A neural hierarchy for illusions of time: Duration adaptation precedes multisensory integration

Abstract

Perceived time is inherently malleable. For example, adaptation to relatively long or short sensory events leads to a repulsive aftereffect such that subsequent events appear to be contracted or expanded (duration adaptation). Perceived visual duration can also be distorted via concurrent presentation of discrepant auditory durations (multisensory integration). The neural loci of both distortions remain unknown. In the current study we use a psychophysical approach to establish their relative positioning within the sensory processing hierarchy. We show that audiovisual integration induces marked distortions of perceived visual duration. We proceed to use these distorted durations as visual adapting stimuli yet find subsequent visual duration aftereffects to be consistent with physical rather than perceived visual duration. Conversely, the concurrent presentation of adapted auditory durations with nonadapted visual durations results in multisensory integration patterns consistent with perceived, rather than physical, auditory duration. These results demonstrate that recent sensory history modifies human duration perception prior to the combination of temporal information across sensory modalities and provides support for adaptation mechanisms mediated by duration selective neurons situated in early areas of the visual and auditory nervous system (Aubie, Sayegh, & Faure, 2012; Duysens, Schaafsma, & Orban, 1996; Leary, Edwards, & Rose, 2008).

An investigation of the spatial selectivity of the duration after-effect

“…We observed a clear duration after-effect, corroborating the findings by Heron and colleagues (Heron et al, 2012(Heron et al, , 2013. More importantly, the effect of adaptation was present at each of the measured distances and did not decrease for larger adapter-test distances.…”

“…To address this issue we investigated the spatial selectivity of the duration after-effect by parametrically varying the distance between adapter and test stimuli in two experiments. In both experiments we observed a duration after-effect, replicating the pattern of repulsion following duration adaptation demonstrated in earlier studies (Heron et al, 2012(Heron et al, , 2013Li, Yuan, & Huang, 2015). Furthermore, the duration aftereffect occurred at all measured distances, with no evidence for a decrease in the magnitude of the after-effect at larger distances.…”

“…Reading out the relative activation of groups of these neurons would allow for an explicit representation of duration that can be used for further processing. The observation that the duration after-effect does not transfer across modalities suggests that duration information is encoded separately for each modality, and combined later on during processing to form a more complete, multimodal representation of duration (Heron, Hotchkiss, Aaen-Stockdale, Roach, & Whitaker, 2013;Heron et al, 2012;Van Wassenhove, 2009).…”

“…A relevant question that is currently being investigated is that of the relative position of these duration-selective channels along the visual processing hierarchy (Hayashi et al, 2015;Heron et al, 2013;Li, Yuan, & Huang, 2015). It has been proposed that duration-selective neurons are present in early sensory areas for both auditory and visual information (Heron et al, 2012).…”

“…We adopted the paradigm introduced by Heron et al (2012Heron et al ( , 2013 and adapted participants to visual stimuli of varying duration. Following adaptation, participants completed a cross-modal duration judgment task comparing an auditory reference to a visual test stimulus.…”