Saccades adapt to visual and auditory stepping targets and display an asymmetrical pattern of cross-modal transfer

Reactive saccades are rapid eye movements performed toward salient stimuli. Saccadic adaptation maintains the accuracy of visual reactive saccades throughout life and is thought to occur at the motor level of the saccade circuitry. Recently, we revealed that saccadic adaptation also emerges with non-visual, namely tactile targets (Batikh et al. <i>J Neurophysiol</i> 132: 1183-1197, 2024). In addition, such adaptation of tactile saccades transferred partially to nonadapted visual reactive saccades of similar amplitude, compared with a complete visual-to-tactile transfer, suggesting the adaptation occurred upstream of the motor level common to all saccade modalities. Here, we test whether and how saccadic adaptation and transfer occur for auditory saccades. <i>Experiment 1</i> tested the visual-to-auditory transfer of both backward and forward adaptation whereas <i>experiment 2</i> investigated the possibility of adapting auditory saccades and the extent to which such adaptation transfers to visual saccades. <i>Experiment 1</i> revealed a strong visual-to-auditory transfer of both forward and backward adaptations. In <i>experiment 2</i>, stepping the auditory target to another location while the saccade was in flight induced backward adaptation, but could not elicit any significant forward adaptation. Furthermore, we found a partial auditory-to-visual transfer of backward adaptation, in agreement with our previous findings regarding tactile saccades adaptation. This work brings additional insights into our understanding of saccadic adaptation, highlighting the adaptive functional levels of the different saccade modalities.<b>NEW & NOTEWORTHY</b> In this study, we showed that both backward and forward adaptations of visual reactive saccades transfer to nonadapted auditory saccades. Furthermore, we were able to induce a decrease in auditory saccades amplitude when stepping the target sound backward while the saccade was inflight. This indicates that auditory saccades can be subject to adaptive amplitude changes, which, however, are transferred only partially to visual saccades, pointing to the presence of modality-specific adaptation sites.