Document Type : Full Research Paper

Authors

1 Instructor, Department of Biomedical Engineering, Islamic Azad University of Mashhad Branch

2 Assistant Professor, Department of Biomedical Engineering, Islamic Azad University of Mashhad Branch,

3 Associate Professor, Department of Biology, Sciences School, Ferdowsi University

10.22041/ijbme.2008.13545

Abstract

Episodic memory is the explicit recollection of incidents occurred at a particular time and place in One’s Personal Past. In This Study, Detection of Episodic Memory Activity In Event Related Potentials (ERPs) was done. ERPs were recorded while the subjects made old/new recognition judgments on the new unstudied meaningless pictures and the old pictures which had been presented at the study phase. In order to extract the features correlated with the episodic memory activity, time and time-frequency features were extracted from ERPs. Wavelet method was implemented for feature extraction in time-­frequency. Independent sample test has was for detection of the separable degree the between old/new ERPs. Furthermore, by using stepwise linear discriminate analysis, ERP signals were classified to old and new classes. Ultimately for better classification between old/new ERPs, Multilayer Perceptron was implemented, and for best feature selection, genetic algorithm was used. In the best results, by using time domain features extracted from Pz channel, 100% accuracy in the training and test data was obtained. 

Keywords

[1]     Squire L.R., Knowlton B.J., Memory, hippocampus and brain systems; Cognitive Neuroscience, MIT Press, Cambridge, MA; 1994:825-837.
[2]     Johnson R.Jr., Event-related potential insights into the neurobiology of memory systems; the handbook of neuropsychology, Vol. 10. Amsterdam: Elsevier Science Publishers; 1995a:135–164.
[3]     Rugg M.D., ERP studies of memory; Electrophysiology of mind: event-related brain potentials and cognition, New York: Oxford University Press; 1995;15:132–170.
[4]     Friedman D., ERPs during continuous recognition memory for words; Biol Psychol; 1990; 30:61–87.
[5]     Besson M., Kutas M., Van Petten C., An event related potential (ERP) analysis of semantic congruity and repetition effects in sentences; J Cog Neurosci;1992; 4:132–149.
[6]     Finnigan S., Humphreys M.S., Dennis S,Geffen G., ERP ‘old/new’ effects: memory strength and decisional factor(s); Neuropsychologia; 2002; 40:2288-2304.
[7]     Dzulkifli M.A., Herron J.E., Wilding E.L., Memory retrieval processing: Neural indices of processes supporting episodic retrieval; Neuropsychologia;2006; 44:1120-1130.
[8]     Milner B., Corsi P., Leonard G., ;Frontal lobe contribution to recently judgments; Neuropsychologia; 1991; 29:601-618.
[9]     Moscovitch M., Confabulation In Memory Distortion: How minds, Brains and Societies Reconstruct the past; Harvard University Press, Cambridge, MA; 1995:226- 254.
[10] Buckner R.L., Tulving E., Neuroimaging studies of memory: Theory and recent PET results; Handbook of Neuropsychology, Elsevier, Amsterdam; 1995:439- 466.
[11] Ungerleider L.G., Functional brain imaging studies of cortical mechanisms for memory; Science; 1995; 270:760-775.
[12] Martin A., Wiggs C.L., Weisberg J.A., Modulation of human temporal lobe activity by form, meaning, and experience; Hippocampus; 1997; 7:587-593.
[13] Schacter D.L., Alpert N.M., Savage C..R, Rauch S. L., Albert M.S., Conscious recollection and the human hippocampal formation: Evidence from position emission tomography; Proc. Natl. Acad. Sci. U.S.A; 1996; 93:321-325.
[14] Blanchet S., Belleville S., Lavoie M.E., Item-related versus task-related activity during encoding and retrieval in verbal and non-verbal episodic memory: an event-related potential study; Cognitive Brain Research; 2003; 17:462–474.
[15] ابوطالبی وحد، مرادی محمدحسن، خلیل‌زاده محمدعلی؛ آشکارسازی مولفه‌های شناختی سیگنال مغز با استفاده از ضرایب ویولت؛ مجله مهندسی پزشکی زیستی، پاییز 1383، اول (اول): 25-46.
[16] عبدالصالحی مهدی، قشونی مجید، خلیل‌زاده محمدعلی؛ فیلترسازی غیرخطی EOG از سیگنال EEG با استفاده از ANFIS؛ ششمین کنفرانس سیستم‌های فازی ایران و نخستین کنفرانس سیستم‌های فازی در جهان اسلام؛ اردیبهشت 85، 117-123.
[17] قشونی مجید، خلیل‌زاده محمدعلی؛ بهبود تشخیص مولفه‌های شناختی در سیگنال ERP تک‌ثبت با استفاده از فضای ویژگی جدید و الگوریتم ژنتیک؛ دوازدهمین کنفرانس مهندسی پزشکی ایران؛ آبان 1384، 188-194.
[18] Miller M.T., Jerebko A.K., Malley J.D., Summers R.M.; Feature Selection for Computer-Aided Polyp Detection using Genetic Algorithms; Proceedings of SPIE; 2003; 5031:102-110.
[19] Donaldson D.I., Rugg M.D., Recognition memory for new associations: Electrophysiological evidence for the role of recollection; Neuropsychologia; 1998; 36: 377-395.
[20] Wilding E.L., Rugg M.D., An event related potential study of recognition memory with and without retrieval of source; Brain; 1996; 119:889-905.
[21] Allan K., Wilding E.L., Rugg M.D., Electrophysiological evidence for dissociable processes contributing to recollection; Acta psychological; 1998; 98:231-252.
[22] Johnson R., Jr Kreiter K., Russo B., Zhu J., A spatiotemporal analysis of recognition-related event-related brain potentials; Int J Psychophysiol; 1998a; 29:83– 104.
[23] Allan K., Rugg M.D., An event-related potential study of explicit memory on tests of cued recall and recognition; Neuropsychologia; 1997; 35:387–397.
[24] Howard M.W., et al; Gamma oscillations correlate with working memory load in humans; Cerebral cortex; 2003; 13:1369 1374.