Biomedical subjects

M Tervaniemi

Publications and source records attributed to M Tervaniemi.

At least 19 recordsLinked to original sources

PubMed1999

Superior pre-attentive auditory processing in musicians.

The present study focuses on influences of long-term experience on auditory processing, providing the first evidence for pre-attentively superior auditory processing in musicians. This was revealed by the brain's automatic change-detection response, which is reflected electrically as the mismatch negativity (MMN) and generated by the operation of sensoric (echoic) memory, the earliest cognitive memory system. Major chords and single tones were presented to both professional violinists and non-musicians under ignore and attend conditions. Slightly impure chords, presented among perfect major chords elicited a distinct MMN in professional musicians, but not in non-musicians. This demonstrates that compared to non-musicians, musicians are superior in pre-attentively extracting more information out of musically relevant stimuli. Since effects of long-term experience on pre-attentive auditory processing have so far been reported for language-specific phonemes only, results indicate that sensory memory mechanisms can be modulated by training on a more general level.

Acoustic Stimulation↗

PubMed1999

Functional specialization of the human auditory cortex in processing phonetic and musical sounds: A magnetoencephalographic (MEG) study.

Functional specialization of the human auditory cortex in processing phonetic vs musical sounds was investigated. While subjects watched a silent self-selected movie, they were presented with sequences consisting of frequent and infrequent phonemes (/e/ and /o/, respectively) or chords (A major and A minor, respectively). The subjects' brain responses to these sounds were recorded with a 122-channel whole-head magnetometer. The data indicated that within the right hemisphere, the magnetoencephalographic (MEG) counterpart MMNm of the mismatch negativity (MMN) elicited by an infrequent chord change was stronger than the MMNm elicited by a phoneme change. Within the left hemisphere, the MMNm strength for a chord vs phoneme change did not significantly differ. Furthermore, the MMNm sources for the phoneme and chord changes were posterior to the P1m sources generated at or near the primary auditory areas. In addition, the MMNm source for a phoneme change was superior to that for the chord change in both hemispheres. The data thus provide evidence for spatially distinct cortical areas in both hemispheres specialized in representing phonetic and musical sounds.

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↗

PubMed1998

Background acoustic noise and the hemispheric lateralization of speech processing in the human brain: magnetic mismatch negativity study.

The present study explored effects of background noise on the cerebral functional asymmetry of speech perception. The magnetic equivalent (MMNm) of mismatch negativity (MMN) elicited by consonant-vowel syllable change presented in silence and during background white noise was measured with a whole-head magnetometer. It was found that in silence MMNm to speech stimuli, registered from the auditory cortex, was stronger in the left than in the right hemisphere. However, when speech signals were presented in white noise background, MMNm in the left hemisphere diminished while that in the right hemisphere increased in amplitude and dipole moment. These results confirm that in silence, speech signals are mainly discriminated in the left hemisphere's auditory cortex. However, in noisy conditions the involvement of the left hemisphere's auditory cortex in speech discrimination is considerably decreased, while that of the right hemisphere increases.

Brain↗

PubMed1998

Preattentive processing of auditory spatial information in humans.

Auditory event-related potentials were recorded from reading subjects to frequent and infrequent tones. Frequent tones presented by a loudspeaker in front of the subject were interspersed with infrequent tones delivered either by one of the symmetrically-placed lateral loudspeakers, or by both lateral loudspeakers simultaneously. This latter sound was perceived as originating from a spacious source in the direction of the central loudspeaker. A sizable mismatch negativity (MMN) and P3a were elicited by all three infrequent stimuli, suggesting that infrequent changes in the direction or perceived spaciousness of the sound source were preattentively detected. In addition, a dissociation between the MMN and P3a amplitudes was found: whereas lateral deviants elicited a larger P3a than the simultaneous left + right deviant, the MMN amplitude was approximately equal for all three deviants.

Acoustic Stimulation↗

PubMed1998

The mismatch negativity for duration decrement of auditory stimuli in healthy subjects.

The amplitude and latency of the mismatch negativity (MMN) elicited by occasional shorter-duration tones (25 and 50 ms) in a sequence of 75 ms standard tones were studied in 40 healthy subjects (9-84 years). The replicability and age dependence of the MMN-responses were determined. The 25 ms deviant tone evoked a clear response in 39 of the subjects, while the 50 ms deviant tone evoked an observable MMN only in 32 of the subjects. The MMN peak amplitude for the 25 ms deviants was significantly larger than for the 50 ms deviants. There was no significant difference in the peak latencies (measured from stimulus offset). For the 25 ms deviant, the amplitude diminished with increasing age. The MMN curves for the 25 ms deviant, measured on separate days in 14 subjects, looked very replicable. As a result of noise and filtering effect, the product-moment correlations were poor. The results indicate that the signal-to-noise ratio for the MMN to 25 ms deviants, obtained even in a 25 min recording session, is large enough for clinical use and individual diagnostics when undetectable (or very low amplitude) MMN is used as a sign of pathology. However, judged from the low correlation coefficients, despite the good replicability in visual evaluation, better methods for MMN quantification have to be used for clinical follow-up.

