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Deep brain stimulation of the entorhinal cortex modulates CA1 theta-gamma oscillations in mouse models of preclinical Alzheimer’s disease

Luo Yinpei, Sun Yuwei, Wen Huizhong, Wang Xing, Zheng Xiaolin, Ge Hongfei, Yin Yi, Wu Xiaoying, Li Weina, Hou Wensheng

Biocybernetics and Biomedical Engineering

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2023

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Vol. 43, no. 1

246--260

EN

Deep brain stimulation (DBS) is a neuromodulation method that modulates neuronal activity. A trend in the treatment of Alzheimer’s disease (AD) is targeting key points of neural circuits with DBS. Here, we explored the effects of DBS targeted to the entorhinal cortex (EC) on neurons in the hippocampal CA1 in a mouse model of preclinical AD. Specifically, we recorded field potential signals from CA1 in preclinical AD mice after DBS of the EC (1 h/day for 21 days of 100 lA, 90 ls, 10 Hz, biphasic square wave pulse) with in-vivo electrophysiology and evaluated corresponding changes in behavior with the open field task and Morris water maze (MWM) task. We also assessed changes in pathological markers and neurogenesis in the hippocampus with immunohistological staining. DBS of the EC increased theta and gamma power and modulated theta in the high gamma band (50-100 Hz) in preclinical AD mice. After DBS of the EC, these mice performed better in the MWM task and exhibited reduced deposition of beta-amyloid and neuronal changes including significant increases in proliferating neurons and immature neurons. This is the first study to target the EC with DBS and analyze resulting neural oscillations in the hippocampal CA1 in a model of preclinical AD. The findings support the use of DBS as a potential treatment for AD.

2

Comparative Analysis and Fusion of MRI and PET Images based on Wavelets for Clinical Diagnosis

Sebastian Jinu, King Gnana

International Journal of Electronics and Telecommunications

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2022

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Vol. 68. No. 4

867--873

EN

Nowadays, Medical imaging modalities like Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET), Single Photon Emission Tomography (SPECT), and Computed Tomography (CT) play a crucial role in clinical diagnosis and treatment planning. The images obtained from each of these modalities contain complementary information of the organ imaged. Image fusion algorithms are employed to bring all of this disparate information together into a single image, allowing doctors to diagnose disorders quickly. This paper proposes a novel technique for the fusion of MRI and PET images based on YUV color space and wavelet transform. Quality assessment based on entropy showed that the method can achieve promising results for medical image fusion. The paper has done a comparative analysis of the fusion of MRI and PET images using different wavelet families at various decomposition levels for the detection of brain tumors as well as Alzheimer’s disease. The quality assessment and visual analysis showed that the Dmey wavelet at decomposition level 3 is optimum for the fusion of MRI and PET images. This paper also compared the results of several fusion rules such as average, maximum, and minimum, finding that the maximum fusion rule outperformed the other two.

3

Application of Artificial Intelligence techniques for the detection of Alzheimer’s disease using structural MRI images

Zhao Xinxing, Ang Candice Ke En, Acharya U. Rajendra, Cheong Kang Hao

Biocybernetics and Biomedical Engineering

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2021

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Vol. 41, no. 2

456--473

EN

Alzheimer’s disease (AD) is an irreversible, progressive brain disorder that slowly destroys memory and thinking skills. It is one of the leading types of dementia for persons aged above 65 worldwide. In order to achieve accurate and timely diagnosis, and for detection of AD in its early stages, numerous Artificial Intelligence (AI) based Computer-aided Diagnostic (CAD) approaches have been proposed using data from brain imaging. In this paper, we review the recent application of AI based CAD systems on AD and its stages, with a particular focus on the use of structural MRI due to its cost effectiveness and lack of ionizing radiation. We will review important factors of different AI techniques pertinent to AD, summarize contributions from different research groups, critically discuss challenges involved and propose directions for future research. Ultimately, it would be ideal for development of a diagnostic framework that could be applicable to not only AD, but to different types of dementia as well in the future.

