Browsing by Author "Hunerli-Gunduz, Duygu"

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Citation - WoS: 12
Citation - Scopus: 12
Reduced Power and Phase-Locking Values Were Accompanied by Thalamus, Putamen, and Hippocampus Atrophy in Parkinson?s Disease With Mild Cognitive Impairment: an Event-Related Oscillation Study
(Elsevier Science Inc, 2023) Hunerli-Gunduz, Duygu; Isbitiren, Yagmur Ozbek; Uzunlar, Hakan; Cavusoglu, Berrin; Colakoglu, Berril Donmez; Adag, Emel; Yener, Görsev
Parkinson's disease (PD) is a multifaceted neurodegenerative disorder accompanied by mild cognitive im-pairment (MCI) as a crucial nonmotor manifestation. Event-related oscillations (EROs) are suggested to re-flect cognitive status associated with subcortical structures in neurodegenerative conditions. In this study, 36 individuals with PD-MCI and 32 PD-CN were compared with 60 healthy control (HC) participants us-ing visual EROs by measures of event-related spectral perturbation and inter-trial coherence, along with subcortical gray matter volumes based on the FIRST algorithm. Cross-correlations among electrophysio-logical, neuropsychological, and structural parameters were investigated exploratively. Both PD-MCI and PD-CN patients had diminished delta and alpha phase-locking than HC, however, electrophysiological ab-normalities were more pronounced in PD-MCI over frontal, central, parietal, and temporal locations in almost all frequency bands, accompanied by bilateral thalamus, hippocampus, and right putamen atro-phy. PD-CN had lower hippocampal volumes than HC, without exhibiting any subcortical differences from PD-MCI. Lastly, EROs showed low-to-high correlations with structural and neuropsychological measures. These findings may highlight the complex interplay between electrophysiological, neuropsychological, and structural parameters in detected abnormalities of PD-CN and PD-MCI. (c) 2022 Elsevier Inc. All rights reserved.
Citation - WoS: 2
Citation - Scopus: 2
Taxonomically-Related Word Pairs Evoke Both N400 and Lpc at Long Soa in Turkish
(Springer/Plenum Publishers, 2022) Duzenli-Ozturk, Seren; Hunerli-Gunduz, Duygu; Emek-Savas, Derya Durusu; Olichney, John; Yener, Görsev; Ergenc, H. Iclal
Semantic priming in Turkish was examined in 36 right-handed healthy participants in a delayed lexical decision task via taxonomic relations using EEG. Prime-target relations included related- unrelated- and pseudo-words. Taxonomically related words at long stimulus onset asynchrony (SOA) were shown to modulate N400 and late positive component (LPC) amplitudes. N400 semantic priming effect in the time window of 300-500 ms was the largest for pseudo-words, intermediate for semantically-unrelated targets, and smallest for semantically-related targets as a reflection of lexical-semantic retrieval. This finding contributes to the ERP literature showing how remarkably universal the N400 brain potential is, with similar effects across languages and orthography. The ERP data also revealed different influences of related, unrelated, and pseudo-word conditions on the amplitude of the LPC. Attention scores and mean LPC amplitudes of related words in parietal region showed a moderate correlation, indicating LPC may be related to relationship-detection process.
Citation - WoS: 2
Citation - Scopus: 2
Telling Functional Networks Apart Using Ranked Network Features Stability
(Nature Portfolio, 2022) Zanin, Massimiliano; Guntekin, Bahar; Akturk, Tuba; Yildirim, Ebru; Yener, Görsev; Kiyi, Ilayda; Hunerli-Gunduz, Duygu
Over the past few years, it has become standard to describe brain anatomical and functional organisation in terms of complex networks, wherein single brain regions or modules and their connections are respectively identified with network nodes and the links connecting them. Often, the goal of a given study is not that of modelling brain activity but, more basically, to discriminate between experimental conditions or populations, thus to find a way to compute differences between them. This in turn involves two important aspects: defining discriminative features and quantifying differences between them. Here we show that the ranked dynamical stability of network features, from links or nodes to higher-level network properties, discriminates well between healthy brain activity and various pathological conditions. These easily computable properties, which constitute local but topographically aspecific aspects of brain activity, greatly simplify inter-network comparisons and spare the need for network pruning. Our results are discussed in terms of microstate stability. Some implications for functional brain activity are discussed.
Citation - WoS: 17
Citation - Scopus: 20
Treatment Effects on Event-Related Eeg Potentials and Oscillations in Alzheimer's Disease
(Elsevier, 2022) Yener, Görsev; Hunerli-Gunduz, Duygu; Yildirim, Ebru; Akturk, Tuba; Başar Eroğlu, Canan; Bonanni, Laura; Del Percio, Claudio
Alzheimer's disease dementia (ADD) is the most diffuse neurodegenerative disorder belonging to mild cognitive impairment (MCI) and dementia in old persons. This disease is provoked by an abnormal accumulation of amyloid-beta and tauopathy proteins in the brain. Very recently, the first disease-modifying drug has been licensed with reserve (i.e., Aducanumab). Therefore, there is a need to identify and use biomarkers probing the neurophysiological underpinnings of human cognitive functions to test the clinical efficacy of that drug. In this regard, event-related electroencephalographic potentials (ERPs) and oscillations (EROs) are promising candidates. Here, an Expert Panel from the Electrophysiology Professional Interest Area of the Alzheimer's Association and Global Brain Consortium reviewed the field literature on the effects of the most used symptomatic drug against ADD (i.e., Acetylcholinesterase inhibitors) on ERPs and EROs in ADD patients with MCI and dementia at the group level. The most convincing results were found in ADD patients. In those patients, Acetylcholinesterase inhibitors partially normalized ERP P300 peak latency and amplitude in oddball paradigms using visual stimuli. In these same paradigms, those drugs partially normalize ERO phase-locking at the theta band (4-7 Hz) and spectral coherence between electrode pairs at the gamma (around 40 Hz) band. These results are of great interest and may motivate multicentric, double-blind, randomized, and placebo-controlled clinical trials in MCI and ADD patients for final cross-validation.