What does the spike of a sensory neuron mean? This is a fundamental question in computational neuroscience. Conventional approaches provide an answer based on correlation between spike pattern and the stimulus that caused it. However, these approaches do not satisfactorily explain how the brain, which does not have direct knowledge of the world or the stimuli, can achieve this task. This thesis frames the problem in terms of a task for a simulated agent and provides a solution based on an approach which regards action as necessary for acquiring the meaning of neural spikes. This approach differs from some others in that it proposes a new criterion called the sensory invariance criterion, which can be used to associate meaning to spike patterns in terms of action sequences the agent generates. This criterion forms the basis of the Sensory Invariance Driven Action (SIDA) framework presented in this thesis. This framework is implemented in a reinforcement learning agent and the results indicate that the agent can successfully learn to associate meaning to the sensor activity in terms of specific actions which reflect the properties of the stimulus. Further behavioral experiments on the agent show that this framework allows the agent to learn the meaning of complex (spatiotemporal) spike patterns. The successful learning exhibited by the agent raises hopes that SIDA can be used to build agents with natural semantics.

What does the spike of a sensory neuron mean? This is a fundamental question in computational neuroscience. Conventional approaches provide an answer based on correlation between spike pattern and the stimulus that caused it. However, these approaches do not satisfactorily explain how the brain, which does not have direct knowledge of the world or the stimuli, can achieve this task. This thesis frames the problem in terms of a task for a simulated agent and provides a solution based on an approach which regards action as necessary for acquiring the meaning of neural spikes. This approach differs from some others in that it proposes a new criterion called the sensory invariance criterion, which can be used to associate meaning to spike patterns in terms of action sequences the agent generates. This criterion forms the basis of the Sensory Invariance Driven Action (SIDA) framework presented in this thesis. This framework is implemented in a reinforcement learning agent and the results indicate that the agent can successfully learn to associate meaning to the sensor activity in terms of specific actions which reflect the properties of the stimulus. Further behavioral experiments on the agent show that this framework allows the agent to learn the meaning of complex (spatiotemporal) spike patterns. The successful learning exhibited by the agent raises hopes that SIDA can be used to build agents with natural semantics.

abstract: Studies in Second Language Acquisition and Neurolinguistics have argued that adult learners when dealing with certain phonological features of L2, such as segmental and suprasegmental ones, face problems of articulatory placement (Esling, 2006; Abercrombie, 1967) and somatosensory stimulation (Guenther, Ghosh, & Tourville, 2006; Waldron, 2010). These studies have argued that adult phonological acquisition is a complex matter that needs to be informed by a specialized sensorimotor theory of speech acquisition. They further suggested that traditional pronunciation pedagogy needs to be enhanced by an approach to learning offering learners fundamental and practical sensorimotor tools to advance the quality of L2 speech acquisition. This foundational study designs a sensorimotor approach to pronunciation pedagogy and tests its effect on the L2 speech of five adult (late) learners of American English. Throughout an eight week classroom experiment, participants from different first language backgrounds received instruction on Articulatory Settings (Honickman, 1964) and the sensorimotor mechanism of speech acquisition (Waldron 2010; Guenther et al., 2006). In addition, they attended five adapted lessons of the Feldenkrais technique (Feldenkrais, 1972) designed to develop sensorimotor awareness of the vocal apparatus and improve the quality of L2 speech movement. I hypothesize that such sensorimotor learning triggers overall positive changes in the way L2 learners deal with speech articulators for L2 and that over time they develop better pronunciation. After approximately eight hours of intervention, analysis of results shows participants’ improvement in speech rate, degree of accentedness, and speaking confidence, but mixed changes in word intelligibility and vowel space area. Albeit not statistically significant (p >.05), these results suggest that such a sensorimotor approach to L2 phonological acquisition warrants further consideration and investigation for use in the L2 classroom. / Dissertation/Thesis / Doctoral Dissertation English 2015