Yazar "Bayraktaroglu, Zubeyir" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • [ X ]
    Öğe
    A structural and resting-state functional connectivity investigation of the pulvinar in elderly individuals and Alzheimer's disease patients
    (Wiley, 2023) Velioglu, Halil Aziz; Ayyildiz, Behcet; Ayyildiz, Sevilay; Sutcubasi, Bernis; Hanoglu, Lutfu; Bayraktaroglu, Zubeyir; Yulug, Burak
    In Alzheimer's disease (AD), structural and functional changes in the brain may give rise to disruption of specific cognitive functions. The aim of this study is to investigate the functional connectivity alterations in the pulvinar's subdivisions and total pulvinar voxel-based morphometry (VBM) changes in individuals with AD and healthy controls. A seed-based functional connectivity analysis was applied to the anterior, inferior, lateral, and medial pulvinar in each hemisphere. Furthermore, VBM analysis was carried out to compare gray matter (GM) volume differences in the pulvinar and thalamus between the two groups. Connectivity analysis revealed that the pulvinar subdivisions had decreased connectivity in individuals with AD. In addition, the pulvinar and thalamus in each hemisphere were significantly smaller in the AD group. The pulvinar may have a role in AD-related cognitive impairments and the intrinsic connectivity network changes and GM loss in pulvinar subdivisions suggest the cognitive deterioration occurring in those with AD. HighlightsThe pulvinar may play a role in pathophysiology of cognitive impairments in those with Alzheimer's disease (AD).Decreased structural volume and functional connectivity were found in patients with AD.The inferior pulvinar is functionally the most affected subdivision by AD compared to the others.
  • [ X ]
    Öğe
    Left lateral parietal rTMS improves cognition and modulates resting brain connectivity in patients with Alzheimer?s disease: Possible role of BDNF and oxidative stress
    (Academic Press Inc Elsevier Science, 2021) Velioglu, Halil Aziz; Hanoglu, Lutfu; Bayraktaroglu, Zubeyir; Toprak, Guven; Guler, Eray Metin; Bektay, Muhammed Yunus; Mutlu-Burnaz, Ozlem
    Repetitive Transcranial Magnetic Stimulation (rTMS) is a non-invasive neuromodulation technique which is increasingly used for cognitive impairment in Alzheimer?s Disease (AD). Although rTMS has been shown to modify Brain-Derived Neurotrophic Factor (BDNF) and oxidative stress levels in many neurological and psychiatric diseases, there is still no study evaluating the relationship between memory performance, BDNF, oxidative stress, and resting brain connectivity following rTMS in Alzheimer?s patients. Furthermore, there are increasing clinical data showing that the stimulation of strategic brain regions may lead to more robust improvements in memory functions compared to conventional rTMS. In this study, we aimed to evaluate the possible disease-modifying effects of rTMS on the lateral parietal cortex in AD patients who have the highest connectivity with the hippocampus. To fill the mentioned research gaps, we have evaluated the relationships between resting-state Functional Magnetic Resonance Imaging (fMRI), cognitive scores, blood BDNF levels, and total oxidative/antioxidant status to explain the therapeutic and potential disease-modifying effects of rTMS which has been applied at 20 Hz frequencies for two weeks. Our results showed significantly increased visual recognition memory functions and clock drawing test scores which were associated with elevated peripheral BDNF levels, and decreased oxidant status after two weeks of left lateral parietal TMS stimulation. Clinically our findings suggest that the left parietal region targeted rTMS application leads to significant improvement in familiarity-based cognition associated with the network connections between the left parietal region and the hippocampus.
  • [ X ]
    Öğe
    Parietal memory network and memory encoding versus retrieval impairments in PD-MCI patients: A hippocampal volume and cortical thickness study
    (Wiley, 2024) Sahin, Serhat; Velioglu, Halil Aziz; Yulug, Burak; Bayraktaroglu, Zubeyir; Yildirim, Suleyman; Hanoglu, Lutfu
    Objective: The pathophysiology behind memory impairment in Parkinson's Disease Mild Cognitive Impairment (PD-MCI) is unclear. This study aims to investigate the hippocampal and cortical atrophy patterns in PD-MCI patients with different types of memory impairments, categorized as Retrieval Failure (RF) and Encoding Failure (EF). Methods: The study included 16 healthy controls (HC) and 34 PD-MCI patients, divided into RF (N = 18) and EF (N = 16) groups based on their Verbal Memory Processes Test (VMPT) scores, including spontaneous recall, recognition, and Index of Sensitivity to Cueing (ISC). Hippocampal subfields and cortical thicknesses were measured using the FreeSurfer software for automatic segmentation. Results: Compared to the HC group, the EF group exhibited significant atrophy in the left lateral occipital region and the right caudal middle frontal, superior temporal, and inferior temporal regions (p < 0.05). The RF group displayed significant atrophy in the left lateral occipital, middle temporal, and precentral regions, as well as the right pars orbitalis and superior frontal regions (p < 0.05). Hippocampal subfield analysis revealed distinct volume differences between HC-EF and RF-EF groups, with significant reductions in the CA1, CA3, and CA4 subregions in the EF group, but no differences between HC and RF groups (p > 0.05). Conclusion: Gray matter atrophy patterns differ in PD-MCI patients with encoding and retrieval memory impairments. The significant hippocampal atrophy in the EF group, particularly in the CA subregions, highlights its potential role in disease progression and memory decline. Additionally, the convergence of atrophy in the lateral occipital cortex across both RF and EF groups suggests the involvement of the Parietal Memory Network (PMN) in PD-related memory impairment.