Serhat Taslica

Brain asymmetry measurement using EMISU (embedded interactive stimulation unit) in applied brain biophysics

The basic motive to study the brain asymmetry using a dichotic paradigm, forced the authors to develop an interactive stimulus system, where not only the stimuli but also the responses could be interactively registered real time on to the EEG data. Therefore, an embedded interactive stimulation unit (EMISU) was constructed and applied in such a task, incorporating behavioral and evoked data from 20 volunteers (10 male, 10 female, 21.15 years). The results provided a significant factor of laterality in favor of right ear responses (p<0.001) and also proved the applicability of the proposed design.

The Effect of Appetitive Daytime Napping on Cognitive Functions

Ad dress for Cor res pon den ce/Ya z›fl ma Ad re si: Adile Öniz MD, Dokuz Eylül University Faculty of Medicine, Department of Biophysics, İzmir, Turkey Phone: +90 232 412 44 98 E-mail: adile.oniz@gmail.com ORCID-ID: orcid.org/0000-0002-6619-4106 Re cei ved/Ge liş Ta ri hi: 20.11.2017 Ac cep ted/Ka bul Ta ri hi: 12.08.2018 ©Copyright 2018 by Turkish Sleep Medicine Society / Journal of Turkish Sleep Medicine published by Galenos Publishing House. Amaç: Uyku ihtiyacı evrenseldir ve işlevi tam olarak açıklığa kavuşturulmamıştır. Gündüz uyarılmışlık hali öğleden sonra düşüşe geçer. Bu düşüşü önlemenin yöntemlerinden biri de gündüz uykusudur. Bu araştırmanın amacı, ikram uykusu olarak uygulanan 60 dakikalık gündüz uykusunun bilişsel performans üzerindeki etkilerinin incelenmesidir. Gereç ve Yöntem: Çalışma, Dokuz Eylül Üniversitesi Tıp Fakültesi, Biyofizik Anabilim Dalı Uyku Dinamiği Araştırma Laboratuvarı’nda gerçekleştirilmiştir. Farklı iki gün laboratuvara gelen katılımcılar bir gün uyumuş diğer gün ise kontrol grubuna dahil edilmiştir. Çalışmaya 1924 yaş arasında nörolojik, psikolojik, kronik hastalığı olmayan ve uyku bozukluğu tanısı almamış toplam 14 sağlıklı birey (5 erkek; ortalama yaş: 21,86±1,23 yıl) katılmıştır. Katılımcılar her iki koşul öncesinde normal uyku düzenlerinde uyumuşlardır. Uyku kaydının öncesinde katılımcılara çeşitli bilişsel testler uygulanmıştır. Uyku sırasında ise uyku/uyanıklık durumunu takip etmek amacıyla elektroensefalografiden yararlanılmıştır. Altmış dakikanın sonunda katılımcılar uyandırılmış ve sonrasında tekrar aynı testleri yapılmıştır. Uyku kaydının yapılmadığı kontrol gününde ise katılımcılara belirlenen anketler uygulanmıştır. Dinlenme süresi uyku süresinde olduğu gibi 60 dakika olarak belirlenmiştir. Bulgular: Araştırmada 14 sağlıklı bireyin gündüz uykusu ve kontrol günlerindeki bilişsel performansları ölçülmüştür. Katılımcılar ortalama 57,3 (±3,57) dakika uyumuşlardır. Katılımcıların gündüz uykusu ve kontrol günlerindeki N-Back, Psikomotor Vijilans testi ve Timewall testleri skorları incelendiğine uyku sonrası farklılaşma görülse de anlamlı fark bulunamamıştır. Sonuç: Gündüz uykusunun bilişsel fonksiyonlar üzerinde farklı etkileri bulunmaktadır. İlerleyen araştırmalarda yedekleme ve ikram gündüz uykusunun davranışsal ve uyku evreleri açısından elektrofizyolojik olarak değerlendirilmesi hedeflenmektedir. Anahtar Kelimeler: İkram gündüz uykusu, bilişsel fonksiyonlar, tepki süresi, performans Objective: The need for sleep is universal and its function is not completely clarified. Daytime alertness decreases after midday and one of the ways of preventing this decrease is daytime napping. The aim of this study is to investigate the effects 60-minutes appetitive daytime napping on cognitive performance. Materials and Methods: This study was carried out at Dokuz Eylül University Faculty of Medicine, Department of Biophysics Sleep Dynamics Research Laboratory. Participants who came to the sleep laboratory in two different days slept one day and the other day were included in the control group. A total of 14 healthy individuals between age of 19-24 (5 male; mean age: 21.86±1.23 years) without any neurological, psychological, chronic diseases, or sleep disorders were included in the study. Participants slept on their regular sleep pattern before both conditions. Various cognitive tests were administered to participants before sleep recordings. Electroencephalography was used on the purpose of following the sleep/wakefulness situation while sleeping. At the end of 60-minutes, the participants were woken up and after then same tests were performed again. On the control day, without sleep recording, determined questionnaires were applied to the participants. The resting period was set 60-minutes as it was during the sleeping period. Results: Cognitive performances of 14 participants on napping and control conditions were measured. The average duration of sleep was 57.3 (±3.57) minutes. Participants’ scores of N-Back, Psychomotor Vijilans test, and Timewall tests on both conditions were examined. Although there were differences in the scores they were not significant. Conclusion: Daytime napping has different effects on cognitive functions. In future studies, it is aimed that the evaluation of the replacement and appetitive daytime napping in terms of the behavioral and sleep stages as electrophysiologically.

