Browsing by Subject "HUMAN AUDITORY-CORTEX"

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  • Virtala, Paula; Huotilainen, Minna; Lilja, Esa; Ojala, Juha; Tervaniemi, Mari (2018)
    GUITAR DISTORTION USED IN ROCK MUSIC MODIFIES a chord so that new frequencies appear in its harmonic structure. A distorted dyad (power chord) has a special role in heavy metal music due to its harmonics that create a major third interval, making it similar to amajor chord. We investigated how distortion affects cortical auditory processing of chords in musicians and nonmusicians. Electric guitar chords with or without distortion and with or without the interval of the major third (i.e., triads or dyads) were presented in an oddball design where one of them served as a repeating standard stimulus and others served as occasional deviants. This enabled the recording of event-related potentials (ERPs) of the electroencephalogram (EEG) related to deviance processing (the mismatch negativity MMN and the attention-related P3a component) in an ignore condition. MMN and P3a responses were elicited in most paradigms. Distorted chords in a non-distorted context only elicited early P3a responses. However, the power chord did not demonstrate a special role in the level of the ERPs. Earlier and larger MMN and P3a responses were elicited when distortion was modified compared to when only harmony (triad vs. dyad) was modified between standards and deviants. The MMN responses were largest when distortion and harmony deviated simultaneously. Musicians demonstrated larger P3a responses than nonmusicians. The results suggest mostly independent cortical auditory processing of distortion and harmony in Western individuals, and facilitated chord change processing in musicians compared to nonmusicians. While distortion has been used in heavy rock music for decades, this study is among the first ones to shed light on its cortical basis.
  • Alsius, Agnes; Möttönen, Riikka; Sams, Mikko E.; Soto-Faraco, Salvador; Tiippana, Kaisa (2014)
  • Rinne, Teemu; Muers, Ross S.; Salo, Emma; Slater, Heather; Petkov, Christopher I. (2017)
    The cross-species correspondences and differences in how attention modulates brain responses in humans and animal models are poorly understood. We trained 2 monkeys to perform an audio-visual selective attention task during functional magnetic resonance imaging (fMRI), rewarding them to attend to stimuli in one modality while ignoring those in the other. Monkey fMRI identified regions strongly modulated by auditory or visual attention. Surprisingly, auditory attention-related modulations were much more restricted in monkeys than humans performing the same tasks during fMRI. Further analyses ruled out trivial explanations, suggesting that labile selective-attention performance was associated with inhomogeneous modulations in wide cortical regions in the monkeys. The findings provide initial insights into how audio-visual selective attention modulates the primate brain, identify sources for "lost" attention effects in monkeys, and carry implications for modeling the neurobiology of human cognition with nonhuman animals.
  • Hari, Riitta; Baillet, Sylvain; Barnes, Gareth; Burgess, Richard; Forss, Nina; Gross, Joachim; Hämäläinen, Matti; Jensen, Ole; Kakigi, Ryusuke; Mauguière, François; Nakasato, Nobukatzu; Puce, Aina; Romani, Gian-Luca; Schnitzler, Alfons; Taulu, Samu (2018)
    Magnetoencephalography (MEG) records weak magnetic fields outside the human head and thereby provides millisecond-accurate information about neuronal currents supporting human brain function. MEG and electroencephalography (EEG) are closely related complementary methods and should be interpreted together whenever possible. This manuscript covers the basic physical and physiological principles of MEG and discusses the main aspects of state-of-the-art MEG data analysis. We provide guidelines for best practices of patient preparation, stimulus presentation, MEG data collection and analysis, as well as for MEG interpretation in routine clinical examinations. In 2017, about 200 whole-scalp MEG devices were in operation worldwide, many of them located in clinical environments. Yet, the established clinical indications for MEG examinations remain few, mainly restricted to the diagnostics of epilepsy and to preoperative functional evaluation of neurosurgical patients. We are confident that the extensive ongoing basic MEG research indicates potential for the evaluation of neurological and psychiatric syndromes, developmental disorders, and the integrity of cortical brain networks after stroke. Basic and clinical research is, thus, paving way for new clinical applications to be identified by an increasing number of practitioners of MEG. (C) 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V.
  • Tiainen, Mikko; Tiippana, Kaisa; Paavilainen, Petri; Vainio, Martti; Vainio, Lari (2017)
    Manual actions and speech are connected: for example, grip execution can influence simultaneous vocalizations and vice versa. Our previous studies show that the consonant [k] is associated with the power grip and the consonant [t] with the precision grip. Here we studied whether the interaction between speech sounds and grips could operate already at a pre-attentive stage of auditory processing, reflected by the mismatch-negativity (MMN) component of the event-related potential (ERP). Participants executed power and precision grips according to visual cues while listening to syllable sequences consisting of [ke] and [te] utterances. The grips modulated the MMN amplitudes to these syllables in a systematic manner so that when the deviant was [ke], the MMN response was larger with a precision grip than with a power grip. There was a converse trend when the deviant was [te]. These results suggest that manual gestures and speech can interact already at a pre-attentive processing level of auditory perception, and show, for the first time that manual actions can systematically modulate the MMN. (C) 2017 Elsevier B.V. All rights reserved.