4

Dobry amyloid β? Właściwości chemiczne peptydów Aβ4-x wskazują na ich znaczenie biologiczne

Bal Wojciech

Wiadomości Chemiczne

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2019

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[Z] 73, 5-6

351--366

EN

Alzheimer’s Disease is a neurodegenerative condition, an irreversible progressive dementia caused by death of neurons in brain structures responsible for memory related processes. Despite many years of research and numerous trials, no therapy succeeded that could stop the development of this disease, which affects tens of millions of patients worldwide. The amyloid cascade prevails among a variety of possible mechanisms of its development proposed in the scientific literature. It proposes that death of neurons, preceded by dysfunction of their synaptic activity is caused by the incremental formation of structures (fibrils, oligomers) composed of Aβ peptides. In its copper variant the processes of aggregation and oxidative stress, causing the inflammation and neuronal damage are related to the formation of reactive Cu(II) complexes with Aβ peptides. Aβ peptides are a family of molecules with similar amino acid sequences, differing mainly by the presence of longer or shorter terminal sequences. Their physiological role of is unclear. Aβ1-42 and Aβ1-40 have been mostly studied, but most studies have ignored a very abundant N-terminally truncated species Aβ4-42. We recognized it, and more gene-rally the Aβ4-x peptide family as potentially strong Cu(II) ligands, due to the presence at their N-termini of the Phe-Arg-His amino acid sequence, comprising the ATCUN/NTS structural motif. This observation was followed by vigorous research performed in our laboratory. We studied the ability of Aβ4-x peptides to bind Cu(II) ions, their electrochemical properties and redox reactivity, interactions with proteins which bind copper under physiological conditions, their aggregation properties in the Cu(II) presence and susceptibility to proteolysis. Additionally, we investigated their interaction with a molecule of a therapeutic potential. We demonstrated that Aβ4-x peptides can be primary copper bin-ding agents in extracellular spaces in the brain, able to instantaneously intercept copper from Aβ1-x peptides studied so far. Cu(II) complexes of Aβ4-x peptides are highly resistant to oxidation and reduction, release copper ions to other molecules slowly and reluctantly, and do not produce reactive oxygen species. In accordance with these properties we proposed a physiological role for the Aβ4-42 peptide as a molecule cleansing the synaptic cleft from Cu2+ ions and thereby assuring the correct neurotransmission. This function can however be disturbed by an inappropriate pharmacological intervention. The results of studies of the effect of cupric ions on the aggregation and membrane interactions of the Aβ4-40 peptides suggest that copper can inhibit the Aβ4-x peptides toxicity, thereby providing an additional support for our concept. Studies of hydrolysis of Aβ peptides and properties of its products revealed a possibility for a significant role of short fragments in the brain copper physiology. Our hypothesis awaits verification by biological studies. The issue of metabolism of the studied complexes is a key issue remaining to be solved.

5

Współczesna diagnostyka laboratoryjna choroby Alzheimera

Beck Brygida, Siudek Bożena

Laboratorium Medyczne

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2019

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nr 1

40--44

PL

Wśród chorób i zaburzeń psychicznych dotykających starzejących się coraz bardziej populacji prawdziwym wyzwaniem są choroby otępienne, głównie choroba Alzheimera (AD). Od wielu lat trwają poszukiwania odpowiedniego biomarkera, który przyżyciowo umożliwiałby rozpoznanie AD. Obecnie niepodlegający dyskusji jest fakt, że w AD, nawet we wczesnym stadium, w płynie mózgowo-rdzeniowym stwierdza się obniżony poziom β-amyloidu i podwyższony poziom białka Tau. W związku z tym badanie płynu mózgowo-rdzeniowego zostało ujęte w kryteriach rozpoznawania AD jako jeden z testów, które należy rozważyć w diagnostyce.

EN

Among the diseases and mental disorders affecting the increasingly aging population, the real challenge is dementia, mainly Alzheimer’s disease (AD). For many years, the search for an appropriate biomarker which would enable the diagnosis of AD has been underway. Currently, the undebatable fact is that in AD, even at an early stage, cerebrospinal fluid has a reduced level of β-amyloid and an elevated level of Tau protein. Therefore, the cerebrospinal fluid testing has been included in the AD diagnostic criteria as one of the tests to be considered in the diagnostic process.

6

Coherence and phase synchrony analyses of EEG signals in Mild Cognitive Impairment (MCI): A study of functional brain connectivity

Handayani N., Haryanto F., Khotimah S. N., Arif I., Taruno W. P.

