A5100671074- Neuroscience and Neural Engineering
- EEG and Brain-Computer Interfaces
- Advanced Memory and Neural Computing
- Photoreceptor and optogenetics research
- Transcranial Magnetic Stimulation Studies
- Neural dynamics and brain function
- Retinal Development and Disorders
- Neurological disorders and treatments
- Retinal and Macular Surgery
- Advanced Sensor and Energy Harvesting Materials
- Autism Spectrum Disorder Research
- Family and Disability Support Research
- Analytical Chemistry and Sensors
- Optical Imaging and Spectroscopy Techniques
- Axon Guidance and Neuronal Signaling
- 3D Printing in Biomedical Research
- 3D IC and TSV technologies
- Functional Brain Connectivity Studies
- Wireless Power Transfer Systems
- Child Development and Digital Technology
- Conducting polymers and applications
- Cultural and Historical Studies
- Nanoporous metals and alloys
- Molecular Communication and Nanonetworks
- Mental Health and Well-being
Massachusetts General Hospital
2014-2023
Harvard University
2014-2023
Ajou University
2022-2023
VA Boston Healthcare System
2012-2016
Seoul National University
2011
Electrical stimulation is currently used to treat a wide range of cardiovascular, sensory and neurological diseases. Despite its success, there are significant limitations application, including incompatibility with magnetic resonance imaging, limited control electric fields decreased performance associated tissue inflammation. Magnetic overcomes these but existing devices (that is, transcranial stimulation) large, reducing their translation chronic applications. In addition, not effective...
Magnetic stimulation from cortically implantable microcoils can activate neuronal circuits with high selectivity and reliability.
Flexible polymers have gained much attention in the development of low cost, magnetic resonance compatible, and nonfragile implantable medical devices. However, efficacy conventional polymer encapsulations containing hybrid interfaces is limited due to their relatively high moisture absorption unstable interfacial adhesion aqueous environments. As an alternative, we report on a monolithic encapsulation platform for neuroprosthetic devices using liquid crystal (LCPs), which very degree...
The enhanced electrochemical activity of nanostructured materials is readily exploited in energy devices, but their utility scalable and human-compatible implantable neural interfaces can significantly advance the performance clinical research electrodes. We utilize low-temperature selective dealloying to develop biocompatible one-dimensional platinum nanorod (PtNR) arrays that exhibit superb properties at various length scales, stability, biocompatibility for high neurotechnologies. PtNR...
Wireless neural stimulators are being developed to address problems associated with traditional lead-based implants. However, designing wireless on the sub-millimeter scale (<1mm3) is challenging. As device size shrinks, it becomes difficult deliver sufficient power operate device. Here, we present a sub-millimeter, inductively powered stimulator consisting only of coil receive power, capacitor tune resonant frequency receiver, and diode rectify radio-frequency signal produce excitation. By...
Magnetic stimulation is less sensitive to the inflammatory reactions that plague conventional electrode-based cortical implants and therefore may be useful as a next-generation (implanted) prosthetic. The fields arising from micro-coils are quite small however thus, their ability modulate activity must first established. Here, we show layer V pyramidal neurons (PNs) can strongly activated by micro-coil further, asymmetric such coils do not simultaneously activate horizontally-oriented axon...
The purpose of our study is to evaluate the biocompatibility various polymers used as microelectrode arrays (MEAs) in retinal prostheses through vitro cytotoxicity testing following a standardizedThree types polymer-based MEAs were examined: silicone-based platinum, polyimide-based gold and liquid crystal polymer (LCP)-based MEAs. silicone/platinum fabricated by Nd:YAG laser, polyimide/gold semiconductor manufacturing technique, LCP/gold laser micromachining thermal-bonding process. All...
Despite ongoing advances in our understanding of local single-cellular and network-level activity neuronal populations the human brain, extraordinarily little is known about their "intermediate" microscale circuit dynamics. Here, we utilized ultra-high-density microelectrode arrays a rare opportunity to perform intracranial recordings across multiple cortical areas participants discover three distinct classes that are not locked natural brain rhythmic activity. The first included fast...
In working to improve the quality of visual percepts elicited by retinal prosthetics, considerable effort has been made understand how neurons respond electric stimulation. Whereas responses arising from direct activation ganglion cells have well studied, through indirect (e.g., secondary bipolar cells) are not as understood. Here, we used cell-attached, patch-clamp recordings measure rabbit in vitro a wide range stimulus-pulse parameters (amplitudes: 0-100 μA; durations: 0.1-50 ms), applied...
BackgroundAutism spectrum disorder (ASD) is characterised by abnormalities in social interactions and restricted repetitive behaviors. Children with high-functioning ASD (HFASD), lack communication skills, do not interact others, peer relationships. We aimed to develop, evaluate the feasibility of, a metaverse-based programme enhance skills of children HFASD.MethodsThis open-label, single-centre, pilot parallel randomised controlled trial (RCT) was conducted on boys aged 7–12 years HFASD....
Electrical stimulation via cortically implanted electrodes has been proposed to treat a wide range of neurological disorders. Effectiveness limited, however, in part due the inability conventional activate specific types neurons while avoiding other types. Recent demonstrations that magnetic from micro-coil can selectively pyramidal (PNs) passing axons suggest possibility such an approach overcome some this limitation and here we use computer simulations explore how design influences...
