PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 9197516

Relative alpha desynchronization and synchronization during speech perception.

C M Krause·B Pörn·A H Lang·M Laine
View original source ↗Export metadata ↓

Abstract

Brain processes elicited by speech were studied in 10 right-handed subjects by means of examining the desynchronization and synchronization of the 8-10 Hz and 10-12 Hz EEG alpha frequency bands. The subjects listened to an auditorily presented 5 min text passage. The text was presented both forward and backward. Listening to the text forward elicited alpha desynchronization in both of the frequency bands studied, whereas listening to the same text presented backward elicited synchronization in the 10-12 Hz frequency band only. Listening to the text forward elicited greater desynchronization than listening to the text backward. In the 10-12 Hz frequency band, listening to the text forward elicited desynchronization whereas listening to the same text backward elicited synchronization. This dissociation was not observed in the 8-10 Hz frequency band. The results suggest that the lower and upper alpha bands differ such that the 10-12 Hz frequency band exhibits reactivity to the presence of linguistic content while the 8-10 Hz band shows an unspecific response.

Explore related subjects

Acoustic StimulationAdultAlpha RhythmFemaleHumansMaleSpeech PerceptionTime FactorsJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

C M Krause, B Pörn, A H Lang, M Laine. 1997. Relative alpha desynchronization and synchronization during speech perception.. https://doi.org/10.1016/s0926-6410(97)00009-8

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1999

Cortical processing of complex tone stimuli: mismatch negativity at the end of a period of rapid pitch modulation.

In this study, synthesised instrumental tones were used to examine human auditory cortical processes engaged at the end of a period of rapid pitch modulation. It was previously [S.J. Jones, O. Longe, M. Vaz Pato, Auditory evoked potentials to abrupt pitch and timbre change of complex tones: electrophysiological evidence of 'streaming'?, Electroencephalogr. Clin. Neurophysiol., 108 (1998) 131-142] suggested that the 'change-N1' produced by infrequent changes in pitch or timbre of a continuous complex tone represents the activity of a neuronal population topographically distinct from that responsible for the 'onset-N1' at the beginning of the tone. In the present study a superficially similar negativity was produced when the tone came to rest on a steady pitch after a period of rapid (8-16 changes/s) modulation; its scalp maximum was anterior to that of the two previously identified potentials but similar to that of the mismatch negativity elicited by discontinuous tones. By varying the modulation rate the latency was shown to be relatively constant with respect to the time the next pitch change was expected but failed to occur. The largest responses averaging c. 7 microV were evoked at the end of modulation sequences which were both rhythmic and repetitive, but a potential was still produced when there was no rhythmic pattern or repetition of individual notes. This response to non-occurrence of an expected but not necessarily specified change implies an automatic process for comparing the incoming sound with an extrapolated template of the preceding pattern in which timing as well as pitch information is accurately represented. We suggest this technique offers a robust method for eliciting the mismatch negativity, which may extend the opportunities for electrophysiological investigation of higher auditory processes.

Acoustic Stimulation↗
PubMed1999

Effects of age on working memory: an event-related potential study.

The effects of age on behavioural performance and event-related potentials recorded during a working memory task using digits presented either acoustically or visually, were studied in 37 healthy subjects with an age range from 19 to 71 years. With increasing age, psychological tests showed a progressive decline in visuo-spatial performance and both auditory and visual reaction times (RT) increased. There were multiple and varying effects of age on both early and late ERP components. For both auditory and visual responses, increasing age was associated with an increased amplitude of early positive waves (auditory P100 and visual P145) and, in the oldest subjects, significant delays of the major late positive waves. Other changes were modality-specific with a progressive shift of amplitude maxima in the early negative waves of the visual ERPs (from an N190 peak maximal at Pz in the young, to an N270 peak maximal at Cz in the older subjects) and an altered amplitude distribution of late potentials (after the P250 wave) in the auditory responses. The age at which ERP changes occurred varied-significant latency prolongations and increases in the amplitude of the major frontal positive waves occurred only in the oldest subjects, whereas a redistribution of late auditory ERPs also occurred in the intermediate age group. There was no interaction between age and increasing memory load, suggesting that there is no specific effect of age on memory scanning in this age range for these levels of task difficulty. Thus, although performance in working memory was apparently unaffected by age, as judged by behavioural parameters (apart from slowing of the reaction times), ERPs revealed significant changes in both early and late electrical brain processes associated with working memory as age increases. These changes which were not symptomatically manifest and only revealed by sensitive tests, may represent subtle dysfunction of working memory (or associated processes) which does not prevent the successful completion of our task, compensatory mechanisms (which are essential to successfully complete the task), or a combination of both age-induced dysfunction and compensatory mechanisms.

Acoustic Stimulation↗
PubMed1999

Selective tuning of the left and right auditory cortices during spatially directed attention.

Effects of spatially directed auditory attention on human brain activity, as indicated by changes in regional cerebral blood flow (rCBF), were measured with positron emission tomography (PET). Subjects attended to left-ear tones, right-ear tones, or foveal visual stimuli presented at rapid rates in three concurrent stimulus sequences. It was found that attending selectively to the right-ear input activated the auditory cortex predominantly in the left hemisphere and vice versa. This selective tuning of the left and right auditory cortices according to the direction of attention was presumably controlled by executive attention mechanisms of the frontal cortex, where enhanced activation during auditory attention was also observed.

Acoustic Stimulation↗