fornix have naturally captured researchers’ attention as possible diagnostic and prognostic markers of AD. Indeed, neurodegeneration of the fornix has been histologically observed in AD, and growing evidence indicates that the alterations seen in the fornix are potentially a good marker to predict future conversion from mild cognitive impairment (MCI) to AD, and even from cognitively normal individuals to AD. The degree of alteration is correlated with the degree of memory impairment, indicating the potential for the use of the fornix as a functional marker. Moreover, there have been attempts to stimulate the fornix using deep brain stimulation (DBS) to augment cognitive function in AD, and ongoing research has suggested positive effects of DBS on brain glucose metabolism in AD patients. On the other hand, disease specificity for fornix degeneration, methodologies to evaluate fornix degeneration, and the clinical significance of the fornix DBS, especially for the long-term impact on the quality of life, are mostly unknown and need to be elucidated.

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Section: Clinical Applications Of the Findings Seen In The Fornixmentioning

confidence: 99%

Alzheimerâ€™s disease and the fornix

Oishi

2014

Front. Aging Neurosci.

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“…White matter hyperintensities of presumed vascular origin (WMH), are divided into periventricular (PWMH) and deep (DWMH) and assessed by a visual rating scale (Fazekas score), commonly used in clinical settings ( Fazekas et al, 1987 ). For the statistical analysis of cortical thickness, we chose a Bayesian approach that is thought to be prudent, preventing the overestimation of evidence in favor of an effect ( Molino et al, 2014 ). We thus used a Bayesian inferential method (SingleBayes.exe) ( Crawford and Garthwaite, 2007 ) that allows testing if the patient’s values are significantly above (or below) the respective values of a small control sample.…”

Section: Introductionmentioning

confidence: 99%

Fronto-Temporal Circuits in Musical Hallucinations: A PET-MR Case Study

Cavaliere

Longarzo

Orsini

et al. 2018

Front. Hum. Neurosci.

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The aim of the study is to investigate morphofunctional circuits underlying musical hallucinations (MH) in a 72-years old female that underwent a simultaneous 18fluoredeoxyglucose positron emission tomography (PET) and advanced magnetic resonance (MR) exam. This represents a particular case of MH occurred in an healthy subject, not displaying neurological or psychopathological disorders, and studied simultaneously with a multimodal approach. For the resting-state fMRI analysis a seed to seed approach was chosen. For the task-based fMRI, 4 different auditory stimuli were presented. Imaging findings were compared with data obtained by ten healthy controls matched for age and sex. Neuropsychological evaluation and questionnaires investigating depression and anxiety were also administered. PET findings showed hypermetabolism of: superior temporal gyri, anterior cingulate, left orbital frontal, and medial temporal cortices. Structural MRI did not show macroscopical lesions except for gliotic spots along the uncinate fascicle pathways with an increased cortical thickness for the right orbitofrontal cortex (p = 0.003). DTI showed increased fractional anisotropy values in the left uncinate fascicle, when compared to controls (p = 0.04). Resting-state fMRI showed increased functional connectivity between the left inferior frontal gyrus and the left temporal fusiform cortex (p = 0.01). Task-based fMRI confirmed PET findings showing an increased activation of the superior temporal gyrus in all the auditory tasks except for the monotone stimulus, with a significant activation of the left orbital frontal cortex only during the song in foreign language, object of MH. Results on cognitive test did not show cognitive impairment, excepting for the performance on Frontal Assessment Battery where the patient fails in the cognitive domains of conceptualization, sensitive to interference, and inhibitory control. The subject did not show depressive or anxiety symptoms. Summarizing, multimodal imaging analyses in the MH case showed a microstructural alteration of the left uncinate fascicle paralleled by an increased metabolism and functional connectivity of cortical regions that receive left uncinate projections (orbital frontal cortex, and medial temporal cortex). This alteration of fronto-hyppocampal circuits could be responsible of retrieval of known songs even in the absence of real stimuli.

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“…With structural and microstructural images, in order to test differences in brain volume, cortical thickness, parcels area and diffusion parameters, Bayesian statistical comparison was performed with “Singlebayes” software [ 28 , 29 ].…”

Section: Methodsmentioning

confidence: 99%

Microstructural Changes in Motor Functional Conversion Disorder: Multimodal Imaging Approach on a Case

et al. 2020

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Background: Functional motor conversion disorders are characterized by neurological symptoms unrelated to brain structural lesions. The present study was conducted on a woman presenting motor symptoms causing motor dysfunction, using advanced multimodal neuroimaging techniques, electrophysiological and neuropsychological assessment. Methods. The patient underwent fluorodeoxyglucose-positron emission tomography-computed tomography (FDG-PET-CT) and functional magnetic resonance imaging (fMRI) with both task and resting-state paradigms and was compared with 11 healthy matched controls. To test differences in structural parameters, Bayesian comparison was performed. To test differences in functional parameters, a first- and second-level analysis was performed in task fMRI, while a seed-to-seed analysis to evaluate the connections between brain regions and identify intersubject variations was performed in resting-state fMRI. Results. FDG-PET showed two patterns of brain metabolism, involving the cortical and subcortical structures. Regarding the diffusion data, microstructural parameters were altered for U-shape fibers for the hand and feet regions. Resting-state analysis showed hypoconnectivity between the parahippocampal and superior temporal gyrus. Neurophysiological assessment showed no alterations. Finally, an initial cognitive impairment was observed, paralleled by an anxiety and mild depressive state. Conclusions. While we confirmed no structural alterations sustaining this functional motor disorder, we report microstructural changes in sensory–motor integration for both the hand and feet regions that could functionally support clinical manifestations.

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Is Anterior Communicating Artery Syndrome Related to Fornix Lesions?

Cited by 10 publications

References 30 publications

Alzheimerâ€™s disease and the fornix

Alzheimerâ€™s disease and the fornix

Fronto-Temporal Circuits in Musical Hallucinations: A PET-MR Case Study

Microstructural Changes in Motor Functional Conversion Disorder: Multimodal Imaging Approach on a Case

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