Çalışma Belleğine Ait OİP Temelli Elektrofizyolojik Bulguların İncelenmesi
Uyaranların etkisi ile gözlemlenen Olaya İlişkin Potansiyel (OİP) bileşenleri çalışma belleği araştırmalarındaönemli bir yer tutmaktadır. Çalışma belleği temelde karmaşık bilişsel görevleri yürütme, bilgileri geçiciolarak saklama ve kullanma imkanı veren zihinsel bir süreç olarak bilinmektedir. Çalışmanın amacı;çalışma belleği kavramının, bilişsel süreçler sırasında beyinde oluşan elektriksel yanıtlar ile anlaşılmasınınsağlamasıdır. Araştırmaya Marmara Üniversitesi’nden toplamda 21 katılımcı yaş ortalaması 21 olan 1 kadınve yaş ortalaması 22.95 (SS= 5.549) olan 20 erkek sporcu katılmıştır. EEG kaydı 16 kanal Brain ProductsactiCAP ile 1000 Hz örneklem frekansında alınmıştır. N-geri görevi olarak katılımcılara LCD ekran aracılığıile siyah ekran üzerine beyaz fontlarla yazılmış 8 adet harf ( B, Q, X, F, M, K, H, R) rastgele ve bir sette 25harf olacak şekilde 8 set halinde gösterilmiştir. Deneyden toplanan verilerin analizleri için Brain ProductsAnalyzer, Matlab R2013 ve SPSS v17 paket programları kullanılmıştır. Verilerin istatistiksel analizi ÇokDeğişkenli Varyans Analizi (ANOVA) kullanılarak yapılmıştır. Çalışmanın elektrofizyolojik analizleri,ortalama güç değerleri kapsamında incelendiğinde frontal, santral, oksipital ve parietal alanda anlamlıfarklılıklar bulunmuştur (F=(2.19)=17.43; p=0.00). Ortalama zaman değerleri kapsamında incelendiğindeise yine frontal, santral, oksipital ve parietal alanda anlamlı farklılıklar bulunmuştur (F=(4,76)=10.07;p=0.00). Fakat ortalama frekans değerleri incelendiğinde anlamlı bir fark olmadığı görülmüştür.Katılımcıların uyaranlara karşı reaksiyon zamanları; basması gerekip bastığı (doğru durum) ve basmamasıgerekip bastığı (yanlış durum) şeklinde incelendiğinde basması gerekip bastığı durumun, basmamasıgerekip bastığı durumdan daha önce yaşandığı görülmüştür. Bu sonuçlar ışığında N-geri görevinin çalışmabelleği ve dikkat süreçlerini anlama konusunda kullanışlı bir araç olduğu düşünülmektedir.
Assesment of ERP Based Electrophysiological Findings of Working Memory
The Event Related Potential (ERP) components that are observed in response to the stimuli play animportant role in working memory research. The working memory is known as a mental process thatbasically allows the use of complex cognitive tasks, the ability to temporarily store and use information.The purpose of this study is to understand the concept of the working memory and electrical responsesof the brain during cognitive processes. A total of 21 participants from Marmara University, 1 female(mean age=21) and 20 male (mean age=22.95, SD=5.54) athletes voluntarily participated in the study. EEGrecordings were performed with 16 channel Brain Products actiCAP at 1000 Hz sampling frequency. 8letters (B, Q, X, F, M, K, H, R) written in white on a black screen were used as stimuli. All stimuli randomlypresented in 8 sets with each set consisting of 25 letters. An LCD screen was used as presentation apparatus.For the analysis of the data, Brain Products Analyzer, MatlabR2013 software program and SPSS17 packageprogram were used. Statistical analyzes of the data were done using Multivariate Analysis of Variance(ANOVA). Electrophysiological analysis of the study showed significant differences in frontal, central,occipital and parietal areas (F (2.19) = 17.43; p = 0.00). When the mean time values were examined,significant differences were found in frontal, central, occipital and parietal areas (F = (4.76) = 10.07; p =0.00). However, there was no significant difference in the mean frequency values. When the participants’reaction times were examined, it is found that they press the button faster for the stimuli they need topres (correct situation) then they fort he stimuli they should not pres (wrong situation). In light of theseresults, it is thought that the N-back task can provide a illuminating results to understand working memoryprocesses.
___
- Baddeley, A. (1992). Working memory. Science, 255(5044), 556-559.
- Bressler, S. L., & Ding, M. (2002). Event-related potentials. The handbook of brain theory and neural networks,
412-415.
- Brouwer, A. M., Hogervorst, M. A., Van Erp, J. B., Heffelaar, T., Zimmerman, P. H., & Oostenveld, R.
