Direction‐specific adaptation of motion‐onset auditory evoked potentials

Abstract

Auditory evoked potentials (AEPs) to motion onset in humans are dominated by a fronto-central complex, with a change-negative deflection 1 (cN1) and a change-positive deflection 2 (cP2) component. Here the contribution of veridical motion detectors to motion-onset AEPs was investigated with the hypothesis that direction-specific adaptation effects would indicate the contribution of such motion detectors. AEPs were recorded from 33 electroencephalographic channels to the test stimulus, i.e. motion onset of horizontal virtual auditory motion (60° per s) from straight ahead to the left. AEPs were compared in two experiments for three conditions, which differed in their history prior to the motion-onset test stimulus: (i) without motion history (Baseline), (ii) with motion history in the same direction as the test stimulus (Adaptation Same), and (iii) a reference condition with auditory history. For Experiment 1, condition (iii) comprised motion in the opposite direction (Adaptation Opposite). For Experiment 2, a noise in the absence of coherent motion (Matched Noise) was used as the reference condition. In Experiment 1, the amplitude difference cP2 - cN1 obtained for Adaptation Same was significantly smaller than for Baseline and Adaptation Opposite. In Experiment 2, it was significantly smaller than for Matched Noise. Adaptation effects were absent for cN1 and cP2 latencies. These findings demonstrate direction-specific adaptation of the motion-onset AEP. This suggests that veridical auditory motion detectors contribute to the motion-onset AEP.

Absence of direction‐specific cross‐modal visual–auditory adaptation in motion‐onset event‐related potentials

“…In analogy to the motion‐AEP literature (Krumbholz et al ., ; Getzmann, ; Getzmann & Lewald, ,b; Grzeschik et al ., , ), the motion‐VEP components P1 (around 100–130 ms), N2 (around 150–200 ms) and P2 (around 230 ms) will be referred to cP1, cN2 and cP2. Figure shows the response topographies for the visual test stimuli in the three adaptation conditions (Scatter, Adaptation Opposite, Adaptation Same).…”

“…In accordance with the relevant literature on motion‐onset AEPs (Krumbholz et al ., ; Getzmann, ; Getzmann & Lewald, ,b; Grzeschik et al ., , ), the analysis described above was conducted on data that were referenced to an average reference. This reference can be confounded depending on the distribution and spatial sampling of the responses (Junghöfer et al ., ).…”

“…In a previously published study, direction‐specific effects were described for motion‐onset AEPs (Grzeschik et al ., ), using virtual moving sound sources (60°/s) generated by head‐related transfer functions. In this auditory unimodal study, cN1 amplitudes at a fronto‐central group electrode were most reduced when adaptation and test stimuli moved in the same direction, suggesting that cN1 reflects veridical auditory motion detection.…”

“…In recent years, multisensory mechanisms of motion perception have received increasing attention by human brain imaging (Lewis & Van Essen, ; Bremmer et al ., ; Baumann & Greenlee, ; Alink et al ., ; Soto‐Faraco & Väljamäe, ), electrophysiological (Stekelenburg & Vroomen, ; Getzmann & Lewald, ) and behavioural studies (Kitagawa & Ichihara, ; Alais & Burr, ; Meyer et al ., ; Jain et al ., ). To focus on temporal features of the underlying neural processes in the auditory modality, auditory evoked potentials (AEPs) to the onset of motion of an initially stationary sound source were used (Ducommun et al ., ; Getzmann & Lewald, ,b; Grzeschik et al ., , ). These studies demonstrated a fronto‐central motion‐onset response complex, comprising a negative component (change‐Negativity, cN1) at around 140 ms and a positive component (change‐Positivity, cP2) at around 230 ms.…”

“…In the present study, a well‐established approach to assess the direction selectivity of motion‐onset visual evoked potentials (VEPs; Bach & Ullrich, ; Hoffmann et al ., , ; Bach & Hoffmann, ; Hoffmann & Bach, ; Maurer & Bach, ; Heinrich et al ., ; Lorteije et al ., ) and AEPs (Grzeschik et al ., ) was adapted to study the influence of visual motion adaptation on auditory motion processing. Applying free‐field auditory and visual motion, the impact of visual motion history on motion‐onset VEPs and motion‐onset AEPs was assessed.…”