Acoustic Stimulation↗

PubMed1998

Temporal window of integration of auditory information in the human brain.

A deviation in the acoustic environment activates an automatic change-detection system based on a memory mechanism that builds a neural trace representing the preceding sounds. The present study revealed that the auditory-cortex mechanisms underlying this sensory memory integrate acoustic events over time, producing a perception of a unitary auditory event. We recorded magnetic responses (MMNm) to occasional stimulus omissions in trains of stimuli presented at a constant stimulus-onset asynchrony (SOA) that was, in different blocks, either shorter or longer in duration than the assumed length of the temporal window of integration. A definite MMNm was elicited by stimulus omission only with the three shortest SOAs used: 100, 125, and 150 ms, but not with 175 ms. Thus, 160-170 ms was estimated as the length of the temporal window used by the central auditory system in integrating successive auditory input into auditory event percepts.

Acoustic Stimulation↗

PubMed1997

Pre-attentive categorization of sounds by timbre as revealed by event-related potentials.

Infrequent (10%) pure tones were randomly presented among nine different missing-fundamental tones having the same pitch (10% each) to subjects playing a computer game. MMN (an index of pre-attentive change detection) was elicited by timbre-deviant pure tones with 150 and 500 ms stimulus duration. This suggests that the spectral component of timbre is pre-attentively determined from relatively short (150 ms) acoustic samples. Previous research established that resolving the pitch of the same missing-fundamental tones requires longer (> 150 ms) sounds. Consequently, timbre and pitch are probably determined by separate neural processes. The present results also demonstrate pre-attentive categorization of sounds based on timbre as MMN could only be elicited by the pure tones if their timbre was contrasted with the combined group of the nine standard sounds of qualitatively similar rich timbre.

Acoustic Stimulation↗

PubMed1997

Temporal window of integration revealed by MMN to sound omission.

The central auditory system for event perception involves the integrating mechanism of sequential information addressed by the present study. The mismatch negativity (MMN) component of the event-related potentials (ERP) reflects the automatic detection of sound change. ERPs to occasionally omitted stimuli were measured when sequences with constant stimulus onset asynchronies (SOAs) were presented. In separate blocks, the SOA was from 100 to 350 ms. A clear MMN was elicited by a stimulus omission in a sequence of regularly spaced tone pips only when the SOA was shorter than 150 ms, yielding an estimate for the duration of the temporal window of integration used the perceptual segregation of auditory events.

Acoustic Stimulation↗

PubMed1997

Pre-attentive processing of spectrally complex sounds with asynchronous onsets: an event-related potential study with human subjects.

Neuronal mechanisms involved in the processing of complex sounds with asynchronous onsets were studied in reading subjects. The sound onset asynchrony (SOA) between the leading partial and the remaining complex tone was varied between 0 and 360 ms. Infrequently occurring deviant sounds (in which one out of 10 harmonics was different in pitch relative to the frequently occurring standard sound) elicited the mismatch negativity (MMN), a change-specific cortical event-related potential (ERP) component. This indicates that the pitch of standard stimuli had been pre-attentively coded by sensory-memory traces. Moreover, when the complex-tone onset fell within temporal integration window initiated by the leading-partial onset, the deviants elicited the N2b component. This indexes that involuntary attention switch towards the sound change occurred. In summary, the present results support the existence of pre-perceptual integration mechanism of 100-200 ms duration and emphasize its importance in switching attention towards the stimulus change.

Adolescent↗

PubMed1997

The first neurophysiological evidence for cognitive brain dysfunctions in children with CATCH.

CATCH syndrome, caused by a microdelection in chromosome 22, is characterized by cleft palate and cardiac anomalies. The majority of these children also have learning difficulties or speech and language deficits. These problems are often due to the dysmorphology of the articulatory system. In the present study, the duration of auditory sensory memory, which is of central importance to speech perception and understanding, was investigated. As a research method we used mismatch negativity (MMN), an attention independent event-related potential, which provides an objective electrical index of auditory sensory memory. The present data suggest that the duration of this memory span is considerably shorter in 6-10-year-old children with CATCH than in healthy controls. Thus, the language-related problems encountered in children suffering from CATCH syndrome are likely to be caused also by CNS dysfunctions.

Abnormalities, Multiple↗

PubMed1997

The musical brain: brain waves reveal the neurophysiological basis of musicality in human subjects.

To reveal neurophysiological prerequisites of musicality, auditory event-related potentials (ERPs) were recorded from musical and non-musical subjects, musicality being here defined as the ability to temporally structure auditory information. Instructed to read a book and to ignore sounds, subjects were presented with a repetitive sound pattern with occasional changes in its temporal structure. The mismatch negativity (MMN) component of ERPs, indexing the cortical preattentive detection of change in these stimulus patterns, was larger in amplitude in musical than non-musical subjects. This amplitude enhancement, indicating more accurate sensory memory function in musical subjects, suggests that even the cognitive component of musicality, traditionally regarded as depending on attention-related brain processes, in fact, is based on neural mechanisms present already at the preattentive level.