  • Leminen, Alina; Verwoert, Maxime; Moisala, Mona; Salmela, Viljami; Wikman, Patrik; Alho, Kimmo (2020)
    In real-life noisy situations, we can selectively attend to conversations in the presence of irrelevant voices, but neurocognitive mechanisms in such natural listening situations remain largely unexplored. Previous research has shown distributed activity in the mid superior temporal gyrus (STG) and sulcus (STS) while listening to speech and human voices, in the posterior STS and fusiform gyrus when combining auditory, visual and linguistic information, as well as in left-hemisphere temporal and frontal cortical areas during comprehension. In the present functional magnetic resonance imaging (fMRI) study, we investigated how selective attention modulates neural responses to naturalistic audiovisual dialogues. Our healthy adult participants (N = 15) selectively attended to video-taped dialogues between a man and woman in the presence of irrelevant continuous speech in the background. We modulated the auditory quality of dialogues with noise vocoding and their visual quality by masking speech-related facial movements. Both increased auditory quality and increased visual quality were associated with bilateral activity enhancements in the STG/STS. In addition, decreased audiovisual stimulus quality elicited enhanced fronto-parietal activity, presumably reflecting increased attentional demands. Finally, attention to the dialogues, in relation to a control task where a fixation cross was attended and the dialogue ignored, yielded enhanced activity in the left planum polare, angular gyrus, the right temporal pole, as well as in the orbitofrontal/ventromedial prefrontal cortex and posterior cingulate gyrus. Our findings suggest that naturalistic conversations effectively engage participants and reveal brain networks related to social perception in addition to speech and semantic processing networks.
  • Heikkila, Jenni; Tiippana, Kaisa; Loberg, Otto; Leppänen, Paavo H. T. (2018)
    Seeing articulatory gestures enhances speech perception. Perception of auditory speech can even be changed by incongruent visual gestures, which is known as the McGurk effect (e.g., dubbing a voice saying /mi/ onto a face articulating /ni/, observers often hear /ni/). In children, the McGurk effect is weaker than in adults, but no previous knowledge exists about the neural-level correlates of the McGurk effect in school-age children. Using brain event-related potentials, we investigated change detection responses to congruent and incongruent audiovisual speech in school-age children and adults. We used an oddball paradigm with a congruent audiovisual /mi/ as the standard stimulus and a congruent audiovisual /ni/ or McGurk A/mi/V/ni/ as the deviant stimulus. In adults, a similar change detection response was elicited by both deviant stimuli. In children, change detection responses differed between the congruent and the McGurk stimulus. This reflects a maturational difference in the influence of visual stimuli on auditory processing.
  • Hakonen, Maria; May, Patrick J. C.; Jaaskelainen, Iiro P.; Jokinen, Emma; Sams, Mikko; Tiitinen, Hannu (2017)
    Introduction: We examined which brain areas are involved in the comprehension of acoustically distorted speech using an experimental paradigm where the same distorted sentence can be perceived at different levels of intelligibility. This change in intelligibility occurs via a single intervening presentation of the intact version of the sentence, and the effect lasts at least on the order of minutes. Since the acoustic structure of the distorted stimulus is kept fixed and only intelligibility is varied, this allows one to study brain activity related to speech comprehension specifically. Methods: In a functional magnetic resonance imaging (fMRI) experiment, a stimulus set contained a block of six distorted sentences. This was followed by the intact counterparts of the sentences, after which the sentences were presented in distorted form again. A total of 18 such sets were presented to 20 human subjects. Results: The blood oxygenation level dependent (BOLD)-responses elicited by the distorted sentences which came after the disambiguating, intact sentences were contrasted with the responses to the sentences presented before disambiguation. This revealed increased activity in the bilateral frontal pole, the dorsal anterior cingulate/paracingulate cortex, and the right frontal operculum. Decreased BOLD responses were observed in the posterior insula, Heschl's gyrus, and the posterior superior temporal sulcus. Conclusions: The brain areas that showed BOLD-enhancement for increased sentence comprehension have been associated with executive functions and with the mapping of incoming sensory information to representations stored in episodic memory. Thus, the comprehension of acoustically distorted speech may be associated with the engagement of memory-related subsystems. Further, activity in the primary auditory cortex was modulated by prior experience, possibly in a predictive coding framework. Our results suggest that memory biases the perception of ambiguous sensory information toward interpretations that have the highest probability to be correct based on previous experience.