Description
Understanding how sounds are processed in the brain is important in many clinical conditions, psychiatric symptoms and language acquisition. The aim of the base research of the Project is to study the electrophysiology of auditory perception, evaluate the effect of cognitive training and compare language groups. It provides means to evaluate the structural, neural and metabolic mechanisms of auditory perception and create tools applicable in clinical practice and special groups of population. The research will result in 5 international peer-reviewed publications. The Project is significant to the whole society, especially various language and clinical groups, by providing applicable solutions to assess auditory processing. The partnership with the Bergen fMRI group (Donor Partner) includes sharing study protocols, implementing one another`s expertise in experimental techniques, experiments parallel in both laboratories with different language groups and building bilateral relations.
Summary of project results
The ability to understand spoken language is so essential that we hardly recognize how extraordinary this cognitive process is. The sounds that reach our ear, are transformed into a conscious representation of meaningful speech in mere milliseconds. We effortlessly extract the semantic and syntactic information, but also the location, mood, age, gender, social status and even more about the speaker. We only consciously notice speech processing when it does not function the way it should. Trying to understand speech in a foreign language, struggling to keep up conversation at a loud party, or even hearing “voices” talking to you that are not really there – these are examples of various situations where our auditory system is challenged beyond its comfort zone. In this project, the researchers explored the fundamental mechanisms that enable our brains to process auditory sounds. The mechanisms of cortical plasticity following training are important to study due to their importance for learning and memory, as well as possibilities for intervention in case of disturbances in sensory processing. In language with clear distinction between voiced and unvoiced consonants perceivers are more sensitive to the voicing properties in speech. These results are important for diagnostic tools or study protocols where language-related material is used. To clarify which stimuli to use in clinical and laboratory settings, natural and computer-based synthesized stimuli were compared. The knowledge from the base research of the project will lay the groundwork for creating specific tools applicable in clinical practice (e.g. for quickly evaluating the effect of cognitive training on the plasticity of auditory cortex and brain plasticity in general; determining which specific cognitive training protocols are valid and reliable; comparing patient and non-patient groups) and in special groups of population (e.g. for effective language study protocols for non-native speakers and immigrants). Project results have been presented at various scientific conferences and seminars throughout the years. There have been seven scientific conference presentations, four seminar presentations at both Project Partners’ laboratories and two public information activities (at the Researchers’ Night Festival in Tartu in 2014 and 2015, where the Project and its methods were introduced to the general public).
Summary of bilateral results
This project clearly benefits from the Norwegian involvement, and the studies with the dichotic listening paradigm of Hugdhal give another dimension to the results. This definitely adds value and it will be interesting to see how this develops in future work from both labs, as the two techniques (mismatch negativity (MMN) and dichotic listening (DL)) both have different strengths. This collaboration also permits the study of languages which make different demands of the auditory system, and this is a terrific advantage. The partnership between the Project Promoter`s and Project Partner`s scientific institutions and researchers has led to synchronizing study protocols, which in turn helps to disentangle the emerging scientific questions more efficiently and quickly by using the knowledge and, if needed, facilities, of both partners. The partnership straightforwardly supported achieving the Project’s objectives and results. The expertise of the two participating laboratories was combined and the methodological approaches applied in the Project were built on the available resources of the partners. For answering the questions related to auditory and language processing, it is important to be able to measure the precise timing of the processes (using EEG), their behavioural correlates, as well as the underlying metabolic and functional status (possible with the magnetic resonance (MR) techniques). Project Partner, the Bergen fMRI group, has contributed specific methodological aspects. The group has extensive experience in MR imaging of auditory speech processing, and MR data analysis methods. The contribution has consisted of advancement of knowledge on applications of various MR techniques in cognitive research that were also applied in the joint study concerning glutamatergic neurotransmission in relation to MMN. Secondly the Bergen fMRI group has wide knowledge of and practice in using the dichotic listening (DL) paradigm, a measure of perceptual laterality, and experience in its applications (including neural correlates, training effects, clinical applications and adaptation to smartphone application for large-scale data collection). They have contributed to the implementation of the DL methodology in the experimental research in the Institute of Psychology at the University of Tartu by providing the basis of the experimental program, consulting about the specific details of the paradigm as well as choice of stimuli.