Medicine and Health Sciences Commons^™

Mechanisms Of Sensory Adaptation In The Primate Visual System, Boris Isaac Peñaloza Rojas

Electronic Theses and Dissertations

Under ecological conditions, the luminance impinging on the retina varies within a dynamic range of 220 dB. Stimulus contrast can also vary drastically within a scene, and eye movements leave little time for sampling luminance. In addition, the amount of information reaching our visual system far exceeds the brain’s information processing capacity. Given the limited dynamic range of its neurons and its limited capacity in processing visual information in real-time, the brain deploys both structural and functional solutions that work in tandem to adapt to the surroundings. In this work, employing visual psychophysics and computational neuroscience, we study the mechanisms …

Studying Facial Expression Recognition And Imitation Ability Of Children With Autism Spectrum Disorder In Interaction With A Social Robot, Farzaneh Askari

Electronic Theses and Dissertations

Children with Autism Spectrum Disorder (ASD) experience limited abilities in recognizing non-verbal elements of social interactions such as facial expressions [1]. They also show deficiencies in imitating facial expressions in social situations. In this Master thesis, we focus on studying the ability of children with ASD in recognizing facial expressions and imitating the expressions using a rear-projected expressive humanoid robot, called Ryan. Recent studies show that social robots such as Ryan have great potential for autism therapy. We designed and developed three studies, first to evaluate the ability of children with ASD in recognizing facial expressions that are presented to …

Modeling Hrtf For Sound Localization In Normal Listeners And Bilateral Cochlear Implant Users, Douglas A. Miller

Electronic Theses and Dissertations

Mathematical models can be very useful for understanding complicated systems and for testing algorithms through simulation that would be difficult or expensive to implement. This dissertation presents a model that attempts to simulate the sound localization performance of persons using bilateral cochlear implants. The expectation is that this model could prove to be a useful tool in developing new signal processing algorithms for neural encoding strategies.

The head related transfer function (HRTF) is a critical component of this model, and in the ideal case, provides the base characteristics of head shadow, torso and pinna effects. This defines the temporal, intensity …

A Model For Electrical Communication Between Cochlear Implants And The Brain, Douglas A. Miller

Electronic Theses and Dissertations

In the last thirty years, cochlear implants have become an invaluable instrument in the treatment of severe-to-profound hearing impairment. An important aspect of research in the continued development of cochlear implants is the in vivo assessment of signal processing algorithms intended to improve perception of speech and other auditory signals. In trying to determine how closely cochlear implant recipients process sound relative to the processing done by a normal auditory system, various assessment techniques have been applied. The most common technique has been measurement of auditory evoked potentials (AEPs), which involves the recording of neural responses to auditory stimulation. Depending …