Oculomotor inhibition precedes temporally expected auditory targets

Abstract

Eye movements are inhibited prior to the onset of temporally-predictable visual targets. This oculomotor inhibition effect could be considered a marker for the formation of temporal expectations and the allocation of temporal attention in the visual domain. Here we show that eye movements are also inhibited before predictable auditory targets. In two experiments, we manipulate the period between a cue and an auditory target to be either predictable or unpredictable. The findings show that although there is no perceptual gain from avoiding gaze-shifts in this procedure, saccades and blinks are inhibited prior to predictable relative to unpredictable auditory targets. These findings show that oculomotor inhibition occurs prior to auditory targets. This link between auditory expectation and oculomotor behavior reveals a multimodal perception action coupling, which has a central role in temporal expectations.

Fig. 1. Experimental procedure of Experiment 1.

a After an online gaze contingent procedure confirmed fixation (<0.5° off center) and following an additional random inter-trial-interval (ITI; 0.4–0.9 s), the temporal cue (pure tone of 5 KHz) was played for 33 ms, marking the onset of the foreperiod (1/1.5/2/2.5/3 s). After the foreperiod, the target tone (descending or ascending chirp sound) was played for 33 ms and participants were asked to perform a 2-alternative forced choice (2AFC) discrimination task: report whether the chirp was ascending or descending by pressing one of two buttons. Participants were instructed to be as accurate as possible and to respond within the 4 seconds response window. Following the response, or after 4 s without one, the fixation cross changed color to gray for 200 ms to signal the end of the trial. b The foreperiod was either constant throughout the block (predictable condition) or changed randomly in different trials within the same block (unpredictable condition). Thus, the cue acted as a 100% valid temporal cue in the predictable condition but was uninformative regarding target timing in the unpredictable condition. The stimuli were identical in the two conditions, and differed only in the validity of the temporal cue in predicting the time of the target. Participants were not informed as to any predictability; therefore, all temporal expectations were learned incidentally.

Fig. 2. Accuracy-rates and reaction times (RTs) by predictability and foreperiod.

a Accuracy-rates in predictable (pink bars) and unpredictable (turquoise bars) conditions. N = 20 participants. b Reaction times in predictable (pink bars) and unpredictable (turquoise bars) conditions. Error bars denote ±1 standard error of the mean, corrected for within-subjects variability. N = 20 participants. Source data are provided as a Source Data file.

Fig. 3. Saccade rates by predictability and foreperiod.

Grand average (N = 20) saccade rate traces in the predictable (pink) and unpredictable (turquoise) conditions in each foreperiod duration. The dark gray horizontal rectangle represents the foreperiod duration. The dashed line represents target onset. The light gray shading represents the analyzed interval. Source data are provided as a Source Data file.

Fig. 4. Pretarget saccade rates by predictability and foreperiod.

a Grand average pretarget saccade rate in the predictable (pink) and unpredictable (turquoise) conditions at −100 to 0 ms relative to target onset. N = 20 participants.; b Saccade rate slope assessed by calculating the normalized difference between saccade rate in the interval 400–500 ms following cue onset and saccade rate in the interval −100 to 0 ms relative to target onset at 0. This difference value was then divided by the time in seconds between the two intervals. Error bars denote ±1 standard error of the mean, corrected for within-subjects variability. N = 20 participants. Source data are provided as a Source Data file.

Fig. 5. Blink rates by predictability and foreperiod.

a Grand average (N = 20) blink rate traces in the predictable (pink) and unpredictable (turquoise) conditions in each foreperiod duration, smoothed with a sliding window of 100 ms. The light gray rectangles mark the analysis window. The dashed line represents target onset. b Grand average pretarget blink rate in the predictable (pink bars) and unpredictable (turquoise bars) conditions at −500 to 0 ms relative to target onset. Error bars denote ±1 standard error of the mean, corrected for within-subjects variability. N = 20 participants. Source data are provided as a Source Data file.

Fig. 6. Saccade rates according to trial performance.

a Grand average saccade rates in correct trials (green) and incorrect trials (blue) of the unpredictable condition. The dashed line represents target onset. The gray rectangle marks the pre-stimulus analysis window. b Grand average saccade rates in fast trials (green) and slow trials (blue) of the unpredictable condition, divided according to the median. Source data are provided as a Source Data file.

Fig. 7. Experiment 2: Accuracy-rates and reaction times (RTs) in the 1 second foreperiod.

a Accuracy-rates in predictable (pink bars) and unpredictable (turquoise bars) conditions. N = 20 participants. b Reaction times in predictable (pink bars) and unpredictable (turquoise bars) conditions. Error bars denote ±1 standard error of the mean, corrected for within-subjects variability. The colored connecting lines represents individual participants. N = 20 participants. Source data are provided as a Source Data file.

Fig. 8. Experiment 2: Saccade rates and blink rates.

a Grand average saccade rate traces in the 80% predictable (pink) and the unpredictable (turquoise) conditions. The gray rectangle marks the 900–1000 ms post-cue analysis window. The black line represents cue offset. The bar graph to the right depicts the calculated saccade rate average within the analysis window. N = 20 participants. b Grand average of the blink rates traces in the 80% predictable (pink) and the unpredictable (turquoise) conditions. The gray rectangle marks the 500–1000 ms post-cue analysis window. The black line represents cue offset. The bar graph to the right represents the calculated blink rate average within the analysis window. Error bars denote ±1 standard error of the mean, corrected for within-subjects variability. The colored connecting lines represent individual participants. N = 20 participants. Source data are provided as a Source Data file.