Canan Basar-Eroglu

Canan Basar-Eroglu
Izmir University of Economics · Department of Psychology

Prof. Dr.

About

189
Publications
16,772
Reads
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7,977
Citations
Citations since 2017
10 Research Items
1990 Citations
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20172018201920202021202220230100200300
20172018201920202021202220230100200300
20172018201920202021202220230100200300

Publications

Publications (189)
Article
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., Ad...
Poster
Sustained Attention has a crucial meaning in our life from basic task to complicated and can be measured experimentally with Sustained Attention to Response Task (SART). SART has been using with EEG to measure psychological and cognitive processes for years. One of research area is examining the ERPs and EROs components with SART. The aim of our re...
Presentation
Multistable perception has been studied by scientists and philosophers for over 200 years. Wealth of this literature provided many interesting findings, most of which are still to be studied with neuroimaging techniques. One of such findings is the age-related decrease in perceptual reversal rates. This thesis aimed to identify the changes in theta...
Article
Objective Coherent object perception in patients with schizophrenia is known to be impaired. Oscillatory brain dynamics constitute a fundamental mechanism for the coordinated communication of neural circuits. Such dynamics have been proposed to reflect impaired spatio-temporal integration of sensory and cognitive processes during object perception...
Article
Full-text available
Event-related potentials (ERPs) and oscillations (EROs) are reliable measures of cognition, but they require time-locked electroencephalographic (EEG) data to repetitive triggers that are not available in continuous sensory input streams. However, such real-life-like stimulation by videos or virtual-reality environments may serve as powerful means...
Article
Full-text available
Adolescents are easily distracted by novel items than adults. Maturation of the frontal cortex and its integration into widely distributed brain networks may result in diminishing distractibility with the transition into young adulthood. The aim of this study was to investigate maturational changes of brain activity during novelty processing. We hy...
Article
Objectives: This study compared sensorimotor alpha and beta brain oscillations in young and older adults, to examine their functional distinctness and susceptibility to aging. Methods: Electroencephalographic data were compared between young (age 23±3) and older adults (age 64±7) in terms of event-related spectral perturbation in alpha and beta...
Article
Objective: During adolescence event-related modulations of the neural response may increase. For slow event-related components, such as the P3, this developmental change may be masked due to increased amplitude levels of ongoing delta and theta oscillations in adolescents. Methods: In a cross-sectional study design, EEG was measured in 51 partic...
Article
The research related to brain oscillations and their connectivity is in a new take-off trend including the applications in neuropsychiatric diseases. What is the best strategy to learn about functional correlation of oscillations? In this report, we emphasize combined application of several analytical methods as power spectra, adaptive filtering o...
Article
Patients with schizophrenia are impaired in maintaining coherent perceptual experiences. This is reflected in the oscillatory theta response and can be investigated by visual illusions. Ambiguous stimuli elicit illusory perceptual switches while the stimulus remains unchanged. Theta responses elicited by an ambiguous and unambiguous control stimulu...
Article
Schizophrenia is a complex mental disorder with impairments in integrating sensory and cognitive functions, leading to severe problems in coherent perception. This impairment might be accelerated during multistable perception. Multistable perception is a phenomenon, where a visual pattern gives rise to at least two different perceptual representati...
Article
The research related to brain oscillations and their connectivity is in a new take-off trend including the applications in neuropsychiatric diseases. What is the best strategy to learn about functional correlation of oscillations? In this report, we emphasize combined application of several analytical methods as power spectra, adaptive filtering of...
Article
The prefrontal cortex (PFC) is considered to be the primary source of attentional control during elementary visual processing as exemplified in perceptual ambiguity. Assuming that multistable perception activates a fronto-parietal network, we contrast the results of mature and developing cognitive systems to deduce the developmental status of under...
Article
The application of the concept and methods of brain oscillations has been an important research area in neurosciences. In the last decades, besides the application in cognitive processes, the study of changes in brain oscillations in diseases has also became an important focal point of research. In the present paper, some remarkable examples in thr...
Conference Paper
Full-text available
Background / Purpose: The aim of this study was to develop a method following the cognitive dynamics in the electroencephalogram (EEG) during video watching. Event related potentials (ERPs) were recorded under passive conditions by introducing temporal triggers in the visual stream that do not significantly interfere with the real-world like dyna...
