Psikoloji Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/417
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Article Remembered or Forgotten Stimuli: a Functional Magnetic Resonance Imaging Study on the Effects of Emotion(Kare Publ, 2020) Kilic, Betul; Ozcelik, ErolObjective: The first aim of this study is to examine why emotional events enhance memory for preceding stimuli. The second goal is to identify brain regions associated with remembering and forgetting by finding brain activation differences during encoding of remembered and forgotten stimuli. The third goal is to examine which brain areas are activated when studying emotional pictures compared to neutral ones. Method: In each trial, a picture of an object followed by an emotional or neutral picture from the Turkish culture were presented to 15 volunteers. The effect of the succeeding pictures on the remembering of preceding stimuli was examined. The participants studied the stimuli in the magnetic resonance scanner and, meanwhile, brain images were taken. The memory performances of the participants were measured with the recognition test administered one week later. Results: Behavioral results suggest that emotion has no effect on memory for preceding stimuli. Functional magnetic resonance imaging results indicate that remembered stimuli compared to forgotten ones caused more activation in left inferior frontal gyrus and left superior medial gyrus. Emotional pictures create more activation in the - mid-temporal gyrus and supramarginal gyrus compared to neutral images. Conclusion: Brain structures in which activations are observed in remembered stimuli compared to forgotten ones (left inferior frontal gyrus and left superior medial gyrus) are responsible for the semantic elaboration and associative memory formation. Thus, it can be concluded that object pictures are remembered because they are processed more deeply. Besides, activations are observed in the areas known to be related to the processing of emotional face expressions when emotional and neutral pictures are compared.Article Sleep spindle-related electroencephalograph activity of young adults and its relation to cognitive functions(Ege Univ, 2019) Torun Yazıhan, Nakşidil; Yetkin, Sinan; Yazıhan, Nakşidil TorunObjective: Sleep spindles are phasic bursts of thalamocortical activity, typically defined as 11-16 Hz (in sigma frequency band) with a duration of 0.5 and 2 seconds. Spindles are most prominent during N2 sleep and are a defining feature of this stage. The aim of the present study was to investigate the association between spindle characteristics and cognitive functions of young adults. Methods:The study sample consisted of 17 healthy male subjects aged between 19 and 28 years.The participants had no medical or psychological conditions and were not taking any medications that might affect their sleep pattern and neuropsychological measurements. Polysomnography recordings were conducted from 22:30 to 07:00 hour for two subsequent nights. The first night was for adaptation to the laboratory conditions and to rule out sleep apnea syndrome and periodic leg movements. The second night was used to analyze macro and micro parameters of sleep. A neuropsychological test battery comprising the Serial Digit Learning Test, Raven Standard Progressive Matrices, Verbal Fluency Test,Trail Making A-B, and the Auditory Verbal Learning Test were administered before the second-night sleep session. Sleep spindles in all non-rapid eye movement stage 2 sleep were scored visually from C3-A2 electroencephalogram derivation after polysomnographic analysis was completed. Each 30-sec epoch was analyzed with a high-pass band filtered at 0.3 Hz, and a low-pass band filtered at 35 Hz. Spindle characteristics such as duration, amplitude, mean and peak frequencies were analyzed using the fast Fourier transform algorithm. The association between the characteristics of sleep spindles and the neuropsychological test scores were analyzed using Spearman correlations. Results: Significant positive correlations were found between spindle