(2012). Estimating workload using EEG spectral power and ERPs in the n-back task. Journal of neural
engineering, 9(4), 045008.
- Chen, R., Wang, X., Zhang, L., Yi, W., Ke, Y., Qi, H., & Zhou, P. (2015). Research on multi-dimensional
N-back task induced EEG variations. In Engineering in Medicine and Biology Society (EMBC), 37th
Annual International Conference of the IEEE (pp. 5163-5166). IEEE.
- Falkenstein, M., Hoormann, J., & Hohnsbein, J. (1999). ERP components in Go/Nogo tasks and their relation
to inhibition. Acta psychologica, 101(2-3), 267-291.
- Gevins, A., & Cutillo, B. (1993). Spatiotemporal dynamics of component processes in human working
memory. Electroencephalography and clinical Neurophysiology, 87(3), 128-143.
- Gevins, A., Smith, M. E., McEvoy, L., & Yu, D. (1997). High-resolution EEG mapping of cortical activation
related to working memory: effects of task difficulty, type of processing, and practice. Cerebral cortex,
7(4), 374-385.
- Ila, A. B., & Polich, J. (1999). P300 and response time from a manual Stroop task. Clinical Neurophysiology, 110(2),
367-373.
- Jensen, O., & Tesche, C. D. (2002). Frontal theta activity in humans increases with memory load in a working
memory task. European journal of Neuroscience, 15(8), 1395-1399.
- Johnson Jr, R.. (1993) On the neural generators of the P300 component of the event‐related
potential. Psychophysiology, 30(1), 90-97.
- Key, A. P. F., Dove, G. O., & Maguire, M. J. (2005). Linking brainwaves to the brain: an ERP primer. Developmental
neuropsychology, 27(2), 183-215.
- Klimesch, W. (1999). EEG alpha and theta oscillations reflect cognitive and memory performance: a review and
analysis. Brain research reviews, 29(2-3), 169-195.
- Kopp, B., Rist, F., & Mattler, U. W. E. (1996). N200 in the flanker task as a neurobehavioral tool for investigating
executive control. Psychophysiology, 33(3), 282-294.
- Krause, C. M., Sillanmäki, L., Koivisto, M., Saarela, C., Häggqvist, A., Laine, M., & Hämäläinen, H. (2000).
The effects of memory load on event-related EEG desynchronization and synchronization. Clinical
neurophysiology, 111(11), 2071-2078.
- Luck, S. J., & Kappenman, E. S. (2011). The Oxford handbook of event-related potential components. Oxford
university press.
Missonnier, P., Deiber, M. P., Gold, G., Millet, P., Pun, M. G. F., Fazio-Costa, L., & Ibáñez, V. (2006). Frontal
theta event-related synchronization: comparison of directed attention and working memory load
effects. Journal of Neural Transmission, 113(10), 1477-1486.
Nunez, P. L., & Srinivasan, R. (2006). Electric fields of the brain: the neurophysics of EEG. USA: Oxford University
Press.
Pesonen, M., Hämäläinen, H., & Krause, C. M. (2007). Brain oscillatory 4–30 Hz responses during a visual
n-back memory task with varying memory load. Brain research, 1138, 171-177.
- Raichle, M. E., MacLeod, A. M., Snyder, A. Z., Powers, W. J., Gusnard, D. A., & Shulman, G. L. (2001). A
default mode of brain function. Proceedings of the National Academy of Sciences, 98(2), 676-682.
- Ray, W. J., & Cole, H. W. (1985). EEG activity during cognitive processing: influence of attentional
factors. International Journal of Psychophysiology, 3(1), 43-48.
- Tsoneva, T., Baldo, D., Lema, V., & Garcia-Molina, G. (2011). EEG-rhythm dynamics during a 2-back working
memory task and performance. In Engineering in Medicine and Biology Society, EMBC, 2011 Annual
International Conference of the IEEE (pp. 3828-3831). IEEE.
- Vogel, E. K., & Luck, S. J. (2000). The visual N1 component as an index of a discrimination
process. Psychophysiology, 37(2), 190-203.
- Watter, S., Geffen, G. M., & Geffen, L. B. (2001). The n-back as a dual-task: P300 morphology under divided
attention. Psychophysiology, 38(6), 998-1003.
- Wetzel, W., Ott, T., & Matthies, H. (1977). Post-training hippocampal rhythmic slow activity (“theta”) elicited
by septal stimulation improves memory consolidation in rats. Behavioral biology, 21(1), 32-40.
- Zunini, R. A. L., Knoefel, F., Lord, C., Dzuali, F., Breau, M., Sweet, L., & Taler, V. (2016). Event-related
potentials elicited during working memory are altered in mild cognitive impairment. International
Journal of Psychophysiology, 109, 1-8.