Biology subjects

Liao, H.-I.

Publications and source records attributed to Liao, H.-I..

4 recordsLinked to original sources

bioRxiv2020

Impact of conscious awareness on pupillary response to faces

Pupillary response reflects not only ambient light changes but also top-down factors. Nevertheless, it remains inconclusive whether the conscious awareness modulates the pupillary response. We investigated pupillary responses to faces under different conscious conditions using continuous flash suppression (CFS). In Experiment 1 and 2, we used a breaking-CFS procedure in which participants had to detect the face from suppression. Results showed that the pupil constricted more to upright faces than to inverted faces before the face was detected, suggesting that pupillary responses reflect face processing entering consciousness. In Experiment 3 and 4, we used a fixed duration-CFS procedure with both objective performance and subjective reports. Different pupillary responses were observed only when the participant was aware of the face. These findings imply that the conscious awareness is critical for modulating autonomic neural circuits of the pupillary function. The corresponding pupillary responses may reflect dynamic processes underlying conscious awareness.

neuroscience↗

bioRxiv2020

Transient Pupil Constriction Reflects and Affects Facial Attractiveness

Contrary to the long-held belief of a close linkage between pupil dilation and attractiveness, we found an early and transient pupil constriction response when participants viewed an attractive face (and the effect of luminance/contrast is controlled). While human participants were making an attractiveness judgment on faces, their pupil constricted more for the more attractive (as-to-be-rated) faces. Further experiments showed that the effect of pupil constriction to attractiveness judgment extended to intrinsically aesthetic visual objects such as natural scene images (as well as faces) but not to line-drawing geometric figures. When participants were asked to judge the roundness of faces, pupil constriction still correlated with their attractiveness but not the roundness rating score, indicating the automaticity of the pupil constriction to attractiveness. When pupillary responses were manipulated implicitly by relative background luminance changes (from the pre-stimulus screen), the facial attractiveness ratings were in accordance with the amount of pupil constriction, which could not be explained solely by simultaneous or sequential luminance contrast. The overall results suggest that pupil constriction not only reflects but, as a part of self-monitoring and attribution mechanisms, also possibly contributes facial attractiveness implicitly.

neuroscience↗

bioRxiv2019

Deep, soft, and dark sounds induce autonomous sensory meridian response

There has been a growing interest in the autonomous sensory meridian response (ASMR). The ASMR is characterized by a tingling sensation around the scalp and neck and often induces a feeling of relaxation and a reduction of a negative mood. However, it is still unknown what factors affect the ASMR. The present study focused on stimulus characteristics and individuals mood states and personality traits. Participants filled out self-reported questionnaires (the Profile of Mood States, Beck Depression Inventory, and Big Five Inventory) and reported ASMR estimates throughout a 17-min experiment while listening to binaural tapping and brushing sounds. Cross-correlation results showed that the ASMR estimates were strongly associated with the acoustic features of auditory stimuli, such as their amplitude, spectral centroid, and spectral bandwidth. This indicates that low-pitched sounds with dark timbre trigger the ASMR. The maximum ASMR was observed around 2 s after the acoustic features changed, suggesting that the sluggishness of multisensory integration may lead to the ASMR experience. In addition, individual differences in the ASMR experience were closely linked to participants mood states, such as anxiety, but not to their personality traits. Our results provide important clues to understand the mechanisms of auditory-somatosensory interactions. Significant StatementsThe autonomous sensory meridian response (ASMR) is characterized by a tingling, electrostatic-like sensation across the scalp and back of the neck. This phenomenon can be triggered by a variety of audiovisual stimuli, and many people seek out the ASMR via the internet to receive a feeling of relaxation and reduce a negative mood. We show that the ASMR is induced about 2 s after acoustic features, such as the amplitude, spectral centroid, and spectral bandwidth are changed. This suggests that low-pitched sounds with dark timbre lead to the ASMR experience. The stimulus-driven ASMR effect is found regardless of the personality traits or mood states of participants. Our findings provide a critical clue to understand the mechanisms of auditory-somatosensory interactions.

neuroscience↗

bioRxiv2018

Phasic norepinephrine is a neural interrupt signal for unexpected events in rapidly unfolding sensory sequences - evidence from pupillometry

The ability to track the statistics of our surroundings is a key computational challenge. A prominent theory (Dayan & Yu, 2006) proposes that the brain monitors for unexpected uncertainty - events which deviate substantially from model predictions, indicating model failure. Norepinephrine (NE) is thought to play a key role in this process by serving as an interrupt signal, initiating model-resetting. However, evidence is from paradigms where participants actively monitored stimulus statistics. To determine whether NE routinely reports the statistical structure of our surroundings, even when not behaviourally relevant, we used rapid tone-pip sequences that contained perceptually salient pattern-changes associated with abrupt structural violations vs. emergence of regular structure. Phasic pupil dilations (PDR) were monitored to assess NE. We reveal a remarkable specificity: When not behaviourally relevant, only abrupt structural violations evoked a PDR. The results demonstrate that NE tracks unexpected uncertainty on rapid time scales relevant to sensory signals.

neuroscience↗