Real-time Optical Neuroimaging

Open Access
Author:
Masteller, Andrew M
Area of Honors:
Biomedical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Patrick James Drew, Thesis Supervisor
  • William O Hancock, Honors Advisor
  • Nanyin Zhang, Faculty Reader
Keywords:
  • optical neuroimaging
  • hemodynamics
  • cerebral blood volume
  • intrinsic signal optical imaging
Abstract:
Precise and accurate detection of localized neural activity in the mouse brain requires the use of extracellular electrode recordings. In order to properly implant the electrodes, the surgeon must rely on general anatomical features that can differ between subjects. Inappropriately placed recording electrodes can damage the neural tissue, altering the physiology being studied. Improved methods for detecting the functional regions of interest are needed for future studies of neural responses. Intrinsic-signal optical imaging is an established technique for conveying neural activity through coupled hemodynamic responses of localized neurovasculature. The mouse brain can be imaged through a thinned-skull window with targeted incident light. Changes in total cerebral blood volume were measured with 530nm green incident light, providing equal absorbance of oxygenated and deoxygenated hemoglobin. A customized software solution was developed to control image acquisition, external stimulation, and image processing. Post-stimulus raw data were compared to baseline readings to give percent change in absorption as an effective method to identify regions of increased neural activity while providing real-time results to the surgeon. The user interface was developed to allow for simple control of the testing parameters without requiring knowledge of the coding system. By setting the stimulation parameters of the system to correlate with the study at hand, the surgeon can visualize where to properly implant the electrodes for each subject of independent studies.