Abstract Optical monitoring of brain activities is intrinsically associated with a range of operational advantages: a. non-ionizing and safe radiation, b. simple and relatively lightweight apparatus, c. readily available commercial optical advanced systems that can be cross adapted for our usage.
DESCRIPTION (provided by applicant): Microscope techniques to image inside brain tissue are generally limited by poor depth penetration. Micro-endoscopy, wherein a probe is physically inserted into the tissue, can overcome this limitation in depth penetration, but at the expense of invasiveness and tissue damage due to the size of the probe. Our goal here is to palliate these problems by developing an ultra-miniature microendoscope probe based on a single, lensless optical fiber.
DESCRIPTION (provided by applicant): There is a great need in clinical neuroscience for improved methods of non-invasively monitoring brain activity. For example, patients with epilepsy often undergo procedures in which electrodes are inserted into their brain to localize the source of seizures. Such invasive procedures carry risk, motivating the need for a non-invasive technique that could detect seizures deep in the brain.
DESCRIPTION (provided by applicant): The goal of this project is fluorescently visualize potassium (K+) egress and extracellular accumulation at the cell surface. The development of this innovative technology has the potential to enable the large-scale spatiotemporal resolution of neuronal and glial cell activity. For this project, we are exploiting the presence of the cell's glycocalyx to attach potassium-sensitive fluorophores exactly where K+ accumulates and is reabsorbed by glia.
DESCRIPTION: Conditionally silencing the activity of specific neural ensembles is a powerful approach for mapping the circuits responsible for specific behaviors. While microbial opsin tools currently exist to silence neural activity with light, these tools have significant limitations tha make them unsuitable for applications that require persistent silencing over the course of minutes or hours.
DESCRIPTION (provided by applicant): Transitioning from small numbers of neural depth recording electrodes to many thousands requires consideration not only of data management, but also how to non-destructively deliver these electrodes into the desired brain regions. Simply developing larger planar probes with more electrodes packed onto the surface invites increased immune response, likelihood of neuronal perturbation due to the presence of the large foreign substrate, and limited spatial sampling distributions.
DESCRIPTION (provided by applicant): In this proposal we leverage our recent developments in MRI acquisition methods and new animal models to attempt direct detection of neuronal currents with Magnetic Resonance Imaging (MRI). If successful, this project will have a high impact for scientific investigations of the nervous system, forming a powerful new tool for human neuroscience by supplementing the commonly applied hemodynamic based MR blood oxygenation level dependent (BOLD) functional MRI (fMRI) technique.
DESCRIPTION There is a great interest in imaging neuronal activity based on changes in fast intrinsic optical signals (e.g. changes in light scattering and phase) that occur on a millisecond timescale. Fast intrinsic optical signals are related to alteration in the complex refractive index and small volume changes near the neuron membrane, in response to the rapid osmotic changes associated with ion fluxes during action potentials.
DESCRIPTION (provided by applicant): Neuroscience has an essential requirement for large-scale neural recording technologies to ensure rapid progress in the understanding of brain function, diagnosis and treatment of neurological disorders. At present, a large gap exists between the localized optical microscopy studies looking at fast neuronal activities at single cell resolution level and the whole-brain observations of slow hemodynamics and brain metabolism provided by the macroscopic imaging modalities.
DESCRIPTION (provided by applicant): Optical imaging holds tremendous promise in our endeavor to understand brain functions. The major challenges for optical brain imaging are depth and speed. Due to strong tissue scattering, the penetration depth and imaging speed of optical microscopy in the mouse brain are very limited. The constraints in depth and speed make large scale, volumetric imaging of mouse brain activity, e.g., functional imaging of an entire mouse cortical column, out of reach of current imaging techniques.
