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Head turning is a common sound localization strategy in primates. A novel system that can track head movement and acoustic signals received at the entrance to the ear canal was tested to obtain binaural sound localization information during fast head movement of marmoset monkey. Analysis of binaural information was conducted

Head turning is a common sound localization strategy in primates. A novel system that can track head movement and acoustic signals received at the entrance to the ear canal was tested to obtain binaural sound localization information during fast head movement of marmoset monkey. Analysis of binaural information was conducted with a focus on inter-aural level difference (ILD) and inter-aural time difference (ITD) at various head positions over time. The results showed that during fast head turns, the ITDs showed significant and clear changes in trajectory in response to low frequency stimuli. However, significant phase ambiguity occurred at frequencies greater than 2 kHz. Analysis of ITD and ILD information with animal vocalization as the stimulus was also tested. The results indicated that ILDs may provide more information in understanding the dynamics of head movement in response to animal vocalizations in the environment. The primary significance of this experimentation is the successful implementation of a system capable of simultaneously recording head movement and acoustic signals at the ear canals. The collected data provides insight into the usefulness of ITD and ILD as binaural cues during head movement.
ContributorsLabban, Kyle John (Author) / Zhou, Yi (Thesis director) / Buneo, Christopher (Committee member) / Dorman, Michael (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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Description
Head movement is a natural orienting behavior for sensing environmental events around us. Head movement is particularly important for identifying through the sense of hearing the location of an out-of-sight, rear-approaching target to avoid danger or threat. This research aims to design a portable device for detecting the head movement

Head movement is a natural orienting behavior for sensing environmental events around us. Head movement is particularly important for identifying through the sense of hearing the location of an out-of-sight, rear-approaching target to avoid danger or threat. This research aims to design a portable device for detecting the head movement patterns of common marmoset monkeys in laboratory environments. Marmoset is a new-world primate species and has become increasingly popular for neuroscience research. Understanding the unique patterns of their head movements will improve its values as a new primate model for uncovering the neurobiology of natural orienting behavior. Due to their relatively small head size (5 cm in diameter) and body weight (300-500 g), the device has to meet several unique design requirements with respect to accuracy and workability. A head-mount wireless tracking system was implemented based on inertial sensors that are capable of detecting motion in the Yaw, Pitch and Roll axes. The sensors were connected to the encoding station, which transmits wirelessly the 3-axis movement data to the decoding station at the sampling rate of ~175 Hz. The decoding station relays this information to the computer for real-time display and analysis. Different tracking systems, based on the accelerometer and Inertial Measurement Unit is implemented to track the head movement pattern of the marmoset head. Using these systems, translational and rotational information of head movement are collected, and the data analysis focuses on the rotational head movement in body-constrained marmosets. Three stimulus conditions were tested: 1) Alert, 2) Idle 3) Sound only. The head movement patterns were examined when the house light was turned on and off for each stimulus. Angular velocity, angular displacement and angular acceleration were analyzed in all three axes.

Fast and large head turns were observed in the Yaw axis in response to the alert stimuli and not much in the idle and sound-only stimulus conditions. Contrasting changes in speed and range of head movement were found between light-on and light-off situations. The mean peak angular displacement was 95 degrees (light on) and 55 (light off) and the mean peak angular velocity was 650 degrees/ second (light on) and 400 degrees/second (light off), respectively, in response to the alert stimuli. These results suggest that the marmoset monkeys may engage in different modes of orienting behaviors with respect to the availability of visual cues and thus the necessity of head movement. This study provides a useful tool for future studies in understanding the interplay among visual, auditory and vestibular systems during nature behavior.
ContributorsPandey, Swarnima (Author) / Zhou, Yi (Thesis advisor) / Tillery, Stephen H (Thesis advisor) / Buneo, Christpher A (Committee member) / Arizona State University (Publisher)
Created2015