Biomedical subjects

Minna Huotilainen

Publications and source records attributed to Minna Huotilainen.

12 recordsLinked to original sources

PubMed2003

The newborn human brain binds sound features together.

To process a stimulus as a holistic entity, the human brain must be able to conjoin its different features. Previous evidence suggests that this ability emerges during the first months of life, implying its considerable dependence on postnatal development. We recorded human newborn (1-3 days of age) electrical brain responses to frequently occurring (standard) sounds and to rarely occurring (deviant) sounds in a series. Responses to deviants differed from those to standards despite the fact that only the combination of sound frequency and intensity could be used as a cue for discriminating between these sound types. Our finding suggests that the human brain is ready for auditory feature binding very soon after birth.

Acoustic Stimulation↗

PubMed2003

Auditory magnetic responses of healthy newborns.

We recorded magnetic brain activity from healthy human newborns when they heard frequency changes in an otherwise repetitive sound stream. We were able to record the magnetic counterpart of the mismatch negativity (MMN) previously described only with electric recordings in infants. The results show that these recordings are possible, although still challenging due to the small head size and head movements. The modelling of the neural sources underlying the recorded responses suggests cortical sources in the temporal lobes.

Acoustic Stimulation↗

PubMed2003

Newborn infants can organize the auditory world.

The perceptual world of neonates is usually regarded as not yet being fully organized in terms of objects in the same way as it is for adults. Using a recently developed method based on electric brain responses, we found that, similarly to adults, newborn infants segregate concurrent streams of sound, allowing them to organize the auditory input according to the existing sound source. The segregation of concurrent sound streams is a crucial step in the path leading to the identification of objects in the environment. Its presence in newborn infants shows that the basic abilities required for the development of conceptual objects are available already at the time of birth.

Adult↗

PubMed2003

Plastic cortical changes induced by learning to communicate with non-speech sounds.

With Morse code, an acoustic message is transmitted using combinations of tone patterns rather than the spectrally and temporally complex speech sounds that constitute the spoken language. Using MEG recordings of the mismatch negativity (MMN, an index of permanent auditory cortical representations of native language speech sounds), we probed the dominant hemisphere for the developing Morse code representations in adult Morse code learners. Initially, the MMN to the Morse coded syllables was, on average, stronger in the hemisphere opposite to the one dominant for the MMN to native language speech sounds. After a training period of 3 months, the pattern reversed, however: the mean Morse code MMN became lateralized to the hemisphere that was predominant for the speech-sound MMN. This suggests that memory traces for the Morse coded acoustic language units develop within the hemisphere that already accommodates the permanent traces for natural speech sounds. These plastic changes manifest, presumably, the close associations formed between the neural representations of the tone patterns and phonemes.

Acoustic Stimulation↗

PubMed2003

Linguistic relevance of duration within the native language determines the accuracy of speech-sound duration processing.

As indexed by electrophysiological measures, in native speakers of a language with linguistically significant opposition between short and long phonemes, the pre-attentive detection accuracy of duration changes in speech sounds was tuned in comparison with that in non-speech sounds. This was not observed in advanced second-language users of the same language, suggesting that second-language acquisition does not lead to speech-specific tuning of the duration processing as does native language acquisition in early childhood.

Adolescent↗

PubMed2003

Event-related potentials associated with second language learning in children.

OBJECTIVE: In this study, we investigated learning-related changes in auditory event-related potentials (ERPs) of Finnish-speaking 3-6-year-old children caused by learning French language. METHODS: Using an oddball paradigm, ERPs to sounds of French language were recorded in the two groups of healthy children: those who were learning French (experimental group) and those who were not learning any foreign language (control peers). RESULTS: When the children from the experimental group were exposed to the foreign language, they automatically developed French-specific memory traces that helped them to discriminate, categorize, and pronounce utterances of the new language as indicated by the mismatch negativity (MMN) component of the ERPs in a previous study. We found that the learning process was also reflected by changes in P3a and late difference negativity (LDN) responses. Unlike MMN and P3a, the LDN has been discovered relatively recently and its functional role remains unclear. Similarly, as the MMN magnitude increased during the learning process, an increase of the P3a (known to reflect the involuntary attention switching toward deviant stimuli) and LDN amplitudes was observed. The ERPs of the control peers did not change significantly over the test period. CONCLUSIONS: When phonemes of a foreign language are learned, this process is accompanied with the increase in the MMN, P3a, and LDN amplitudes in children. Though the functional significance of LDN remains to be further investigated, our results support its possible link to reorienting processes following distraction.

Acoustic Stimulation↗

PubMed2003

Recommended standards for fetal magnetocardiography.

