Multimodal longitudinal imaging to monitor neurovascular responses to brain injuries
| dc.contributor.advisor | Luan, Lan | en_US |
| dc.creator | Sun, Yingchu | en_US |
| dc.date.accessioned | 2024-05-20T19:18:01Z | en_US |
| dc.date.created | 2024-05 | en_US |
| dc.date.issued | 2024-02-05 | en_US |
| dc.date.submitted | May 2024 | en_US |
| dc.date.updated | 2024-05-20T19:18:01Z | en_US |
| dc.description | EMBARGO NOTE: This item is embargoed until 2026-05-01 | en_US |
| dc.description.abstract | The evolution of brain injury comprises diverse dynamic interactions between initial triggers of injury and evolutionarily conserved responses of brain plasticity, remodeling, and compensation. Altered neurovascular activity is critical endogenous responses to various brain injuries, which not only underlies the evolution of cascades of neuroinflammation and cell death but also simultaneously pave the way for recovery. Owing to the multifaceted nature of neurovascular interactions, simultaneously monitoring of neurons, vasculature, and other cells and neurotransmitters through these evolving events are necessary to provide comprehensive understanding of the impairment and recovery. Here we employ a multimodal platform that integrate various imaging techniques and electrophysiology to reveal the lasting, dynamic changes of neurovascular activity following two types of brain injuries: the intracortical implantation of a ultraflexible polymer electrode, and high-energy-density, short-pulsed microwave radiation. By integrating multiple imaging methods such as two-photon imaging, laser speckle contrast imaging and intrinsic optical imaging, we were able to bridge spatial resolution from sub-cellular to regional and detect alterations in multiple biomarkers including cerebral blood flow, microvasculature, and extracellular glutamate. In the first study, we find heightened angiogenesis and vascular remodeling in the first two weeks after implantation of flexible electrodes, which coincides with the rapid increase in local field potentials and unit activities detected by electrophysiological recordings. Vascular remodeling in shallow cortical layers preceded that in deeper layers, which often lasted longer than the recovery of neural signals. In the second study, we find that microwave radiation led to a suppression of glutamate release, which aligns with the decrease in local field potentials. Conversely, we noted a rise in cerebral blood flow during the stimulation. Although it seems that heating may contribute partially to this observed increase, it's essential to acknowledge that other mechanisms, such as the thermoelastic stress waves, have substantial impact as well. It is supported by the fact that pulsed microwave radiation affected cerebral blood flow differently compared to continuous microwave radiation. The deeper study also reveals that the focused ultrasound stimulation does not affect the glutamate release, neural activities and cerebral blood flow. Taking together, my study has effectively tracked both vascular remodeling and neural recovery following the ultraflexible neural electrode implantation over several weeks. And we also identified biological responses within seconds of the brain receiving microwave radiation and focused ultrasound stimulation. These efforts have paved the way for future interventions for neurovascular injuries and recovery. | en_US |
| dc.embargo.lift | 2026-05-01 | en_US |
| dc.embargo.terms | 2026-05-01 | en_US |
| dc.format.mimetype | application/pdf | en_US |
| dc.identifier.citation | Sun, Yingchu. Multimodal longitudinal imaging to monitor neurovascular responses to brain injuries. (2024). Masters thesis, Rice University. https://hdl.handle.net/1911/115902 | en_US |
| dc.identifier.uri | https://hdl.handle.net/1911/115902 | en_US |
| dc.language.iso | eng | en_US |
| dc.rights | Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder. | en_US |
| dc.subject | Imaging techniques | en_US |
| dc.subject | neurovascular response | en_US |
| dc.subject | brain injuries | en_US |
| dc.title | Multimodal longitudinal imaging to monitor neurovascular responses to brain injuries | en_US |
| dc.type | Thesis | en_US |
| dc.type.material | Text | en_US |
| thesis.degree.department | Electrical and Computer Engineering | en_US |
| thesis.degree.discipline | Engineering | en_US |
| thesis.degree.grantor | Rice University | en_US |
| thesis.degree.level | Masters | en_US |
| thesis.degree.name | Master of Science | en_US |