Article
Object perception is driven by sensory information as well as expectations and prior experiences. The latter influence may increase when the sensory information is poor or inconclusive. Visual illusions, for example induced by ambiguous stimuli, provide a tool to investigate perceptual uncertainty, because ambiguous stimuli elicit switching between...
Chapter
Objective: Most of the work on disturbed oscillatory activity during auditory tasks in schizophrenia has focused on reduced gamma oscillations at fronto-central sites. Recent studies of our group, however, indicate a more general disturbance affecting the spatial distribution of oscillatory brain activity of gamma as well as slow frequencies, such...
Article
Brain oscillations have gained tremendous importance in neuroscience during recent decades as functional building blocks of sensory–cognitive processes. Research also shows that event-related oscillations (EROs) in “alpha,” “beta,” “gamma,” “delta,” and “theta” frequency windows are highly modified in pathological brains, especially in patients wit...
Article
Most of the work on disturbed oscillatory activity during auditory tasks in schizophrenia has focused on reduced gamma oscillations at fronto-central sites. Recent studies of our group, however, indicate a more general disturbance affecting the spatial distribution of oscillatory brain activity of gamma as well as slow frequencies, such as alpha os...
Article
Memory-guided decision making is dynamic and context-dependent, even though many studies describe an enhancement of the P3 for recognized items in memory tasks ("old-new effect"). This study utilized a delay-dependent working memory task during which decision making could be optimized by focusing attention on detected changes instead of recognized...
Article
Behavioral and electrophysiological data related to performance in an auditory Go/NoGo task were analyzed in young and older adults in the present study. Especially, differences in within-person variability in behavior and neural activity between young and older adults and changes in topography of slow event-related oscillations (EROs) were of inte...
Article
This study investigated changes in gamma oscillations during auditory sensory processing (auditory-evoked gamma responses, AEGR) and target detection (auditory event-related gamma responses, AERGR) in healthy controls (n=10) and patients with schizophrenia (n=10) using both single-trial and averaged time-frequency data analysis. The results show th...
Article
ERPs may be limited in validity when investigating inhibitory functions in later adulthood, as age-related increases in intraindividual variability and changes in EEG-oscillations are not considered. The present study compared averaged ERP peak and single trial time-frequency (TF) data analysis. Go/NoGo ERP waves amplitude/latency measures were com...
Article
Multistable visual perception refers to phenomena, in which one invariant stimulus pattern is perceived in at least two different, mutually exclusive ways. In this EEG study we differentiate between perceptual- and motor-related processes during perceptual reversals. Delta- and alpha-band activity was analyzed while participants answered to a perce...
Article
Many studies suggest that separate retinocortical channels with different conduction speeds transmit the information about high and low spatial frequencies (SF). Similarly, separate callosal channels may be responsible for the transfer of different SFs. To test this hypothesis, interhemispheric transfer time (IHTT) was estimated using visual evoked...
Article
A major challenge for developmental cognitive neuroscience is to understand how changes in cognitive functions related to aging are associated with changes in the neuronal information processing architecture. Previous studies on EEG event-related brain oscillations suggest functional changes in alpha-bands with age during sensory and memory tasks....
Article
In the present study we used a simple visual evoked potential and a visual oddball paradigm to investigate alterations in the temporal integration of different frequency components such as alpha and theta oscillations in patients with schizophrenia. We found that neither the amplitude enhancement after stimulus onset nor the intertrial phase cohere...
Article
Amplitude reduction of the oddball P3 wave is a well-replicated but non-specific finding of schizophrenia. The time-frequency analysis of single-trial ERP data allows to specify in a reliable manner whether the P3 reduction in schizophrenia is due to the decreased P3 response in single trials or due to the inter-trial variability in the timing of t...
Article
Deficits in sustained attention and vigilance were assessed for oscillatory delta, theta, alpha, and gamma EEG activity during an auditory continuous performance task in patients with schizophrenia and healthy controls by quantifying peak-to-peak amplitudes of averaged and single-trial data. Averaged data indicated significantly reduced amplitudes...
Article
Impairments in emotional recognition have been consistently reported in schizophrenic patients. The main aim of the present study was to evaluate time-sequenced responses in ERPs and event-related oscillations during emotional recognition of happiness and fear compared to facial identity recognition in schizophrenic patients (SCH) versus healthy co...
