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The present study investigates hemispheric asymmetry of the ERPs and low-frequency oscillatory responses evoked in both hemispheres of the brain by the sound stimuli with delayed onset of motion. EEG was recorded for three patterns of sound motion produced by changes in interaural time differences. Event-related spectral perturbation (ERSP) and inter-trial phase coherence (ITC) were computed from the time-frequency decomposition of EEG signals. The participants either read books of their choice (passive listening) or indicated the sound trajectories perceived using a graphic tablet (active listening). Our goal was to find out whether the lateralization of the motion-onset response (MOR) and oscillatory responses to sound motion were more consistent with the right-hemispheric dominance, contralateral or neglect model of interhemispheric asymmetry. Apparent dominance of the right hemisphere was found only in the ERSP responses. Stronger contralaterality of the left hemisphere corresponding to the "neglect model" of asymmetry was shown by the MOR components and by the phase coherence of the delta-alpha oscillations. Velocity and attention did not change consistently the interhemispheric asymmetry of both the MOR and the oscillatory responses. Our findings demonstrate how the lateralization pattern shown by the MOR potential was interrelated with that of the motion-related single-trial measures., (Copyright © 2020 Elsevier B.V. and Japan Neuroscience Society. All rights reserved.)

The current MMN study investigates whether brain lateralization during automatic discrimination of sound stimuli moving at different velocities is consistent with one of the three models of asymmetry: the right-hemispheric dominance model, the contralateral dominance model, or the neglect model. Auditory event-related potentials (ERPs) were recorded for three patterns of sound motion produced by linear or abrupt changes of interaural time differences. The slow motion (450deg/s) was used as standard, and the fast motion (620deg/s) and the abrupt sound shift served as deviants in the oddball blocks. All stimuli had the same onset/offset spatial positions. We compared the effects of the recording side (left, right) and of the direction of sound displacement (ipsi- or contralateral with reference to the side of recording) on the ERPs and mismatch negativity (MMN). Our results indicated different patterns of asymmetry for the ERPs and MMN responses. The ERPs showed a velocity-independent right-hemispheric dominance that emerged at the descending limb of N1 wave (at around 120-160ms) and could be related to overall context of the preattentive spatial perception. The MMNs elicited in the left hemisphere (at around 230-270ms) exhibited a contralateral dominance, whereas the right-hemispheric MMNs were insensitive to the direction of sound displacement. These differences in contralaterality between MMN responses produced by the left and the right hemisphere favour the neglect model of the preattentive motion processing indexed by MMN., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

This study investigated the energy-onset and motion-onset responses (N1, P2, cN 1 and cP2 components of the auditory evoked potential) elicited by moving sound stimuli in the passive and active listening conditions. In the passive conditions the subjects were distracted from auditory information; in active conditions they lo- calized the starting and final points of the stimulus trajectory. The sound movement to the left/right from the head midline was produced by linear-changes of the interaural time delay (ITD). The onset of motion was preceded by stationary sound located near the head midline. In the active conditions, the NI component was higher and the P2 component was higher and peaked later as compared to the passive listening. The early and later parts of the motion-onset response (cN 1 and cP2) also were larger in magnitude and peaked later during active listening. Both in active and passive conditions, cNI and cP2 amplitude exhibited increase and latency showed decrease when the stimulus velocity increased. Contralateral asymmetry was found only in the mo- tion-onset responses recorded from the left hemisphere.

