The voice we most often hear is our own, and proper interaction between speaking and hearing is essential for both acquisition and performance of spoken language. Disturbed audiovocal interactions have been implicated in aphasia, stuttering, and schizophrenic voice hallucinations, but paradigms for a noninvasive assessment of auditory self-monitoring of speaking and its possible dysfunctions are rare. Using magnetoencephalograpy we show here that self-uttered syllables transiently activate the speaker's auditory cortex around 100 ms after voice onset. These phasic responses were delayed by 11 ms in the speech-dominant left hemisphere relative to the right, whereas during listening to a replay of the same utterances the response latencies were symmetric. Moreover, the auditory cortices did not react to rare vowel changes interspersed randomly within a series of repetitively spoken vowels, in contrast to regular change-related responses evoked 100-200 ms after replayed rare vowels. Thus, speaking primes the human auditory cortex at a millisecond time scale, dampening and delaying reactions to self-produced "expected" sounds, more prominently in the speech-dominant hemisphere. Such motor-to-sensory priming of early auditory cortex responses during voicing constitutes one element of speech self-monitoring that could be compromised in central speech disorders.

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Sivumäärä -Number of pages 70Tiivistelmä -Abstract Working memory (WM) is at the core of any cognitive function as it is necessary for the integration of information over time. Despite WM's critical role in high-level cognitive functions, its implementation in the neural tissue is poorly understood. Preliminary studies on auditory WM show differences between linguistic and musical memory, leading to the speculation of specific neural networks encoding memory for music. Moreover, in neuroscience WM has not been studied in naturalistic listening conditions but rather in artificial settings (e.g., n-back and Sternberg tasks). Western tonal music provides naturally occurring motivic repetition and variation, recognizable units serving as WM trigger, thus allowing us to study the phenomenon of motif-tracking in the context of real music. Adopting a modern tango as stimulus, behavioural methods were used to identify the stimulus motifs and build a time-course predictor of WM neural responses. This predictor was then correlated with the participants' functional magnetic resonance imaging (fMRI) signal obtained during a continuous listening condition. Neural correlates related to the sensory processing of a set of musical features were filtered out from the brain responses to music to aid in the exclusive recruitment of executive processes of music-related WM. Correlational analysis revealed a widely distributed network of cortical and subcortical areas, predominantly right-lateralized, responding to the WM condition, including ventral and dorsal areas in the prefrontal cortex, basal ganglia, and limbic areas. Significant subcortical processing areas, active in response to the WM condition, were pruned with the removal of the acoustic content, suggesting these music-related perceptual processing areas might aid in the encoding and retrieval of WM. The pattern of dispersed neural activity indicates WM to emerge coherently from the integration of distributed neural activity spread out over different brain subsystems (motoric-, cognitive-and sensory-related areas of the brain).Asiasanat -Keywords working memory; cognitive neuroscience; music; musical motifs; functional magnetic resonance imaging ( Lashley was attempting to identify the locus of memory within the cortex, and, to do so, first trained rats to run mazes, and then removed various cortical regions. He allowed the animals to recover and tested the retention of the maze-running skills. To his surprise it was not possible to find a particular region corresponding to the ability to remember the way through a maze. Instead all the rats which had had cortex regions removed suffered some kind of impairment, and the extent of the impairment was roughly proportional to the amount of cortex taken off. Removing cortex damaged the motor and sensory capacities of the animals, and they would limp, hop, roll, or stagger, but somehow they always managed to traverse the maze. So far as memory 'as concerned, the cortex appeared to be equipotential, that is, with all regions of eq...