density and both verbal auditory learning performance and verbal fluency, cognitive flexibility, and semantic organization performances. The serial digit learning test was correlated positively with mean duration, mean frequency, and peak frequency of sleep spindles. Finally, the mean duration, and mean frequency of spindles were positively correlated with verbal fluency, cognitive flexibility, and semantic organization. Conclusion: The associations between spindle features and memory, verbal fluency, and verbal learning abilities were consistent with previous research findings suggesting that sleep spindles might be related to cognitive abilities and the potential to learn. In other words, it might be an indicator of the current level of aptitude for learning.Article Uyku ve Açık Bellek Arasındaki İlişki(Galenos Yayınevi, 2018) Torun Yazıhan, Nakşidil; Yetkin, SinanUyku fizyolojik olarak aktif bir süreç olup bilişsel süreçlere ilişkin fonksiyonu uzun zamandır bilinmektedir. Uykunun iki farklı aşamada bellek ile ilişkili olarak kritik olduğu bilinmektedir. Birincisi öğrenme öncesi olan bilginin kodlanması aşaması; ikincisi ise öğrenme gerçekleştikten sonra yeni bilgilerin kalıcılığıyla ilişkili olan konsolidasyon aşamasıdır. Konsolidasyonun belleğin pek çok formu için evrimsel olarak korunmuş uykunun bir fonksiyonu olduğu düşünülmektedir. Bu derleme yazısının amacı uykunun mikro ve makro yapıları ile açık-deklaratif bellek süreçlerinin ilişkisini araştıran başlıca çalışma bulgularını bir araya getirmektir. Öncelikle uyku tanımlanmış, sonrasında uykunun açık bellek konsolidasyonu sürecindeki özgün rolü açıklanmıştır. Bu bağlamda öne sürülen aktif sistem konsolidasyonu ve sinaptik homeostazis hipotezleri anlatılmıştır. Uyku deprivasyonunun açık bellek ve bilgi işleme süreçleri üzerine etkilerini araştıran çalışma sonuçları özetlenmiştir. Son olarak uykunun mikro yapısını oluşturan uyku iğciği ve yavaş dalga aktivitesinin bellek süreçleri üzerindeki rolü tartışılmıştır.Article Citation - WoS: 1Sürpriz Bir Eski/Yeni Tanıma Belleği Görevinde Yaşlı Yetişkinlerde Olumlu Kelimeler İçin Tepki Yanlılığı Değişimi: Bir Tesadüfi Kodlama Çalışması(Gunes Kitabevi Ltd Sti, 2017) Kaynak, Hande; Gökçay, DidemGiriş: Yaşlı bireylerin özellikle olumlu kelimeleri bellekte daha iyi tuttukları bilinmesine rağmen, duygunun iki boyutunun (olumluluk ve heyecan düzeyleri) tesadüfi kodlama yapılan tanıma belleği performansı üzerindeki etkisi hâlâ netlik kazanmamıştır. Araştırmanın amacı, tesadüfi kodlanan ve olumluluk (olumlu, olumsuz ve nötr) ve heyecan düzeyleri (yüksek ve düşük) değişimlenen kelimelerin tanıma belleği puanları (bellek doğruluğu ve tepki yanlılığı) üzerindeki etkisini, sürpriz bir eski/yeni tanıma belleği göreviyle incelemektir. Gereç ve Yöntem: Çalışmaya, 60 genç ve 53 yaşlı olmak üzere 113 gönüllü katılmıştır. İlk olarak, duygusal kelimeler bilgisayarda tek tek sunulmuş, tesadüfi kodlama yapması istenen katılımcılardan kelimelerin kaç sesli harften oluştuğunu belirtmesi istenmiştir. 30 dakikadan sonra, test aşamasına geçilmiş, çalışma aşamasına atıfta bulunarak daha önce gördükleri kelimeleri tanımaları yönünde yönerge sunulmuş, sürpriz bir eski/yeni tanıma göreviyle bellek performansı kaydedilmiştir. Bulgular: 2×3×2 son faktörde tekrar ölçümlü deney deseni kullanılmıştır. Bağımlı değişken, tanıma belleği puanları olup, Sinyal Belirleme Kuramı temel alınarak bellek doğruluğu ve tepki yanlılığı hesaplanmıştır. Varyans analizlerine göre, yaşlıların kelimelerin olumluluk düzeyi açısından bellek doğruluğu puanları değişmemekle birlikte, özellikle olumlu kelimelere karşı istatistiksel olarak anlamlı bir tepki yanlılığı gösterdikleri bulunmuştur. Sonuç: Yaşlılar olumsuz kelimelere nazaran olumlu kelimelere daha çok önem vermektedir. Kelimelerin çaba harcamadan, tesadüfi kodlandığı koşulda, yaşla birlikte ortaya çıkan bu farklılık, yaşlıların iyi olma hallerini korumak adına duygularını düzenlediklerini öne sürmektedir. Çalışmamız bellek performansı ölçümlerinde, yaşla ilişkili etkenlerin belirlenmesinin önemine dikkat çekmektedirArticle Citation - WoS: 