Article
Previous studies have shown a close interrelation between emotional processing and memory processes using facial stimuli and applying the concept of oscillatory brain dynamics. Amending prior findings the influence of neural correlates related to the emotional state termed "romantic love" was investigated. Specifically, the effect of feelings of lo...
Article
Patients in a vegetative state (VS) show a spontaneous wake-sleep-cycle but no evidence of awareness, of interaction with the environment, voluntary action, and language comprehension. The neuropathological conditions underlying VS are still not fully understood. In this retrospective study we focused on VS due to hypoxia and used SPECT, VEP and ev...
Article
The aim of the current study was to investigate the prepulse inhibition (PPI) of auditory-evoked delta, alpha, and gamma oscillations. Concurrent EEG and auditory startle reflex were recorded from 15 healthy participants during Pulse-Alone and Prepulse+Pulse trials with 60, 120, and 240 ms prepulse-pulse intervals. A significant PPI of the startle...
Article
The present report introduces, as a first study, the concept and methods of oscillatory brain dynamics to analyze well-known (familiar) and unfamiliar face processing in the 800 ms following a face presentation. We analyzed event-related oscillations in young, healthy subjects (N=26) by using three types of stimulation: (1) a simple light signal, (...
Article
Recent reports show that the capability of neural networks supporting high-frequency synchronization is reduced in the brain of schizophrenia patients. Specifically, deficits in gamma activity have been shown in schizophrenia patients during perception and simple cognitive tasks. However little is known about alterations in gamma responses during c...
Article
This study investigated event-related oscillations associated with a Simon task in 11 Parkinson's disease patients, 11 age-matched, and 11 young participants. During this task, participants respond faster when the relative spatial positions of stimulus and response match (no response conflict exists) than when they do not match (response conflict e...
Article
Reversible figures such as the Necker cube make up a well-known class of visual phenomena in which an invariant stimulus pattern gives rise to at least two different perceptual interpretations. Former EEG studies of our research group demonstrated a reversal-related delta response and a frontal enhancement of gamma activity during multistable perce...
Article
The aim of the current study was to investigate the auditory-evoked theta oscillatory activity associated with prepulse inhibition (PPI) of the startle reflex in healthy humans. Concurrent electroencephalogram (EEG) and auditory startle reflex were recorded from 19 healthy controls during Pulse-Alone and Prepulse + Pulse trials with 60, 120, and 24...
Article
Altered frontal lobe activity and executive control associated with working memory (WM) dysfunction are recognized as core deficits in schizophrenia. These impairments have been discussed as being associated with deficits in self-regulated action monitoring and anticipatory action plan generation. To study electrophysiological correlates of executi...
Article
The aim of the present study was to investigate alterations in brain oscillatory activity during transient intentional encoding of abstract novel shapes in patients with Parkinson's disease (PD). Combined time-frequency analyses of alpha and theta power revealed a clear dissociation between PD patients (N=10) and age-matched healthy controls (N=10)...
Article
2 Hanse-Wissenschaftskolleg, Delmenhorst Als Hans Berger 1929 das menschliche EEG entdeckt hatte, war es eines seiner vordringlichen Ziele, EEG-Oszillationen unterschiedlicher Frequenz mit ver-schiedenen kognitiven Prozessen in Verbindung zu bringen. Heute zählen EEG-Ableitungen zu den etab-lierten Methoden sowohl innerhalb der kognitiven Neurowiss...
Article
Working memory (WM) has three cognitive components, i.e. encoding and retaining of information, and the retrieval of stored expressions. It is accepted that the left frontal slow wave negativity is an indicator of the functions of working memory. This study aims to investigate the encoded functions of working memory through the variations in the am...
Article
This report presents an analysis of the brain's beta oscillations in face recognition. We performed experiments on 26 subjects with a strategy consisting of two types of stimulations: (1) the picture of an elder anonymous lady (unknown face) and (2) the picture of the subject's own grandmother (known face). The subjects were healthy, young people b...
Article
A study to estimate the percentage of callosal fibers of different fibers of different diameters activated by visual stimuli by comparing amplitudes of visually evoked potentials (VEP) at different frequency bands was discussed. The study gave an idea on how to use time-frequency analysis and cross correlation of signals in the determination of int...
