Systems Neuroscience Commons^™

An Infrasonic Missing Fundamental Rises At 18.5hz, Christopher D. Lacomba, Steven A. Lloyd, Ryan A. Shanks

Papers and Publications: Interdisciplinary Journal of Undergraduate Research

The Missing Fundamental (MF) phenomenon is an auditory processing artifact which arises from the perception of a harmonically-structured complex sound in the absence of the complex sound’s fundamental frequency (f₀). Constructive interference occurring between constituent waveforms of the harmonic series may elicit a perceptible tone at the f₀’s pitch. A related illusion, known as binaural auditory beats (BAB), may also generate nonexistent perceptible pitches through a shared mechanism. A harmonic series suggesting to an infrasonic f₀ (1/f) noise and broken MF conditions. This data suggests that an infrasonic MF tone is generated, despite the ...

Localization Of Seismic Signals By The Fiddler Crab, Uca Pugilator, Thomas M. Beazley

University of Tennessee Honors Thesis Projects

No abstract provided.

Exploring The Neural Basis Of Top-Down Guided Action In Macaque Monkeys, Jessica M. Phillips

University of Western Ontario - Electronic Thesis and Dissertation Repository

To thoroughly characterize any brain mechanism requires an appropriate animal model for invasive studies. An invaluable model system used toward a comprehension of cognitive neurophysiology is the macaque monkey. It is important to delineate similarities and limitations for this model in relation to the human brain and cognition. In this thesis, we have thus conducted three experiments to investigate putative generalizations between monkeys and humans regarding the neural processes associated with top-down action control in monkeys.

Our daily behaviour is largely comprised of automatic routine actions. The frequent repetition of certain behaviours in response to particular contexts can give rise ...

An Investigation Of The Neural Mechanism By Which The Prefrontal Cortex Facilitates Anti-Saccade Task Performance, Michael J. Koval

Electronic Thesis and Dissertation Repository

Cognitive control enables us to guide our behaviour in an appropriate manner, such as rapid eye movements (saccades) toward a location or object of interest. A well-established test of cognitive control is the anti-saccade task, which instructs subjects to look away from a suddenly-appearing stimulus. The dorsolateral prefrontal cortex (dlPFC) and anterior cingulate cortex (ACC) are part of a cortical saccade control network that influences the superior colliculus (SC), which sends saccade commands to the brainstem saccade generator. To compare and contrast the roles of the dlPFC and ACC in saccade control, the cryoloop method of reversible cryogenic deactivation was ...

Cortical Plasticity And Tinnitus, Michal Chrostowski

Open Access Dissertations and Theses

Tinnitus is an auditory disorder characterized by the perception of a ringing, hissing or buzzing sound with no external stimulus. Because the most common cause of chronic tinnitus is hearing loss, this neurological disorder is becoming increasingly prevalent in our noise-exposed and ageing society. With no cure and a lack of effective treatments, there is a need for a comprehensive understanding of the neural underpinnings of tinnitus. This dissertation outlines the development and validation of a comprehensive theoretical model of cortical correlates of tinnitus that is used to shed light on the development of tinnitus and to propose improvements to ...

On Sensorimotor Function And The Relationship Between Proprioception And Motor Learning, Jeremy D. Wong

Electronic Thesis and Dissertation Repository

Research continues to explore the mechanisms that mediate successful motor control. Behaviourally-relevant modulation of muscle commands is dependent on sensory signals. Proprioception -- the sense of body position -- is one signal likely to be crucial for motor learning. The present thesis explores the relationship between human proprioception and motor learning.

First we investigated changes to sensory function during the adaptation of arm movements to novel forces. Subjects adapted movements in the presence of directional loads over the course of learning. Psychophysical estimates of perceived hand position showed that motor learning resulted in sensed hand position becoming \emph{biased} in the direction ...

Brain Connectivity Studied By Fmri: Homologous Network Organization In The Rat, Monkey, And Human, R. Matthew Hutchison

Electronic Thesis and Dissertation Repository

The mammalian brain is composed of functional networks operating at different spatial and temporal scales — characterized by patterns of interconnections linking sensory, motor, and cognitive systems. Assessment of brain connectivity has revealed that the structure and dynamics of large-scale network organization are altered in multiple disease states suggesting their use as diagnostic or prognostic indicators. Further investigation into the underlying mechanisms, organization, and alteration of large-scale brain networks requires homologous animal models that would allow neurophysiological recordings and experimental manipulations. My current dissertation presents a comprehensive assessment and comparison of rat, macaque, and human brain networks based on evaluation of ...