Brain mechanisms of auditory-motor integration and learning

点击翻译按钮获取中文摘要

The brain networks for visual-motor integration are well studied, producing the dorsal stream model of vision for action in which information from visual areas is transformed in parietal cortex, and fed to premotor regions to plan a motor response. Researchers are now exploring the neural mechanisms linking auditory perception and motor response, particularly for music and speech. It is proposed that specific pathways in the dorsal stream link auditory information and motor plans, underwriting the feed-forward and feedback control required for speaking or playing an instrument. ***   We have shown that even for people with no training, motor regions - including the premotor cortex (PMC) and basal ganglia (BG) - are active when listening to music. We also know that simply listening to melodies that are congruent with a motor sequence can facilitate learning. These findings suggest that there are intrinsic interactions between the auditory and motor systems. Further, we have shown that parietal regions known to compute visual-motor transformations are engaged when learning new melodies. Finally, there is evidence that different regions of the BG are important for prediction and pleasure for musical rhythm. ***The goal of the proposed research is to test the contributions of auditory, motor and striatal regions - and their interactions - to auditory-motor integration in the context of learning.*** ***Aim 1: fMRI and TMS will be used to assess the contributions of auditory and motor regions to motor learning with purely auditory training. We hypothesize that melody learning will lead to enhanced performance of a congruent motor sequence and greater coupling of activity in auditory, PMC and parietal regions. TMS will test the role of PMC in acquiring the auditory-motor associations thought to underlie transfer from auditory to motor learning. ***Aim 2: fMRI will be used to investigate how skilled and novice musicians use auditory and motor information to learn new melodies. We hypothesize that when musicians learn they first engage PMC and cerebellar feed-forward mechanisms to improve accuracy, and later engage auditory and parietal based feedback mechanisms to fine-tune performance. In contrast, new learners rely more on motor information and feedback control.***Aim 3: Behavioral and fMRI experiments will test the role of the PMC and specific BG in temporal prediction and reward processing in the context of musical rhythm. We hypothesize that PMC is important for extracting temporal regularity and that the putamen is engaged in prediction once a regular pattern is identified. Further, we hypothesize that the dorsal part of the ventral striatum is involved in pleasure and reward for musical beat. ***This work will generate important new information about the brain mechanisms underlying the integration of sound and movement, and will provide a critical test of dorsal stream theories of auditory-motor integration based on vision.*** ***********