Hemispheric asymmetry in mid and long latency neuromagnetic responses to single clicks

Abstract

We examine lateralization in the evoked magnetic field response to a click stimulus, observing that lateralization effects previously demonstrated for tones, noise, frequency modulated sweeps and certain syllables are also observed for (acoustically simpler) clicks. These effects include a difference in the peak latency of the M100 component of the evoked field waveform such that the peak consistently appears earlier in the right hemisphere, as well as rightward lateralization of field amplitude during the rise of the M100 component. Our review of previous findings on M100 lateralization, taken together with our data on the click-evoked response, leads to the hypothesis that these lateralization effects are elicited by stimuli containing a sharp sound energy onset or acoustic transition rather than specific types of stimuli. We argue that both the latency and the amplitude lateralization effects have a common origin, namely, hemispheric asymmetry in the amplitude of the magnetic field generated by one or more sources active during the M100 rise. While anatomical asymmetry cannot be excluded as the cause of the amplitude difference, we propose that the difference reflects a rightward asymmetry in the processing of sound energy onsets that potentially underlies the lateralization of several functions.

Differential cerebral reactivity to shortest and longer tones: Neuromagnetic and behavioral evidence

“…5 and 6), which suggested that the right hemisphere might be more superior in change detection compared to the left hemisphere. This was consistent with previous EEG and MEG studies (Paavilainen et al, 1991;McEvoy et al, 1993;Levänen et al, 1996;Howard and Poeppel, 2009). Several clinical and animal studies have also reported right hemispheric dominance in non-verbal sound processing and pitch discrimination (Zatorre, 1985;Zatorre and Samson, 1991).…”

The Analysis of Simple and Complex Auditory Signals in Human Auditory Cortex: Magnetoencephalographic Evidence From M100 Modulation

“…Typical MEG studies focusing on the M100 component use either simple sinusoidal signals or more complex speech tokens (e.g., synthetic vowels with three sinusoidal or approximately sinusoidal components) but do not examine how the individual simple components of a complex signal contribute to the overall M100 response of the complex signal. The data for the simple signals replicate previous findings, namely that as the signal level increases, the field deflection increases and the peak latency decreases and that the RH exhibits faster latencies than the LH (Stufflebeam et al 1998; Lütkenhöner & Klein 2007; Howard & Poeppel 2009). The analysis was performed in sensor space, not source space, to stay as close as possible to the recorded data without making source configuration assumptions.…”

Abnormal Pre-Attentive Arousal in Young Children with Autism Spectrum Disorder Contributes to Their Atypical Auditory Behavior: An ERP Study

“…The functional differences, however, are also likely to play a role. Thus, it has been suggested that sharp ramps of the sound may contribute to the rightward lateralization [92]. The other property of click stimulation that could contribute to the rightward P100 lateralization is its tendency to evoke phasic cortical arousal and potentially - re-orienting of spatial attention.…”