Adolescent↗

PubMed1997

Two separate codes for missing-fundamental pitch in the human auditory cortex.

Two auditory event-related potential components, the supratemporal N1 and the mismatch negativity (MMN), index traces encoding the missing-fundamental pitch. The present results suggest that these two codes derive from separate pitch extraction processes. Frequent 300-Hz and infrequent 600-Hz missing-fundamental tones were presented, in some stimulus blocks with short (150 ms), in others, with long (500 ms) stimulus durations. MMN, reflecting a preattentive change detection process, was elicited by infrequent missing-fundamental tones only in the long-duration condition. Correspondingly, subjects were able to detect these high-pitch missing-fundamental tones amongst similar low-pitch ones only when the stimulus duration was long. In addition, the MMN response peaked ca. 120 ms later for missing-fundamental tones than for pure tones of the fundamental frequency suggesting that missing-fundamental pitch resolving took substantially longer than extracting the spectral pitch. In contrast, a differential N1 response to the missing-fundamental pitch was found for both stimulus durations, with no substantial difference in peak latency between the pure and missing-fundamental tones. The contrasting features found for the two auditory cortical missing-fundamental pitch codes support the notion of two separate missing-fundamental pitch resolving mechanisms.

Adolescent↗

PubMed1996

Neural mechanisms of the octave illusion: electrophysiological evidence for central origin.

The octave illusion is experienced when two simultaneous tones, separated by one octave and presented to the opposite ears, are continuously reversed between the two ears. Subjects consistently report a sequence of alternating single tones: the high tone in the right ear and the low in the left. We wished to determine whether such a complex tone sequence is encoded as it is presented or as it is perceived. This was accomplished by making the tone sequence infrequently correspond to how it is perceived, and recording event-related potentials (ERPs) to these perceptually equivalent but physically different events. The illusion-mimicking tones elicited the mismatch negativity (MMN), a change-specific ERP component with origin in the auditory cortex. This indicates that the stimuli giving rise to the octave illusion are encoded according to their physical rather than perceptual properties. Consequently, the generator of the octave illusion is located beyond the level of the auditory cortex.

Acoustic Stimulation↗

PubMed1996

Processing of complex sounds in the human auditory cortex as revealed by magnetic brain responses.

Processing of simple and complex sounds in the human brain was compared by recording extracranial magnetic mismatch responses (MMNm; the magnetic counterpart of the mismatch negativity, or MMN) to frequency changes in these sounds. Generator sources, modeled as equivalent current dipoles (ECDs), of MMNm responses to a change in one frequency element of complex sounds (a chord and a serial tone pattern) were located in supratemporal auditory cortex, on average, 10 mm medially to the source of an MMNm elicited by an identical frequency change in a simple tone. These results suggest that at least partially different supratemporal neuron populations are involved in processing changes in simple and complex sounds and that sensory-memory representations for these sounds may be located in different fields of the auditory cortex.

Adult↗

PubMed1996

Preattentive periodicity detection in auditory patterns as governed by time and intensity information.

The present study demonstrated that the mismatch negativity (MMN), generated by the brain's preattentive detection of a sound change, is elicited by infrequent reversals of two consecutive tones differing in intensity. When tones were presented in a pairwise manner, the MMN was time-locked to the onset of the intensity reversal. When the tones were continuously presented, the MMN was elicited by an irregular loud tone succeeding a regular loud tone but not by an irregular soft tone following a regular soft tone. Results suggest that the preattentive construction of auditory units is primarily governed by the timing of tone presentation but that it may also utilize intensity information, when no sufficient timing information is available.

Acoustic Stimulation↗

PubMed1995

Time course of loudness in tone patterns is automatically represented by the human brain.

The present study investigated the neural mechanisms of intensity coding by presenting human subjects repetitively with tone pairs consisting of two tones differing in intensity. The first tone was higher in sound pressure level than the second (70 versus 58 dB SPL). Infrequent order reversals of the two tones elicited the mismatch negativity (MMN), an event-related brain potential probe of preattentive auditory sensory memory. This finding indicates that the human auditory system automatically encodes information about the time course of intensity within tone patterns into neural representations.

Adult↗

PubMed1995

From objective to subjective: pitch representation in the human auditory cortex.

Magnetic brain responses to infrequent changes in the pitch of complex sounds were recorded. The composition of the test sounds required that pitch-deviant stimuli elicited the mismatch response only if perceived pitch was represented in auditory sensory memory. Results revealed that subjective features, such as pitch, are formed from objective stimulus parameters (i.e. the spectral contents of a sound) before storing acoustic information in memory. The origin of the magnetic response to pitch change showed that pitch deviation was detected in the auditory cortex. Pitch memory might also be located in the auditory cortex, as previous evidence suggests that storage for an auditory feature lies in the vicinity of the neuronal elements activated by deviations in that feature.

Acoustic Stimulation↗