Mark Cutkosky, Doctoral Dissertation Advisor (AC)
A new open-access platform for measuring and sharing mTBI data.
2021; 11 (1): 7501
Despite numerous research efforts, the precise mechanisms of concussion have yet to be fully uncovered. Clinical studies on high-risk populations, such as contact sports athletes, have become more common and give insight on the link between impact severity and brain injury risk through the use of wearable sensors and neurological testing. However, as the number of institutions operating these studies grows, there is a growing need for a platform to share these data to facilitate our understanding of concussion mechanisms and aid in the development of suitable diagnostic tools. To that end, this paper puts forth two contributions: (1) a centralized, open-access platform for storing and sharing head impact data, in collaboration with the Federal Interagency Traumatic Brain Injury Research informatics system (FITBIR), and (2) a deep learning impact detection algorithm (MiGNet) to differentiate between true head impacts and false positives for the previously biomechanically validated instrumented mouthguard sensor (MiG2.0), all of which easily interfaces with FITBIR. We report 96% accuracy using MiGNet, based on a neural network model, improving on previous work based on Support Vector Machines achieving 91% accuracy, on an out of sample dataset of high school and collegiate football head impacts. The integrated MiG2.0 and FITBIR system serve as a collaborative research tool to be disseminated across multiple institutions towards creating a standardized dataset for furthering the knowledge of concussion biomechanics.
View details for DOI 10.1038/s41598-021-87085-2
View details for PubMedID 33820939
Compensation of physiological motion enables high-yield whole-cell recording in vivo
JOURNAL OF NEUROSCIENCE METHODS
2021; 348: 109008
Whole-cell patch-clamp recording in vivo is the gold-standard method for measuring subthreshold electrophysiology from single cells during behavioural tasks, sensory stimulations, and optogenetic manipulation. However, these recordings require a tight, gigaohm resistance, seal between a glass pipette electrode's aperture and a cell's membrane. These seals are difficult to form, especially in vivo, in part because of a strong dependence on the distance between the pipette aperture and cell membrane.We elucidate and utilize this dependency to develop an autonomous method for placement and synchronization of pipette's tip aperture to the membrane of a nearby, moving neuron, which enables high-yield seal formation and subsequent recordings deep in the brain of the living mouse.This synchronization procedure nearly doubles the reported gigaseal yield in the thalamus (>3 mm below the pial surface) from 26 % (n = 17/64) to 48 % (n = 32/66). Whole-cell recording yield improved from 10 % (n = 9/88) to 24 % (n = 18/76) when motion compensation was used during the gigaseal formation. As an example of its application, we utilized this system to investigate the role of the sensory environment and ventral posterior medial region (VPM) projection synchrony on intracellular dynamics in the barrel cortex.Current methods of in vivo whole-cell patch clamping do not synchronize the position of the pipette to motion of the cell.This method results in substantially greater subcortical whole-cell recording yield than previously reported and thus makes pan-brain whole-cell electrophysiology practical in the living mouse brain.
View details for DOI 10.1016/j.jneumeth.2020.109008
View details for Web of Science ID 000611826600004
View details for PubMedID 33242530
View details for PubMedCentralID PMC7869963
SELECTIVELY COMPLIANT ANNULOPLASTY RING TO ENABLE ANNULAR DYNAMICS IN MITRAL VALVE REPAIR EVALUATED BY IN-VITRO STEREOVISION
AMER SOC MECHANICAL ENGINEERS. 2020
View details for Web of Science ID 000624287000005
Enabling In-Bore MRI-Guided Biopsies With Force Feedback
IEEE TRANSACTIONS ON HAPTICS
2020; 13 (1): 159–66
Limited physical access to target organs of patients inside an MRI scanner is a major obstruction to real-time MRI-guided interventions. Traditional teleoperation technologies are incompatible with the MRI environment and although several solutions have been explored, a versatile system that provides high-fidelity haptic feedback and access deep inside the bore remains a challenge. We present a passive and nearly frictionless MRI-compatible hydraulic teleoperator designed for in-bore liver biopsies. We describe the design components, characterize the system transparency, and evaluate the performance with a user study in a laboratory and a clinical setting. The results demonstrate % difference between input and output forces during realistic manipulation. A user study with participants conducting mock needle biopsy tasks indicates that a remote operator performs equally well when using the device as when holding a biopsy needle directly in hand. Additionally, MRI compatibility tests show no reduction in signal-to-noise ratio in the presence of the device.
View details for DOI 10.1109/TOH.2020.2967375
View details for Web of Science ID 000521334300023
View details for PubMedID 31976906
A Methodology for Individual-Specific Modeling of Rat Optic Nerve Head Biomechanics in Glaucoma
JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME
2018; 140 (8)
Glaucoma is the leading cause of irreversible blindness and involves the death of retinal ganglion cells (RGCs). Although biomechanics likely contributes to axonal injury within the optic nerve head (ONH), leading to RGC death, the pathways by which this occurs are not well understood. While rat models of glaucoma are well-suited for mechanistic studies, the anatomy of the rat ONH is different from the human, and the resulting differences in biomechanics have not been characterized. The aim of this study is to describe a methodology for building individual-specific finite element (FE) models of rat ONHs. This method was used to build three rat ONH FE models and compute the biomechanical environment within these ONHs. Initial results show that rat ONH strains are larger and more asymmetric than those seen in human ONH modeling studies. This method provides a framework for building additional models of normotensive and glaucomatous rat ONHs. Comparing model strain patterns with patterns of cellular response seen in studies using rat glaucoma models will help us to learn more about the link between biomechanics and glaucomatous cell death, which in turn may drive the development of novel therapies for glaucoma.
View details for DOI 10.1115/1.4039998
View details for Web of Science ID 000462361100016
View details for PubMedID 30003249
View details for PubMedCentralID PMC6056184