Children show hemispheric differences in the basic auditory response properties

Abstract

Auditory cortex in each hemisphere shows preference to sounds from the opposite hemifield in the auditory space. Besides this contralateral dominance, the auditory cortex shows functional and structural lateralization, presumably influencing the features of subsequent auditory processing. Children have been shown to differ from adults in the hemispheric balance of activation in higher‐order auditory based tasks. We studied, first, whether the contralateral dominance can be detected in 7‐ to 8‐year‐old children and, second, whether the response properties of auditory cortex in children differ between hemispheres. Magnetoencephalography (MEG) responses to simple tones revealed adult‐like contralateral preference that was, however, extended in time in children. Moreover, we found stronger emphasis towards mature response properties in the right than left hemisphere, pointing to faster maturation of the right‐hemisphere auditory cortex. The activation strength of the child‐typical prolonged response was significantly decreased with age, within the narrow age‐range of the studied child population. Our results demonstrate that although the spatial sensitivity to the opposite hemifield has emerged by 7 years of age, the population‐level neurophysiological response shows salient immature features, manifested particularly in the left hemisphere. The observed functional differences between hemispheres may influence higher‐level processing stages, for example, in language function.

Child specific activation in left auditory cortex predicts behavioral performance in inhibition tasks

“…This protracted development of the left hemisphere arguably provides a time window where the brain can flexibly employ its resources which should be useful in the everchanging environment of the child brain. Indeed, others have argued for stronger experience-driven plasticity in the left-hemisphere (Renvall et al, 2012; Parviainen et al, 2019). However, handedness has also been shown to affect hemispheric dominance of neuromagnetic responses to sounds (Kirveskari et al, 2006) and as such our reported effect might depend on handedness.…”

“…Indeed, children show an auditory evoked response (i.e. N250m) that is reported even by passive stimulation, using different sound types, and under different attentional conditions (van Bijnen et al, 2019; Parviainen et al, 2019; Albrecht et al, 2000; Takeshita et al, 2002; Johnstone et al, 1996). This response is typically absent in adults.…”

“…N100) – and a lower letter “m” to indicate their MEG counterparts. In contrast, the most prominent responses in primary school children (∼6–12 years) are the P1(m) at around 100ms (Orekhova et al, 2013; Yoshimura et al, 2014) and a sustained activation pattern at ∼250 ms (N2m/N250m) (Paetau et al, 1995; Pontont et al, 2000; Ceponiene et al, 2002; Parviainen et al, 2019). The development of the auditory neural activation is best characterized by a gradual dissociation of the earlier, more transient responses (P1/N1), and an attenuation of the later, sustained, response (N250) until it is no longer or barely present in adults (Ponton et al, 2000; Albrecht et al, 2000; Čeponienė et al, 2002; Takeshita et al, 2002; Wunderlich and Cone-Wesson, 2006).…”

“…The development of the auditory neural activation is best characterized by a gradual dissociation of the earlier, more transient responses (P1/N1), and an attenuation of the later, sustained, response (N250) until it is no longer or barely present in adults (Ponton et al, 2000; Albrecht et al, 2000; Čeponienė et al, 2002; Takeshita et al, 2002; Wunderlich and Cone-Wesson, 2006). The right hemisphere seems to precede the left hemisphere in this developmental trajectory, suggesting faster maturation of the right-auditory cortex and possibly stronger experience-driven plasticity in the left than right hemisphere (Parviainen et al, 2019).…”

“…These two time-windows seem to represent functionally distinct processes. First, they are dissociated by their developmental trajectories (Parviainen et al, 2019). Second, responses in these time-windows show different refractory periods; whereas shortening the inter stimulus interval (ISI) attenuates the earlier response pattern, the later, more sustained response is enhanced (or unaffected) (Takeshita et al, 2002; Karhu et al, 1997).…”