Polish Journal of Medical Physics and Engineering

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2018

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Vol. 24, Iss. 1

1--9

EN

This paper presents an EEG study for coherence and phase synchrony in mild cognitive impairment (MCI) subjects. MCI is characterized by cognitive decline, which is an early stage of Alzheimer’s disease (AD). AD is a neurodegenerative disorder with symptoms such as memory loss and cognitive impairment. EEG coherence is a statistical measure of correlation between signals from electrodes spatially separated on the scalp. The magnitude of phase synchrony is expressed in the phase locking value (PLV), a statistical measure of neuronal connectivity in the human brain. Brain signals were recorded using an Emotiv Epoc 14-channel wireless EEG at a sampling frequency of 128 Hz. In this study, we used 22 elderly subjects consisted of 10 MCI subjects and 12 healthy subjects as control group. The coherence between each electrode pair was measured for all frequency bands (delta, theta, alpha and beta). In the MCI subjects, the value of coherence and phase synchrony was generally lower than in the healthy subjects especially in the beta frequency. A decline of intrahemisphere coherence in the MCI subjects occurred in the left temporo-parietal-occipital region. The pattern of decline in MCI coherence is associated with decreased cholinergic connectivity along the path that connects the temporal, occipital, and parietal areas of the brain to the frontal area of the brain. EEG coherence and phase synchrony are able to distinguish persons who suffer AD in the early stages from healthy elderly subjects.

7

Texture and gene expression analysis of the MRI brain in detection of Alzheimer’s disease

Bustamam A., Sarwinda D., Ardenaswari G.

Journal of Artificial Intelligence and Soft Computing Research

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2018

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Vol. 8, No. 2

111--120

EN

Alzheimer’s disease is a type of dementia that can cause problems with human memory, thinking and behavior. This disease causes cell death and nerve tissue damage in the brain. The brain damage can be detected using brain volume, whole brain form, and genetic testing. In this research, we propose texture analysis of the brain and genomic analysis to detect Alzheimer’s disease. 3D MRI images were chosen to analyze the texture of the brain, and microarray data were chosen to analyze gene expression. We classified Alzheimer’s disease into three types: Alzheimer’s, Mild Cognitive Impairment (MCI), and Normal. In this study, texture analysis was carried out by using the Advanced Local Binary Pattern (ALBP) and the Gray Level Co-occurrence Matrix (GLCM). We also propose the bi-clustering method to analyze microarray data. The experimental results from texture analysis show that ALBP had better performance than GLCM in classification of Alzheimer’s disease. The ALBP method achieved an average value of accuracy of between 75% - 100% for binary classification of the whole brain data. Furthermore, Biclustering method with microarray data shows good performance gene expression, where this information show influence Alzheimer’s disease with total of bi-cluster is 6.

8

Znaczenie odpowiedniego źródła światła w różnych subpopulacjach. Osoby starsze

Łaszewska K.

Polish Journal for Sustainable Development

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2017

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T. 21, cz. 2

83--90

PL

Korzystanie z właściwego źródła światła sztucznego o spektrum bezpiecznym dla aparatu widzenia może wspomóc przezwyciężenie ograniczeń wynikających ze starzenia się oka, gdy do siatkówki dociera światło o znacznie niższym poziome natężenia. Najważniejszy zewnętrzny synchronizator rytmów okołodobowych, jakim jest zmiana światło-ciemność, odgrywa znamienną rolę dla osób starszych. Ma on znaczenie w wielu funkcjach ludzkiego organizmu: synchronizacja rytmu biologicznego z 24-godzinnym dniem solarnym, polepszenie jakości snu, obniżenie poziomu senności i zmęczenia, koordynacja ruchowa w prewencji upadków, polepszenie funkcji poznawczych oraz zapobieganie pojawianiu się agresji. Opracowanie odpowiedniego źródła światła sztucznego stanowi zatem ważkie zagadnienie dla polskiego społeczeństwa, w którym liczba osób starszych sukcesywnie wzrasta.

EN

24-hr solar day, improve sleep quality, reduce sleepiness and fatigue level, increase postural stability and reduce falls risk, improve cognitive functions and reduce aggression risks. The preparation of appropriate artificial light source for older adults is an essential issue for the Polish and other populations, where the amount of older people increases rapidly in nowadays.