The spectral dynamics of the EEG rhythmicity during active and passive discrimination of stationary and moving sound stimuli presented according to the oddball paradigm were investigated. Standard stimuli represented stationary midline sounds. Deviant stimuli simulated smooth and stepwise sound source motion (to the left/right from head midline) produced by linear and stepwise changes of interaural time delay. Significant changes of the brain oscillations were found in the frequency range of 3-30 Hz. The dynamics of the moving deviant stimuli (smooth vs. stepwise) had greater impact on theta-rhythm power in active listening conditions: a stronger theta-power increase was evoked by the stepwise sound motion as compared to smooth motion. Significant increase in theta-power was also observed with rightward sound displacement as compared to leftward displacements. Active deviant discrimination reduced alpha-power (8-11 Hz) mostly during smooth deviant motion. The power increase of lower alpha-oscillations (12-15 Hz) was stronger with step- wise motion than with smooth motion of deviants. The interhemispheric asymmetry of beta-power decrease in active conditions (as compared to passive) was found in the whole beta-range. The sup- pression of beta-power was stronger at the right hemisphere than at the midline or left hemisphere and showed no dependence on spatial properties of the deviant stimuli. This asymmetry may be related to selective attention to task-relevant sounds and with preparation to motor response. Generally, active auditory discrimination resulted in stronger deviant-related changes of the wide-ranged EEG spectral power than passive discrimination with attentional tuning to task-irrelevant stimuli.

The current study investigates auditory event-related potentials (ERPs) and mismatch negativity (MMN) during active and passive discrimination of stationary and moving sound stimuli presented according to the oddball paradigm. Standard stimuli represented stationary midline sounds. Deviant stimuli simulated sound source location shifts (to the left/right from head midline) produced by linear or stepwise changes of interaural time delay (ITD). The event-related responses were evaluated by peak amplitudes of N1 waves and mean amplitudes of MMN, P3a, P3b and reorienting negativity (RON) components. The N1 amplitude was larger in active than in passive conditions, and was unaffected by spatial dynamic changes of the deviant stimuli. The deviant motion pattern (smooth or stepwise) affected only MMN and RON obtained in passive listening conditions. Abrupt deviant displacement elicited larger MMN and RON components than smooth motion. Drawing listeners' attention to the deviant stimuli resulted in suppression of MMN/RON sensitivity to auditory motion pattern.

The present study investigates the hemispheric asymmetry of auditory event-related potentials (ERPs) and mismatch negativity (MMN) during passive discrimination of the moving sound stimuli presented according to the oddball paradigm. The sound movement to the left/right from the head midline was produced by linear changes of the interaural time delay (ITD). It was found that the right-hemispheric N1 and P2 responses were more prominent than the left-hemispheric ones, especially in the fronto-lateral region. On the contrary, N250 and MMN responses demonstrated contralateral dominance in the fronto-lateral and fronto-medial regions. Direction of sound motion had no significant effect on the ERP or MMN topography. The right-hemispheric asymmetry of N1 increased with sound velocity. Maximal asymmetry of P2 was obtained with short stimulus trajectories. The contralateral bias of N250 and MMN increased with the spatial difference between standard and deviant stimuli. The results showed different type of hemispheric asymmetry for the early and late ERP components which could reflect the activity of distinct neural populations involved in the sensory and cognitive processing of the auditory input.

The magnitude of spatial distance between sound stimuli is critically important for their preattentive discrimination, yet the effect of stimulus context on auditory motion processing is not clear. This study investigated the effects of acoustical change and stimulus context on preattentive spatial change detection. Auditory event-related potentials (ERPs) were recorded for stationary midline noises and two patterns of sound motion produced by linear or abrupt changes of interaural time differences. Each of the three types of stimuli was used as standard or deviant in different blocks. Context effects on mismatch negativity (MMN) elicited by stationary and moving sound stimuli were investigated by reversing the role of standard and deviant stimuli, while the acoustical stimulus parameters were kept the same. That is, MMN amplitudes were calculated by subtracting ERPs to identical stimuli presented as standard in one block and deviant in another block. In contrast, effects of acoustical change on MMN amplitudes were calculated by subtracting ERPs of standards and deviants presented within the same block. Preattentive discrimination of moving and stationary sounds indexed by MMN was strongly dependent on the stimulus context. Higher MMNs were produced in oddball configurations where deviance represented increments of the sound velocity, as compared to configurations with velocity decrements. The effect of standard-deviant reversal was more pronounced with the abrupt sound displacement than with gradual sound motion., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The parallel psychophysical and MMN study focused at the sensitivity of human hearing system to variations in velocity of sound image movement. The motion of sound stimuli with various velocities in the 450 deg/s to 732 deg/s range in increments of 6 deg/s to the left or to the right from the head midline was simulated by introducing linear changes of interaural delay into dichotic stimuli. The psychophysical experiments were designed according to the 2-alternative forced choice paradigm. The subjects were presented by pairs of moving stimuli and were asked to decide which moved faster. The stimuli created for the present study ensured that the subjects performed the discrimination task without relying on associated cues of sound displacement or duration. The psychophysical measures were compared with electrophysiological indexes of sound processing (auditory evoked responses (ERPs) and mismatch negativity (MMN)). Significant MMN was elicited by the difference of 170 deg/s between the reference and test velocity, which corresponded to the relative velocity increase of 38%. At the same time, the difference thresholds for velocity were much higher and exceeded 50%. The results suggest that MMN magnitude depended on the velocity difference between standard and deviant stimuli and was more sensitive to velocity difference than psychophysical measure.

