Whitehead, Kimberley;
(2020)
Somatosensory-evoked and state-dependent neural activity during the equivalent of the last trimester of human gestation.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
The human infant cerebral cortex undergoes substantial development during the equivalent of the last trimester of gestation. Here I focus on the maturation of two key cortical functions: the somatosensory and the sleep-wake systems. The developmental milestones of these two functions were investigated by recording electrical brain activity in infants aged between 28 and 43 corrected gestational weeks. In Chapter 1 I summarise current knowledge on the developmental neurophysiology of the mammalian cortex, and in Chapter 2 I describe my methodology. In Chapter 3 I show that contraction of the limb (hand) or respiratory (diaphragm) muscle is associated with feedback somatosensory cortical activity, which comprises immature fast oscillations that decline towards term age. In Chapter 4 I interrogate the maturation of somatosensory functioning further by applying mechanical stimulation to the body surface. The complete cortical response to touching the hand and face emerges before that following foot stimulation, with a gradual involvement of the ipsilateral hemisphere. In Chapter 5 I demonstrate the emergence of state-dependency of spontaneous slow cortical oscillations at full-term. These data show that immediately prior to normal birth, in parallel with a period of rapid structural development of the cortex and its afferents, there is i) a transition in cortical somatosensory encoding from rudimentary responses to hierarchical bi-hemispheric processing, with a rostro-caudal body gradient, and ii) emergence of sleep-wake state-dependent cortical functioning. The results provide converging evidence of a switch point immediately prior to full-term birth, in which brain circuits are primed for an increased and more complex sensorimotor experience that is state-dependent.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Somatosensory-evoked and state-dependent neural activity during the equivalent of the last trimester of human gestation |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences > Neuro, Physiology and Pharmacology |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10098831 |
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