Poster D89, Monday, March 26, 8:00-10:00 am, Exhibit Hall C
Norepinephrine signals functional resetting: Evidence from human pupil dilation to pattern changes
Sijia Zhao1, Shigeto Furukawa2, Hsin-I Liao2, Frederic Dick3, Maria Chait1; 1Ear Institute, University College London, UK, 2NTT Communication Science Laboratories, NTT Corporation, Japan, 3Birkbeck-UCL Centre for Neuroimaging, London, UK
The statistics of natural scenes are highly dynamic, leading to constantly changing patterns of sensory input. Current theories suggest that perception is guided by internal models that continuously track the statistics of the unfolding sensory scene. Norepinephrine (NE) is assumed to play an important role in this process by reporting unexpected uncertainty (Yu and Dayan, 2005) and initiating functional resetting (Dayan and Yu, 2006; Sara and Bouret, 2012). However, most previous studies have used slowly-changing stimulus patterns and active-decision tasks, thus making it difficult to tease apart evidence accumulation from associated decision processes. To address this problem, we indexed NE release using pupillometry (Joshi et al, 2016) and used very rapidly changing stimuli to tap putatively 'pre-attentive' evidence accumulation. Human participants listened to sequences of abutting 50ms-tone-pips which contained transitions from randomly to regularly repeating frequency patterns and vice versa. To make sure participants attended to the auditory stream but not to the transition per se, they were instructed to detect occasional silent gaps within the sequence. This task encouraged attentive listening but was independent of sequence regularity. Despite the fact that both regular-to-random and random-to-regular transitions are clearly detectable behaviorally and evoke strong MEG (Barascud et al., 2016) and EEG (Southwell et al., 2016) responses, pupil-dilation responses were only evoked by transitions from regular to random sequences (unexpected uncertainty) and NOT by the emergence of pattern (precision increase). These results suggest that NE release may be involved in 'resetting' the brain’s internal model of the ongoing sensory environment.
Topic Area: PERCEPTION & ACTION: Audition