Biomedical subjects

Satu Pakarinen

Publications and source records attributed to Satu Pakarinen.

5 recordsLinked to original sources

PubMed2006

Heschl's gyrus, posterior superior temporal gyrus, and mid-ventrolateral prefrontal cortex have different roles in the detection of acoustic changes.

A part of the auditory system automatically detects changes in the acoustic environment. This preattentional process has been studied extensively, yet its cerebral origins have not been determined with sufficient accuracy to allow comparison to established anatomical and functional parcellations. Here we used event-related functional MRI and EEG in a parametric experimental design to determine the cortical areas in individual brains that participate in the detection of acoustic changes. Our results suggest that automatic change processing consists of at least three stages: initial detection in the primary auditory cortex, detailed analysis in the posterior superior temporal gyrus and planum temporale, and judgment of sufficient novelty for the allocation of attentional resources in the mid-ventrolateral prefrontal cortex.

Acoustic Stimulation↗

PubMed2006

Measurement of extensive auditory discrimination profiles using the mismatch negativity (MMN) of the auditory event-related potential (ERP).

OBJECTIVE: Mismatch negativity (MMN), a change-specific component of the auditory event-related potential (ERP), is sensitive to deficits in central auditory processing associated with many clinical conditions. The aim of this study was to obtain a comprehensive multi-dimensional profile of central auditory processing by extending the recently developed fast multi-feature MMN paradigm [Näätänen R, Pakarinen S, Rinne T, Takegata R. The mismatch negativity (MMN): towards the optimal paradigm. Clin Neurophysiol 2004;115:140-144]. METHODS: MMN responses to changes in sound duration, frequency, intensity, and perceived sound-source location at six different magnitudes of deviation were recorded from healthy young adults by using the multi-feature MMN paradigm. In addition, behavioural discrimination accuracy and speed were measured to examine the relationship between MMN and behavioural performance. RESULTS: All the 24 sound changes elicited significant MMNs. MMN amplitude increased and latency decreased with increasing magnitude of sound change. Furthermore, the MMN amplitude and latency predicted the subjects' accuracy and speed in detecting these deviations. CONCLUSIONS: This new paradigm provides an extensive auditory discrimination profile for several auditory attributes at different deviation magnitudes in a minimal recording time. SIGNIFICANCE: The auditory discrimination profiles can offer a comprehensive view of the development, plasticity, and deficits of central auditory processing.

Acoustic Stimulation↗

PubMed2006

Inherited auditory-cortical dysfunction in twin pairs discordant for schizophrenia.

BACKGROUND: Information on the inheritance of neurophysiological abnormalities might help elucidate the molecular genetic basis of schizophrenia. We used magnetoencephalography (MEG) and electroencephalography (EEG) to investigate the inheritance of auditory-cortical deficiencies in twin pairs discordant for schizophrenia. METHODS: Auditory EEG/MEG responses to frequent standard and occasional deviant tones were measured in mono- and dizygotic (MZ and DZ) twin pairs discordant for schizophrenia and demographically matched healthy twin pairs, recruited from a total population cohort. The MEG/EEG results were regressed against the genetic resemblance to patients with schizophrenia across the patients' unaffected MZ/DZ co-twins and control subjects (with genetic correlations of 1, .5, and 0 to schizophrenia patients, respectively). RESULTS: The EEG responses P50, N100, and mismatch negativity (MMN), as well as the MEG response P50m, were reduced in the schizophrenic patients. P50 and N100 were significantly decreased also in their unaffected co-twins, as compared with the control subjects. Importantly, the P50 and N100 decrease correlated with the unaffected subjects' genetic resemblance to schizophrenia patients. CONCLUSIONS: Our results suggest inherited abnormalities in cortical auditory processing in schizophrenia, reflected by the decreased P50/P50m and N100 amplitudes, whereas the MMN abnormalities might reflect predominantly state-dependent neurodegeneration.

Brain Mapping↗

PubMed2005

Does sleep quality affect involuntary attention switching system?

We studied the relationship between sleep quality and quantity and subsequently recorded automatically evoked event-related potential (ERP) responses. In previous studies decrement of attentional processing has been associated with changes in sleep. Sleep is shown to associate also with ERPs elicited by unattended sound stream, however, there is no consensus on these effects. A recent study suggested that the early anterior P3a to novel stimuli in attended stream is attenuated and the late parietal P3a is strengthened by total sleep deprivation. We carried out 72-h consecutive actigraphy measurements in a naturalistic setting to collect information about variation in sleep duration, sleep onset latency, sleep efficiency, and percentage of sleep. MMN and P3a deflections to infrequent changes in sound duration and pitch in unattended sound stream were obtained in a separate recording session from the same subjects when they were awake. No significant correlations were found between sleep and MMN parameters, indicating that MMN is resistant to normal variation in sleep. However, P3a to both pitch and duration changes correlated positively with sleep onset latency, and P3a to duration changes correlated negatively with sleep efficiency and percentage of sleep. The correlation was higher in the posterior scalp areas. Our results suggest that the involuntary attention switching system, reflected by the P3a is sensitized as a function of decreased sleep quality.

Acoustic Stimulation↗

PubMed2004

The mismatch negativity (MMN): towards the optimal paradigm.

OBJECTIVE: Recent studies have shown that the mismatch negativity (MMN), a change-specific component of the event-related potential (ERP), for particular auditory features is degraded in different clinical populations. This suggests that the MMN could, in principle, reflect the whole profile and extent of the central auditory deficit. In the present article, we tested a new MMN paradigm allowing one to obtain MMNs for several auditory attributes in a short time. METHODS: MMN responses to changes in frequency, intensity, duration, location, and to a silent gap occasionally inserted in the middle of a tone were compared between the traditional 'oddball' paradigm (a single type of auditory change in each sequence) and the new paradigm (two versions) in which all the 5 types of changes appeared within the same sequence. RESULTS: The MMNs obtained in the new paradigm were equal in amplitude to those in the traditional MMN paradigm. CONCLUSIONS: We propose a new paradigm that can provide 5 different MMNs in the same time in which usually only one MMN is obtained. The new paradigm enables one to objectively determine the profile of different auditory discrimination abilities within a very short recording time.

Acoustic Stimulation↗