Date of Award


Degree Type


Degree Name

Master of Science


Developmental Biology


Dr. Bryan S. Richardson

Second Advisor

Dr. Stanley Leung

Third Advisor

Dr. Douglas Fraser


The development of electrocortical (ECoG) activity in humans and other mammals have been shown to be well-correlated with the neuroanatomical development of the brain, suggesting that ECoG activity may provide a functional role in brain development. Studies of ECoG state activity in utero, primarily in sheep, and of behavioural/sleep states in human newborns indicate that these states undergo maturational changes and are altered with hypoxic insults and adverse pregnancy conditions, such as fetal growth restriction. The purpose of the present study was firstly to design an automated computer analysis to comprehensively and objectively characterize ECoG activity, thereby providing a framework from which to study maturational events and effects of chronic hypoxemia. Using automated analysis, normo×ic ovine fetuses showed maturational changes in multiple aspects of ECoG activity comparable to those previously reported using visual analysis techniques. In addition, maturational changes were observed in transition times, with the mean duration of transitions from low-voltage/high frequency to high-voltage/low frequency state epochs (TLH) increasing with advancing gestation, providing insight into the development of control circuitries responsible for sleep state patterns. Chronic fetal hypoxemia induced by placental embolizations resulted in alterations in ECoG maturational events, with an early decrease in low-voltage/high frequency (LV∕HF) state epochs likely reflecting an adaptive response, while a prolongation in state transition times with advancing gestation may indicate possible aberrant control circuitry development which could have long-term implications for central nervous system function.



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