Neurons carry electrical signals and communicate via activities. The therapeutic potential of stimulation (ES) for the nervous system, including retina, through improvement cell survival function has been noted. Here we investigated neuroprotective regenerative ES in a mouse model inherited retinal degeneration.Rhodopsin-deficient (Rho-/-) mice received one or two sessions transpalpebral sham treatments 7 consecutive days. Intraperitoneal injection 5-ethynyl-2'-deoxyuridine was used to label...
Micro-coil magnetic stimulation of brain tissue presents new challenges for MEMS micro-coil probe fabrication. The main are threefold; (i) low coil resistance high power efficiency, (ii) leak current from the into in vitro experimental set-up, (iii) adaptive process technology because dynamic research area, which requires agile design changes. Taking on these challenges, we present a fabrication that has three features; multilayer resist lift-off to pattern up 1800-nm-thick metal films, and...
The ciliary epithelium (CE) of adult mammals has been reported to provide a source retinal stem cells (RSCs) that can give rise all cell types in vitro. A recent study, however, suggests CE-derived possess properties pigmented epithelial and display little neurogenic potential. Here we show the potential is negatively regulated by ephrin-A3, which upregulated CE postnatal mice presents strong prohibitory niche for RSCs. Addition ephrin-A3 inhibits proliferation RSCs increases pigment 349...
Magnetic stimulation delivered via 0.5-mm diameter coils was recently shown to activate retinal neurons; the small coil size raises possibility that micromagnetic ( μMS) could underlie a new generation of implanted neural prosthetics. Such an approach has several inherent advantages over conventional electric stimulation, including potential for selective activation neuronal targets as well less susceptibility inflammatory responses. The viability μMS some applications, e.g., deep brain...
To adopt micropatterning technology in manufacturing silicone elastomer-based microelectrode arrays for retinal stimulation, a silicone-polyimide hybrid array was proposed and tested vivo.Gold microelectrodes were created by semiconductor based on polyimide hybridized with elastomer spin coating. The stability of the between two materials flex blister tested. feasibility electrode evaluated rabbit eye reviewing optical coherence tomography (OCT) findings after suprachoroidal implantation.The...
Electrical stimulation via microelectrodes implanted in cortex has been suggested as a potential treatment for wide range of neurological disorders. Despite some success however, the effectiveness conventional electrodes remains limited, part due to an inability create specific patterns neural activity around each electrode and challenges with maintaining stable interface. The use implantable micro-coils magnetically stimulate overcome these limitations because asymmetric fields from coils...
Magnetic stimulation of the nervous system, e.g. transcranial magnetic (TMS), has been used both to unravel basic structure and function system as well treat neurological diseases, i.e. clinical depression. Despite progress in areas, ongoing advancements have limited by a lack understanding mechanism which alters neural activity. Here, we report responses cortical neurons arising from sub-millimeter coil. Cell attached patch clamp was record activity layer 5/6 pyramidal prefrontal cortex...
Cortical visual prostheses that aim to restore sight the blind require ability create neural activity in cortex. Electric stimulation delivered via microelectrodes implanted primary cortex (V1) has been most common approach, although conventional electrodes may not effectively confine activation focal regions and thus acuity they be limited. Magnetic from microcoils confines single cortical columns of V1 prove more effective than microelectrodes, but drive synaptic connections explored....
In this research, inductive telemetric structure for retinal prosthesis was developed based on Liquid Crystal Polymers. For power and data transmission into the polymer-based implant which is conformable to eye surface, designed coil thermo-formed convex shape. The geometric parameters of were optimized using finite element method (FEM) simulations maximizing coupling coefficient quality factor. electrical properties fabricated coils characterized their performance tested. deformed compared...
Transcranial magnetic stimulation (TMS) is a noninvasive method that modulates neural activity in the central nervous systems. It has been widely used both to study basic structure and function of system as well treat neurological diseases, i.e. clinical depression. However, ongoing advancements have hampered by lack understanding mechanisms which TMS activity. Here, we report responses from two distinct types cortical pyramidal neurons arising sub-millimeter coil. Cell attached patch clamps...
Cortical neural prostheses that aim to restore useful vision, hearing, and tactile sensations require the ability selectively target different cortical regions simultaneously. Electrical stimulation via intracortical electrodes has been used create spatial patterns of activation. However, their efficacy remains limited due inability conventional confine activation specific around each electrode. Magnetic from single bent wires can activate pyramidal neurons while avoiding passing axons,...
Recently micro-magnetic stimulation (μMS) with sub-millimeter coils has been successfully used to stimulate retinal neurons in vitro. This raises the possibility that such could be a wide range of neural prosthetics, as they may provide safer alternative direct electrical stimulation. However, ability μMS modulate neuronal activity brain not studied. Here we show strongly modulates subthalamic nucleus (STN) Cell attached patch clamp was record response both pulsatile and sinusoidal...
Magnetic stimulation using micro-coils has shown to be an effective method for brain neural modulation [1]. These could arguably superior commonly used micro-electrodes in terms of long-term functionality. This is because, unlike electrode based devices, magnetic coils do not need have direct contact with tissues and thus their efficiency capability degrade overtime. In this study, we compare three different show that the use magnetic-core inductors substantially improve coil's performance...