Article
Full-text available
The present report describes the dynamic foundations of long-standing experimental work in the field of oscillatory dynamics in the human and animal brain. It aims to show the role of multiple oscillations in the integrative brain function, memory, and complex perception by a recently introduced conceptional framework: the super-synergy in the whol...
Article
Full-text available
This paper presents superbinding, a concept that represents integrative oscillatory dynamics over the time and space axes. Principle of superposition describes integration over the temporal axis; selectively distributed and selectively coherent oscillatory neural populations describe integration over the spatial axis. Integrative activity is a func...
Article
The present study aimed to describe the effect of aging on single-trial visual alpha responses. Visual evoked potentials were recorded at F3, Cz, P3, and O1 in 12 young (20-30-year-olds) and in 10 middle-aged adults (50-55-year-olds). Slow (7-10 Hz) and fast (10-15 Hz) alpha frequency bands were analyzed. Three parameters of single alpha responses...
Article
In this ERP study we use a verbal "two-back" paradigm to investigate working memory (WM). We compare (1) a recognition control task, (2) a task with target words repeated only in critical positions, and (3) a task with words repeated in critical and in noncritical positions. Response time and omissions increased significantly from task 1 to task 3....
Article
We compared schizophrenic patients and control subjects in a working memory (WM) paradigm for self-executed movements, evaluating behavioral and ERP data. The paradigm consisted of a control task, an easy WM task requiring subjects to remember the last movement and a hard WM task requiring subjects to remember the last two movements and to update t...
Article
In two former studies our research group reported frontal gamma-band enhancement during multistable visual perception and reversal rate dependent differences in the gamma-band. In these studies, a dynamic reversible figure was used which was based on the phenomenon of apparent motion. The aim of this study was to examine whether the results obtaine...
Article
The EEG consists of the activity of an ensemble of generators producing rhythmic activity in several frequency ranges. These oscillators are active usually in a random way. However, by application of sensory stimulation these generators are coupled and act together in a coherent way. This synchronization and enhancement of EEG activity gives rise t...
Article
Experiments from the cat brain demonstrate that gamma responses can be recorded in cortex, hippocampus, cerebellum, formatio reticularis and thalamus, independent of the mode of sensory stimulation. These results support the hypothesis of a selectively distributed gamma system of the brain.
Article
Full-text available
This paper deals with the functional correlates of the gamma response of the brain. A critical review of the literature findings reveals the existence of two types of gamma responses: an early gamma that fulfills sensory functions and a late gamma that fulfills perceptual-cognitive functions. However, even the early gamma shows individual differenc...
Article
This report provides a synthesis of results in both cat and human brains in order to point out the importance of theta responses during cognitive processes and P300 paradigms. The unique features of this report consisted of the fact that human and cat data during several cognitive paradigms were compared. The results open the way to formulate the s...
Article
This report describes the frequency response of the oddball paradigm upon auditory stimuli. Other reports related to wavelet analysis of the same ERPs (Demiralp et al., 1999) and the application of visual signals (Schürmann et al., this volume) indicate that the P300 response has a dominant delta response oscillation, independent of the modality of...
Article
The comparative wavelet analysis presented in details by Demiralp et al. (1999), Ademoglu (1995) and by Başar et al. (2001) will be now applied to oddball P300 results (see Başar-Eroglu et al., 2001). The results obtained basically confirm those obtained by using adaptive digital filtering: The delta response dominates the P300 potential while the...
Article
Visual P300 responses were recorded by using checkerboard-type stimuli. (1) High amplitude P300-delta responses were visible even in single trial ERPs. (2) An algorithm for efficient selection of P300 single trials (based on evaluation of delta responses) is introduced. (3) The 'universal' character of the P300-delta response demonstrated in this r...
Article
The increased interest in gamma oscillations, now widely regarded as functionally relevant signals of the brain, underlines the importance of the concept of event-related oscillations for bridging the gap between single neurons and neural assemblies. Taking this concept further, we review experiments showing that oscillatory phenomena such as alpha...
Article
In this study, we compared working memory (WM) functions for simple actions of healthy subjects and schizophrenic patients by means of behavioral and ERP measures. Healthy subjects showed a large frontal N2 amplitude in the hard WM task with updating demands of temporal sequence, but not in the easy WM and the control task. Schizophrenic patients h...