Fetal magnetocardiography (FMCG) is increasingly being used in research and diagnostics of fetal heart function. Currently, FMCG is the only noninvasive procedure available, comparable to postnatal ECG, which can be used to assess cardiac electrophysiology during the second and third trimester of pregnancy. For a reliable evaluation and full clinical acceptance of this new technique, large numbers of patient investigations are required which can only be obtained in multicenter studies. An international standard protocol is needed to allow pooling of sufficient data and to permit the comparison of studies performed in different centers. This article provides recommended standards for FMCG in the fields of data acquisition and data analysis.

Arrhythmias, Cardiac↗

PubMed2003

The promises of change-related brain potentials in cognitive neuroscience of music.

Even when simultaneously performing a task unrelated to sounds, the human auditory cortex can precisely model the invariances of the acoustic environment. Data acquired in a mismatch negativity (MMN) paradigm have shown that temporally and spectrally complex sounds as well as their relations are automatically represented in the human auditory cortex. Furthermore, MMN data indicate that these neural sound representations are spatially distinct from phonetic and musical sounds within and between the cerebral hemispheres. Most MMN studies were conducted in pitch dimension, but temporal aspects of sound processing are also under increasing experimentation. To some extent, musical expertise is also reflected in sound representation accuracy as indexed by the MMN paradigm.

Auditory Cortex↗

PubMed2002

Abstract phoneme representations in the left temporal cortex: magnetic mismatch negativity study.

We investigated the brain mechanisms enabling one automatically discriminate phoneme category irrespective of the large inter-speaker variability in the acoustic features of the voices. For this purpose, subjects were presented with 450 different speech stimuli, each uttered by a different speaker, belonging to three vowel categories, while a 306-channel magnetoencephalogram (MEG) was obtained to record the magnetic counterpart of the mismatch negativity (MMNm), elicited only when sensory memory traces for repetitive sounds are formed in the auditory cortex. Despite this wide acoustic variation, category changes elicited prominent MMNm responses, which were considerably stronger in the left than in the right hemisphere in the right-handed subjects. These results implicate the presence of long-term memory traces for vowels, which can recognize the vowel-specific invariant code enabling correct vowel percept even in the presence of realistic acoustic variation.

Adult↗

PubMed2002

Top-down effects can modify the initially stimulus-driven auditory organization.

We recorded event-related potentials (ERPs) and magnetic fields (ERFs) of the human brain to determine whether top-down control could modulate the initial organization of sound representations in the auditory cortex. We presented identical sound stimulation and manipulated top-down processes by instructing participants to either ignore the sounds (Ignore condition), to detect pitch changes (Attend-pitch condition), or to detect violations of a repeating tone pattern (Attend-pattern condition). The ERP results obtained in the Attend-pattern condition dramatically differed from those obtained with the other two task instructions. The magnetoencephalogram (MEG) findings were fully compatible, showing that the neural populations involved in detecting pattern violations differed from those involved in detecting pitch changes. The results demonstrate a top-down effect on the sound representation maintained in auditory cortex.

Acoustic Stimulation↗

PubMed2002

Impaired temporal lobe processing of preattentive auditory discrimination in schizophrenia.

Feature-specific stimulus discrimination related to short-term auditory sensory memory can be studied electrophysiologically using a specific event-related potential (ERP) component termed mismatch negativity (MMN), which is generated in the auditory cortex, indexing automatic comparison of the existing memory trace to incoming novel stimuli. Previous results with electroencephalography (EEG) and magnetoencephalography (MEG) suggest that schizophrenia patients have attenuated MMN response and that preattentive auditory processing preceding MMN appears to be functionally asymmetric in schizophrenia. Here we studied parallel MMN activity of the hemispheres using a whole-head MEG by presenting stimulus blocks consisting of frequent standard and infrequent deviant tones to 15 schizophrenia patients and 19 healthy control subjects. Auditory evoked fields (AEFs) were recorded simultaneously over both auditory cortices. The equivalent current dipole (ECD) modeling revealed that patients had significant MMNm reduction (magnetic counterpart of MMN) in both temporal lobes. In addition, patients had significantly delayed MMNm in the left but not in the right hemisphere to ipsilateral auditory stimuli. These results suggest that patients with schizophrenia have impaired auditory processing in the temporal lobes underlying preattentive stimulus discrimination that is also selectively delayed in the left hemisphere.

Adult↗

PubMed2002

Auditory ERPs reveal brain dysfunction in infants with plagiocephaly.

It is suspected that the developmental delay in school-aged children diagnosed as infants suffering from plagiocephaly is caused by the modification of the skull form. To detect possible cognitive impairment in these children, we examined auditory ERPs to tones in infant patients. The infants with plagiocephaly exhibited smaller amplitudes of the P150 and the N250 responses to tones than healthy controls. Differences between the patients and control subjects indicate that already at this early age the presence of the plagiocephalic skull signals compromise of brain functioning. The present data suggest that most of the plagiocephalic infants have an elevated risk of auditory processing disorders. In the current study we demonstrated, for the first time, that the central sound processing, as reflected by ERPs, is affected in children with plagiocephaly.

Analysis of Variance↗