Brain morphometry and electrophysiological recordings in relation to illness duration in schizophrenia

Schizophrenia has been recently increasingly linked with a number of structural brain morphological changes which can be associated with functional deficiencies. The aim of this study is to relate electrophysiological changes with structural changes of Heschls gyrus (HG) volume in schizophrenia. Fifteen schizophrenia patients were compared with control group by magnetic resonance imaging (MRI) volumetry and auditory evoked potentials. A significantly lower bilateral HG volumes and a significantly lower global field power value of the N1P2 component were detected in the schizophrenia group. The auditory evoked potentials have been used as a functional correlate that displayed a significant amplitude reduction that matched the reduction in the HG volume with the chronicity of the disease. This trend may be utilized as a vehicle to assess follow-up of the disorder by means of MRI and electrophysiology.

Comparison of soprano and baritone dichotic listening test scores between genders: Preliminary results

Perception of voices of different genders by male and female individuals is in the research scope of many science areas. In this study, consonant-vowel syllables vocalized by baritone and soprano are presented to participants separately in the same session. In the dichotic application, homonymous or heteronymous syllable combinations are presented to each ear simultaneously. Participants are asked to indicate the syllable that they hear dominantly. For baritone and soprano voices, 36 syllable combinations are presented to 17 healthy subjects (8 females, age: 21.43) in three different conditions: when no attention is directed to any ear (non-forced/NF), when attention is directed to left ear (forced left ear attention/FL), and when attention is directed to right ear (forced right ear attention/FR). In NF condition, male and female subjects had high right ear advantage (REA) for both baritone and soprano voices. In FL condition, male and female subjects had high left ear advantage (LEA). In FR condition, REA was higher. Furthermore, REA score of males when soprano voice was presented was higher than the scores when baritone voice was presented, while females had higher REA scores when baritone voice was presented. To sum up, soprano and baritone voice presentation in dichotic listening test results in right ear preference in NF and FR conditions and left ear preference in FL condition. However, in FR condition REA is increased male and female subjects respond differently to baritone voices such that voice of opposite sex has higher advantage. Additionally, in FL and FR condition, that are indicators of attention, female subjects had better results than males. In further periods of the study, consistency of these results will be tested by increasing participant numbers.