Feel the Noise: Relating Individual Differences in Auditory Imagery to the Structure and Function of Sensorimotor Systems.

César F Lima,Dana Boebinger,Pradheep Shanmugalingam,Andrea R Halpern,Sophie Meekings,Jane E Warren,Markus Ostarek,Samuel Evans,Nadine Lavan,Sophie K Scott,Carolyn Mcgettigan,Zarinah Agnew

doi:10.1093/cercor/bhv134

Abstract

Humans can generate mental auditory images of voices or songs, sometimes perceiving them almost as vividly as perceptual experiences. The functional networks supporting auditory imagery have been described, but less is known about the systems associated with interindividual differences in auditory imagery. Combining voxel-based morphometry and fMRI, we examined the structural basis of interindividual differences in how auditory images are subjectively perceived, and explored associations between auditory imagery, sensory-based processing, and visual imagery. Vividness of auditory imagery correlated with gray matter volume in the supplementary motor area (SMA), parietal cortex, medial superior frontal gyrus, and middle frontal gyrus. An analysis of functional responses to different types of human vocalizations revealed that the SMA and parietal sites that predict imagery are also modulated by sound type. Using representational similarity analysis, we found that higher representational specificity of heard sounds in SMA predicts vividness of imagery, indicating a mechanistic link between sensory- and imagery-based processing in sensorimotor cortex. Vividness of imagery in the visual domain also correlated with SMA structure, and with auditory imagery scores. Altogether, these findings provide evidence for a signature of imagery in brain structure, and highlight a common role of perceptual–motor interactions for processing heard and internally generated auditory information.

Highlights

Imagine the voice of a close friend when you laugh together, or a piano playing your favorite song
Combining voxel-based morphometry and functional magnetic resonance imaging (fMRI), we examined the structural basis of interindividual differences in how auditory images are subjectively perceived, and explored associations between auditory imagery, sensory-based processing, and visual imagery
A first whole-brain analysis focusing on the total imagery ratings revealed that higher ratings correlated with larger gray matter volume in a cluster with a peak voxel in the left paracentral lobule, extending to the right paracentral lobule, left precuneus, and left superior frontal gyrus (cluster size = 3369 voxels, PFWE = 0.03; Montreal Neurological Institute (MNI) coordinate for peak voxel: x = −8, y = −12, z = 69, t(1,67) = 3.63, Z = 3.45, P < 0.001 uncorrected)

Summary

Introduction

Imagine the voice of a close friend when you laugh together, or a piano playing your favorite song. Auditory imagery is a complex process by which an individual generates and processes mental images in the absence of sound perception—“hearing with the mind’s ear.”. Auditory mental images can be so vivid that they resemble the real experience of hearing, and they can be as accurate as representations arising directly from sensory input (Janata 2012). They facilitate several cognitive and motor processes. Functional neuroimaging studies have shown that the network of brain regions engaged during auditory imagery minimally includes the superior temporal gyri (STG), parietal, motor, and premotor cortices, the inferior frontal gyrus, and the supplementary motor area (SMA) (Shergill et al 2001; Herholz et al 2012; Zvyagintsev et al 2013; for a meta-analysis, McNorgan 2012)

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