Cristin G. Welle - US grants

Project Summary To further our understanding of the function of neural circuits, there is a need for new tools that can collect simultaneous measurements from large populations of neurons involved in a common neural computation and provide precise functional modulation. Optical imaging in awake animals expressing calcium indicators provides real-time functional and spatial information from individual neurons within local neural circuits. The limitations of current imaging technology include small fields of view encompassing single brain regions, and the requirement for head fixation, which prevents naturalistic behavior. In addition, most optical imaging systems do not allow for simultaneous high-resolution functional imaging in combination with spatially-localized optogenetic modulation. To meet this challenge, we propose to develop an optical device (`3D-FAST') that allows for rapid, real-time volumetric neural recording and precise optical stimulation. By pairing miniature arrays of micropatterned LED emitters with the axial focusing capabilities of electrowetting lens technologies, we will achieve duplex recording and stimulation of many thousands of neurons. Through utilization of novel 3D-printed scaffolding, we will be able to create modular, expandable, customizable lens arrays that allow for recording of large-scale bi-directional neural interfaces for closed-loop modulation of neural circuits. We will create the 3D-FAST device through assembly of modular optical elements in a 3D-printed scaffolding. The initial device will be tested in in the anesthetized mouse during the presentation of visual stimuli. Optogenetic stimulation will be used to bias circuit function. In sum, these experiments will demonstrate the unique capabilities of the 3D-FAST technology. Rapid, high- resolution imaging of calcium transients from a volume of tissue will be paired with spatially-restricted light delivery for optogenetic neural modulation. The optical imaging properties will be compared with ground-truth two-photon microscopy, and the functional consequence of neuromodulation will be dissected through circuit modulation. The 3D-FAST tool will bring novel capabilities to measuring and modulating large populations of neurons in animals, to better understand the neural computations that underlie behavior. In addition, this body of work will lay the ground for future development of fully implantable optical recording and modulating units for use in freely-moving, untethered naturalistic behavior experiments.

PROJECT SUMMARY AND ABSTRACT Existing neurotechnologies continue to make significant clinical impact, but challenges remain for scientists and engineers in moving new devices from the bench to the bedside. This grant will support the development of a comprehensive educational training program on the best practices for successfully navigating the translational and commercialization pathway for neural medical devices. The educational program will include (1) a series of publicly available video lectures that will be assembled and curated into a certificate program by a diverse group of program faculty with significant experience in moving neurotechnologies from the bench to the bedside. These short-course video lectures will cover the following topics: preclinical model systems, safety and efficacy studies, good laboratory practices, device testing, quality system processes, regulatory agency interactions, steps in developing an investigational device exemption (IDE) application, reimbursement agency interactions, clinical trial design with an emphasis on quantitative outcome measures of target engagement, bioethical considerations that are specific to neural medical devices, techniques for securing strong intellectual property claims, funding opportunities available for technology development and clinical trials, and advice on moving neurotechnology into successful commercial ventures. In addition, the educational program will provide (2) an annual three-day workshop in which participants will work with program faculty to think through and develop submissions to an institutional review board (IRB), the FDA, and/or funding groups for their own devices or devices inspired by relevant case studies. The workshop will be open to academic researchers, clinician scientists, and small-business entrepreneurs who are interested in gaining expertise that will help them translate their own neural medical devices. Participants of the workshop will be encouraged to continue interacting with program faculty through regular online follow-ups. The hands-on workshop will be offered for two years during the grant funding period with the goal of extending the workshop in future years through collaborations with our ongoing relationships with neural interfaces conferences.

Nearly 1 million people in the United States alone are affected by Multiple Sclerosis (MS). MS is an inflammatory, demyelinating disease of the central nervous system (CNS). While MS is classically regarded as a disease of the white matter, the number of white matter lesions does not correlate with physical disability or cognitive impairment. Recent evidence indicates that gray matter areas have significant myelin loss and increased cortical lesion load is associated with increased cortical atrophy and cognitive decline. Functional imaging of patients with MS reveals increased hyperexcitability within primary motor cortex and throughout the motor network. Moreover, functional recovery in MS patients is associated with normalization of aberrant cortical activity, suggesting a relationship between motor network hyperexcitability and impaired motor behavior. However, our understanding of how myelin loss influences the activity of single neurons, or neural circuits, within grey matter is extremely limited. Outstanding questions such as, what are the consequences of demyelination on neural physiology in the intact CNS, how demyelinating injuries affect the acquisition of new skills, and can therapies that can enhance remyelination can restore neural and behavioral function remain unknown. Recently, we have developed new approaches to visualize myelin, oligodendrocytes, and their precursors in the intact mouse brain, as well as longitudinal approaches to record and monitor neural activity in behaving animals. We have also identified novel behavioral interventions that enhance myelin repair. In this application, we propose to capitalize on the dynamics revealed by these techniques to discern the effects of myelin loss and repair on local circuit activity and motor behavior. The objectives of this proposal are: 1) evaluate how myelin loss affects neuronal circuit function and 2) to elucidate the effectiveness of remyelination therapies on restoring neural function and behavior. This proposal will demonstrate the effects of demyelination on cortical neuronal and circuit function in vivo. These studies will validate an in vivo mouse model platform to test efficacy of new therapeutic candidates for MS, and provide clinically relevant data regarding the efficacy of therapies that stimulate endogenous remyelination in MS on restoring neural and behavioral function.

Project Summary To further our understanding of the function of neural circuits, there is a need for new tools that can collect simultaneous measurements from large populations of neurons involved in a common neural computation and provide precise functional modulation. Optical imaging in awake animals expressing calcium or voltage indicators provides real-time functional and spatial information from individual neurons within local neural circuits. The limitations of current imaging technology include small fields of view encompassing single brain regions, and the requirement for head fixation, which prevents naturalistic behavior. In addition, most optical imaging systems do not allow for simultaneous high- resolution functional imaging in combination with spatially-localized optogenetic modulation. To meet this challenge, we propose to develop an optical device (`3D-FAST') that allows for rapid, real- time volumetric neural recording and precise optical stimulation. By pairing miniature arrays of micropatterned LED emitters with the axial focusing capabilities of electrowetting lens technologies, we will achieve duplex recording and stimulation of many thousands of neurons. Through utilization of novel 3D-printed scaffolding, we will be able to create modular, expandable, customizable lens arrays that allow for recording of large-scale bi-directional neural interfaces for closed-loop modulation of neural circuits. We will create two versions of the 3D-FAST device. 3D-FAST-GECI that will provide fast, volumetric imaging at 30 Hz for GCaMP imaging, and 3D-FAST-GEVI that will provide frame rates of 1 kHz at a single plane combined with a slower, high resolution volume scan. Initially, the devices will be tested in the anesthetized, and then awake, freely moving mouse for experiments using GCaMP, voltage indicators ASAP and Voltron, and finally combining with localized optogenetics for closed loop feedback. In sum, these experiments will demonstrate the unique capabilities of the 3D-FAST technology. Rapid, imaging of improved voltage indicators will be paired with spatially-restricted light delivery for optogenetic neural modulation for the first time in a freely moving mouse. The optical imaging properties will be compared with ground-truth two-photon microscopy, and the functional consequence of neuromodulation will be dissected through behavioral assays. The 3D-FAST tool will bring novel capabilities to measuring and modulating large populations of neurons in freely-moving animals, to better understand the neural computations that underlie behavior. In addition, this body of work will lay the ground for future development of fully implantable optical recording and modulating units for use in freely-moving, untethered naturalistic behavior experiments.