Atypical brain lateralisation in the auditory cortex and language performance in 3- to 7-year-old children with high-functioning autism spectrum disorder: a child-customised magnetoencephalography (MEG) study

Abstract

BackgroundMagnetoencephalography (MEG) is used to measure the auditory evoked magnetic field (AEF), which reflects language-related performance. In young children, however, the simultaneous quantification of the bilateral auditory-evoked response during binaural hearing is difficult using conventional adult-sized MEG systems. Recently, a child-customised MEG device has facilitated the acquisition of bi-hemispheric recordings, even in young children. Using the child-customised MEG device, we previously reported that language-related performance was reflected in the strength of the early component (P50m) of the auditory evoked magnetic field (AEF) in typically developing (TD) young children (2 to 5 years old) [Eur J Neurosci 2012, 35:644–650]. The aim of this study was to investigate how this neurophysiological index in each hemisphere is correlated with language performance in autism spectrum disorder (ASD) and TD children.MethodsWe used magnetoencephalography (MEG) to measure the auditory evoked magnetic field (AEF), which reflects language-related performance. We investigated the P50m that is evoked by voice stimuli (/ne/) bilaterally in 33 young children (3 to 7 years old) with ASD and in 30 young children who were typically developing (TD). The children were matched according to their age (in months) and gender. Most of the children with ASD were high-functioning subjects.ResultsThe results showed that the children with ASD exhibited significantly less leftward lateralisation in their P50m intensity compared with the TD children. Furthermore, the results of a multiple regression analysis indicated that a shorter P50m latency in both hemispheres was specifically correlated with higher language-related performance in the TD children, whereas this latency was not correlated with non-verbal cognitive performance or chronological age. The children with ASD did not show any correlation between P50m latency and language-related performance; instead, increasing chronological age was a significant predictor of shorter P50m latency in the right hemisphere.ConclusionsUsing a child-customised MEG device, we studied the P50m component that was evoked through binaural human voice stimuli in young ASD and TD children to examine differences in auditory cortex function that are associated with language development. Our results suggest that there is atypical brain function in the auditory cortex in young children with ASD, regardless of language development.

Sex-specific gene–environment interactions underlying ASD-like behaviors

“…Prolonged activation of CRHR1 in the hippocampus as a result of early stress affects the structure, synaptic function, and cognition (30,31), but we are not aware of any studies that have investigated the sex-specific effect of prenatal (immunological) stress on CRH or its receptors in the hippocampus. Because ASD is associated with changes in lateralization [behavioral study (32), MRI studies (33,34), magnetoencephalography study (35), and references in these studies], and many genes are asymmetrically expressed in the rodent hippocampus (36), we performed Crh, Crhr1, Crhr2, and Crhbp (corticotropin-releasing factor-binding protein) mRNA geneexpression assays on the two hemispheres separately. Because we found the strongest effects on Crhr1 mRNA expression in the left hippocampus, we then continued to investigate histone modifications on the promoter area of the Crhr1 gene in the left hippocampus.…”

Atypical Bilateral Brain Synchronization in the Early Stage of Human Voice Auditory Processing in Young Children with Autism

“…In previous MEG studies, this component has been alternatively labeled M100 or N100m; we here call this component "N1m." The main sources of the P1m and N1m are the auditory cortex and association cortices, and abnormalities in AEF components have been reported in patients with ASD [1][2][3][4][5][6][7][8][9][10][21][22][23][24][25]. Although many prior studies have focused on the aberrant intensity or latency of AEF components in children with ASD, no investigations have focused on the bilateral synchronization of AEF components in children with ASD.…”

“…Altered auditory processing systems in children with ASD have been studied as neurological correlates of some phenotypes in ASD, such as inhibited language acquisition [1][2][3][4][5][6][7][8] and auditory hypersensitivity [9][10][11], and previous studies that have focused on auditory responses of the brain have also demonstrated altered cerebral laterality [2,5,6] and regional connectivity [12] in children with ASD. These studies have indicated alterations in cortical auditory processes in ASD [1,2,4,5,9,10], whereas increased rates of brain stem or peripheral hearing dysfunction have also been reported in the ASD population [13][14][15][16][17][18][19][20].…”

“…AEFs recorded by MEG can clearly and easily distinguish bilateral brain responses evoked by binaural auditory stimuli. Thus, any unilateral abnormality or hemispheric difference can be accurately investigated by MEG [2]. The earliest cortical component of AEFs (i.e., P1m shown in Fig 1) is a prominent component in 1-to 10-year-old children [23,[31][32][33].…”

“…In the last decade, MEG has emerged as an important investigatory tool in neurodevelopmental studies because MEG has advantages over other neuroimaging techniques for young children, including safety, fewer constraints and less environmental noise. Using MEG, many recent studies have observed aberrant brain activities in children with ASD [1][2][3][4][5][6][7][8][9][10][21][22][23][24][25][26][27][28][29] by investigating brain connectivity [26,[28][29][30] or atypical brain responses to auditory stimuli [1][2][3][4][5][6][7][8][9][10][21][22][23][24][25].…”