1Citation - Scopus: 1Sleep Spindle-Related Electroencephalograph Activity of Young Adults and Its Relation To Cognitive Functions(Ege Univ, 2019) Yazihan, Naksidil Torun; Yetkin, SinanObjective: Sleep spindles are phasic bursts of thalamocortical activity, typically defined as 11-16 Hz (in sigma frequency band) with a duration of 0.5 and 2 seconds. Spindles are most prominent during N2 sleep and are a defining feature of this stage. The aim of the present study was to investigate the association between spindle characteristics and cognitive functions of young adults. Methods:The study sample consisted of 17 healthy male subjects aged between 19 and 28 years.The participants had no medical or psychological conditions and were not taking any medications that might affect their sleep pattern and neuropsychological measurements. Polysomnography recordings were conducted from 22:30 to 07:00 hour for two subsequent nights. The first night was for adaptation to the laboratory conditions and to rule out sleep apnea syndrome and periodic leg movements. The second night was used to analyze macro and micro parameters of sleep. A neuropsychological test battery comprising the Serial Digit Learning Test, Raven Standard Progressive Matrices, Verbal Fluency Test,Trail Making A-B, and the Auditory Verbal Learning Test were administered before the second-night sleep session. Sleep spindles in all non-rapid eye movement stage 2 sleep were scored visually from C3-A2 electroencephalogram derivation after polysomnographic analysis was completed. Each 30-sec epoch was analyzed with a high-pass band filtered at 0.3 Hz, and a low-pass band filtered at 35 Hz. Spindle characteristics such as duration, amplitude, mean and peak frequencies were analyzed using the fast Fourier transform algorithm. The association between the characteristics of sleep spindles and the neuropsychological test scores were analyzed using Spearman correlations. Results: Significant positive correlations were found between spindle density and both verbal auditory learning performance and verbal fluency, cognitive flexibility, and semantic organization performances. The serial digit learning test was correlated positively with mean duration, mean frequency, and peak frequency of sleep spindles. Finally, the mean duration, and mean frequency of spindles were positively correlated with verbal fluency, cognitive flexibility, and semantic organization. Conclusion: The associations between spindle features and memory, verbal fluency, and verbal learning abilities were consistent with previous research findings suggesting that sleep spindles might be related to cognitive abilities and the potential to learn. In other words, it might be an indicator of the current level of aptitude for learning.Article The Relationship Between Sleep and Declarative Memory(Galenos Publ House, 2018) Yazihan, Naksidil Torun; Yetkin, SinanSleep is a physiologically active process and the function of cognitive processes is known for a long time. It is also known that sleep has a crucial role in two distinct phases of memory. The first one is the information encoding phase which is prior to the learning process; and the second one is the consolidation phase which is related with the persistency of new information after learning occurs. Consolidation is thought as a function of evolutionarily preserved sleep for many forms of memory. The aim of this review is to get together the main study findings which investigating the relationship between the micro and macro structures of sleep and declarative memory processes. Firstly, definition of sleep is given, and then the specific role of sleep in declarative memory consolidation process is explained. In this context, the projected active system consolidation and synaptic homeostasis hypothesis are explicated. The study results investigating the effects of sleep deprivation on declarative memory and information processing phases are summarized. Finally, the role of sleep spindle and slow wave activity on memory processes, which make up the microstructure of sleep, is discussed.