The study focused at the objective and subjective indexes of human hearing system sensitivity towards different types of moving sound stimuli. The experiment employed two methods: electrophysiological (MMN recording) and psychophysical method (two-alternative forced choice). Two types of spatial sound stimuli simulated gradual and abrupt sound motion from the head midline. MMN as an objective index of spatial discrimination has been obtained in response to the subthreshold and the suprathreshold stimuli. An increase of trajectory length of the moving stimuli resulted in an increase of the MMN amplitude and of subjective discrimination as well, although their correlation remained below the significance level. The results obtained are discussed from the point of view of preconscious perception of auditory spatial information.

Auditory evoked response and mismatch negativity potential have been studied using the reversed odd-ball paradigm of standard and deviant stimulus presentation. In the experiments, three types of spatial sound stimuli (stationary and moving either gradually or abruptly from the head midline) were presented in three configurations. Each configuration employed one stimulus type as standard and the other two types as deviants. It was demonstrated that the configuration reversals influenced significantly the evoked response and mismatch negativity. The results obtained are discussed as the possible evidence of the categorical perception of auditory motion revealed at the earlier stages of sound processing in the hearing system.

The review presents the data concerning auditory event-related potentials and their "mismatch negativity" component under conditions of stationary and moving sound source localization. Both free-field and dichotic experimental conditions are considered. The interhemispheric asymmetry of the brain responses elicited by the sound sources of various spatial properties is also discussed.

The ability to localize endpoints of sound image trajectories was studied in comparison with stationary sound image positions. Sound images moved either gradually or abruptly to the left or right from the head midline. Different types of sound image movement were simulated by manipulating the interaural time delay. Subjects were asked to estimate the position of the virtual sound source, using the graphic tablet. It was revealed that the perceived endpoints of the moving sound image trajectories, like stationary stimulus positions, depended on the interaural time delay. The perceived endpoints of the moving sound images simulated by stimuli with the final interaural time delay lower than 200 micros were displaced further from the head midline as compared to stationary stimuli of the same interaural time delays. This forward displacement of the perceived position of the moving target can be considered as "representational momentum" and can be explained by mental extrapolation of the dynamic information, which is necessary for successive sensorimotor coordination. For interaural time delays above 400 micros, final positions of gradually and abruptly moving sound sources were closer to the head midline than corresponding stationary sound image position. When comparing the results of both duration conditions, it was shown that in case of longer stimuli the endpoints of gradually moving sound images were lateralized further from the head midline for interaural time delays above 400 micros.

Displacement of the perceived position of the starting points relative to the objective one during the moving sound source localization is an example of the auditory perception sluggishness. The ability to localize starting and end points of sound image trajectories was studied in comparison with stationary sound image positions. Sound images moved gradually or abruptly to the left or right from the head midline. The subjects were asked to estimate the position of the virtual sound source, using the graphic tablet. It was revealed that the starting points shifted systematically in the direction of the sound image movement. This tendency was stronger for the gradual movement then for the abrupt shift, and for shorter stimuli (100 ms) in comparison with longer ones (200 ms). The starting point displacement magnitude depended on the final value of the interaural time delay. The findings are discussed in view of the "snapshort" and "movement detectors" theories. The representational momentum and anticipation ability of the auditory perception were also considered.