Event-related EEG/MEG synchronization and desynchronization: basic principles.

http://download.neurosky.com/docs/papers/bcq/Klimesch_1999_EEG_alpha_and_theta_oscillations_reflect_cognitive_and_memory_performance.pdf

EEG alpha and theta oscillations reflect cognitive and memory performance: a review and analysis

The mismatch negativity (MMN) in basic research of central auditory processing: a review.

Oscillatory gamma activity in humans and its role in object representation

In the present article, the basic research using the mismatch negativity (MMN) and analogous results obtained by using the magnetoencephalography (MEG) and other brain-imaging technologies is reviewed. This response is elicited by any discriminable change in auditory stimulation but recent studies extended the notion of the MMN even to higher-order cognitive processes such as those involving grammar and semantic meaning. Moreover, MMN data also show the presence of automatic intelligent processes such as stimulus anticipation at the level of auditory cortex. In addition, the MMN enables one to establish the brain processes underlying the initiation of attention switch to, conscious perception of, sound change in an unattended stimulus stream. 2007 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

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Invited review The mismatch negativity (MMN) in basic research of central auditory processing: A review

Testretest consistency of the ERD/ERS of the 46, 68, 810 and 1012 Hz frequency bands during a memory task

The critical nature of between- and within-subjects variation in event-related brain oscillatory EEG responses

Aivoja ja niiden toimintaa voidaan nykyaan tutkia monin erilaisin menetelmin. EEG (electroencephalogram) ja MEG (magnetoencephalogram) antavat aivojen toiminnasta ajallisesti tarkkaa (mutta vain kohtalaisella paikkatarkkuudella) informaatiota kun taas PET (positroniemissiotomografi a) ja fMRI (toiminnallinen magneettikuvantaminen) kertovat hyvalla paikkatarkkuudella missa kohden aivoja jokin prosessi toteutuu (mutta vain kohtuullisella aikatarkkuudella). Myos aivovauriopotilailta seka erilaisista keskushermoston sairauksista karsivilta henkiloilta saatu aineisto valottaa omalla tavallaan myos vaurioitumattomien aivojen toimintaa. 1990-lukua kutsuttiin ”aivojen vuosikymmeneksi” ja alkanutta 2000-lukua voitaneen kutsua ”aivokuvantamisen vuosikymmeneksi” menetelmallisen kehityksen vuoksi. Kahtena viime vuosikymmenena tutkimus on valottanut aivojen toimintaa enemman kuin koskaan aikaisemmin. Asian kaantopuolena voidaan todeta, etta olemme tiedostaneet, etta aivojen toiminta on niin monimutkaista, etta tiedamme ettemme viela tieda, miten aivot toimivat.

Aivojen sähköinen taustatoiminta ja kognitiiviset prosessit

Brain Oscillations and Cognitive Processes Christina M. Krause (christina.krause@helsinki.fi) Cognitive Science, Department of Psychology, Faculty of Behavioral Sciences, University of Helsinki, POB 9, 00014 Helsinki, Finland. Introduction The relevance for Cognitive Science Cognitive neuroscience now leaves little or no doubt that cognitive processes require the transient integration of numerous, widely distributed, constantly interacting areas of the brain. The most plausible mechanism for such a large- scale integration is the formation of dynamic links mediated by synchrony over multiple frequency bands. Neurons can exhibit a wide range of oscillations (~4-70 Hz) which can enter into precise synchrony over a limited period of time (millisecond scale). Brain oscillatory systems have been proposed to act as possible communication networks with functional relations to memory and cognition. This paper presents recent findings on macroscopic brain electric oscillations as an index of cognitive processing. Time and temporal integration of information are undoubtedly among the most important properties of human cognition. Theoretically, brain electric oscillations may serve as carrier signals for cognitive processes (e.g., “online” speech perception), appropriate to establish rapid coupling of spatially separate cell assemblies. The study of neuronal oscillations is concerned with the mutual coordination and communication between neurons in different parts of the brain. This kind of systems-level research is particularly exciting because of its potential to shed light on the transmission of information in the kinds of widely distributed neuronal networks relevant for higher cognitive processing. This integrative research may be of importance when bridging the gap between the neurophysiological and the cognitive approaches to understanding complex brain function. Brain Oscillations Macroscopic EEG signals arising from the brain consist of several simultaneous oscillations, which can be subdivided into frequency bands such as delta (1-3 Hz), theta (4-8 Hz), alpha (8-12 Hz), beta (about 14-30 Hz) and gamma (around 40 Hz). Different neural generators are involved in the generation of brain oscillations at different frequencies. Hippocampal neural activity seems to be reflected as oscillations within the theta frequency range while the alpha rhythms seem to be mainly generated by cortico-cortical and thalamocortical neural networks. The beta rhythm is generated mainly in the motor cortices. Gamma brain oscillations have been observed in association with visual, auditory and motor tasks and might exist in a number of brain structures with somewhat different functional/behavioral correlates. Acknowledgments Professor Christina M. Krause has been funded by the Academy of Finland and by the University of Helsinki (own research funds and travel grant) which is gratefully acknowledged. References Brain Oscillations and Cognitive processes Working memory processes seem to be reflected as oscillations within the EEG theta frequencies. Alpha frequency responses can be observed in association with tasks requiring alertness, attention and semantic memory processes. Auditory memory encoding and retrieval typically elicit distinct brain oscillatory responses: encoding elicits ~10 Hz synchronization whereas retrieval evokes ~10 Hz desynchronization (Krause et al., 1996). Memory search experimental paradigms have recently been utilized in clinical settings (Karrasch et al., in press; Ellfolk et al., under preparation). Brain oscillatory responses can be utilized to assess the neural correlates of language processing (Nikitenkova, Laine & Krause, under preparation; Herkman et al., under preparation). Beta rhythm responses have been reported in association with cognitive processing (Karrasch et al., 2004). Ellfolk, U, Karrasch, M, Laine, M, Pesonen, M, & Krause, CM. (under preparation). Event-related desynchronization /synchronization during a memory task in early Parkinson’s disease. Herkman, J, Pesonen, M, Service, E, & Krause, CM. (under preparation). Brain oscillatory responses during metaphor processing. Karrasch, M., Laine, M., Rapinoja, P., & Krause, CM. (2004). Effects of normal aging on event-related desynchronization/synchronization during a memory task in humans. Neuroscience Letters, 366, 18-23. Karrasch, M, Laine, M, Rinne, JO, Rapinoja, P, & Krause, CM. (in press). Brain oscillatory responses to an auditory memory task in Mild Cognitive Impairment and Alzheimer’s disease. International Journal of Psychophysiology. Nikitenkova, A, Laine, M, & Krause, CM. (under preparation). Electrophysiological correlates of memory processing in Finnish-Swedish early bilinguals Krause, CM, Lang, AH, Laine, M, Kuusisto, M, & Porn, B. (1996). Event-related EEG desynchronization and synchronization during an auditory memory task. Electroencephalography and Clinical Neurophysiology,

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Christina M. Krause

Papers

Testretest consistency of the ERD/ERS of the 46, 68, 810 and 1012 Hz frequency bands during a memory task

The critical nature of between- and within-subjects variation in event-related brain oscillatory EEG responses

Aivojen sähköinen taustatoiminta ja kognitiiviset prosessit

Brain Oscillations and Cognitive Processes - eScholarship

Psykologian historiaa amerikkalaisesta näkökulmasta