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Abu Yosef R, Sultan K, Mobashsher AT, Zare F, Mills PC, Abbosh A. Shielded Cone Coil Array for Non-Invasive Deep Brain Magnetic Stimulation. BIOSENSORS 2024; 14:32. [PMID: 38248409 PMCID: PMC10813362 DOI: 10.3390/bios14010032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/05/2024] [Accepted: 01/08/2024] [Indexed: 01/23/2024]
Abstract
Non-invasive deep brain stimulation using transcranial magnetic stimulation is a promising technique for treating several neurological disorders, such as Alzheimer's and Parkinson's diseases. However, the currently used coils do not demonstrate the required stimulation performance in deep regions of the brain, such as the hippocampus, due to the rapid decay of the field inside the head. This study proposes an array that uses the cone coil method for deep stimulation. This study investigates the impact of magnetic core and shielding on field strength, focality, decay rate, and safety. The coil's size and shape effects on the electric field distribution in deep brain areas are also examined. The finite element method is used to calculate the induced electric field in a realistic human head model. The simulation results indicate that the magnetic core and shielding increase the electric field intensity and enhance focality but do not improve the field decay rate. However, the decay rate can be reduced by increasing the coil size at the expense of focality. By adopting an optimum cone structure, the proposed five-coil array reduces the electric field attenuation rate to reach the stimulation threshold in deep regions while keeping all other regions within safety limits. In vitro and in vivo experimental results using a head phantom and a dead pig's head validate the simulated results and confirm that the proposed design is a reliable and efficient candidate for non-invasive deep brain magnetic stimulation.
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Affiliation(s)
- Rawan Abu Yosef
- The School of Electrical Engineering and Computer Science, The University of Queensland, St. Lucia, QLD 4072, Australia; (R.A.Y.); (F.Z.); (A.A.)
| | - Kamel Sultan
- The School of Electrical Engineering and Computer Science, The University of Queensland, St. Lucia, QLD 4072, Australia; (R.A.Y.); (F.Z.); (A.A.)
| | - Ahmed Toaha Mobashsher
- The School of Electrical Engineering and Computer Science, The University of Queensland, St. Lucia, QLD 4072, Australia; (R.A.Y.); (F.Z.); (A.A.)
| | - Firuz Zare
- The School of Electrical Engineering and Computer Science, The University of Queensland, St. Lucia, QLD 4072, Australia; (R.A.Y.); (F.Z.); (A.A.)
| | - Paul C. Mills
- The School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia;
| | - Amin Abbosh
- The School of Electrical Engineering and Computer Science, The University of Queensland, St. Lucia, QLD 4072, Australia; (R.A.Y.); (F.Z.); (A.A.)
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Lee SW, Fried SI. Micro-magnetic stimulation of primary visual cortex induces focal and sustained activation of secondary visual cortex. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20210019. [PMID: 35658677 DOI: 10.1098/rsta.2021.0019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/01/2021] [Indexed: 06/15/2023]
Abstract
Cortical visual prostheses that aim to restore sight to the blind require the ability to create neural activity in the visual cortex. Electric stimulation delivered via microelectrodes implanted in the primary visual cortex (V1) has been the most common approach, although conventional electrodes may not effectively confine activation to focal regions and thus the acuity they create may be limited. Magnetic stimulation from microcoils confines activation to single cortical columns of V1 and thus may prove to be more effective than conventional microelectrodes, but the ability of microcoils to drive synaptic connections has not been explored. Here, we show that magnetic stimulation of V1 using microcoils induces spatially confined activation in the secondary visual cortex (V2) in mouse brain slices. Single-loop microcoils were fabricated using platinum-iridium flat microwires, and their effectiveness was evaluated using calcium imaging and compared with that of monopolar and bipolar electrodes. Our results show that compared to the electrodes, the microcoils better confined activation to a small region in V1. In addition, they produced more precise and sustained activation in V2. The finding that microcoil-based stimulation propagates to higher visual centres raises the possibility that complex visual perception, e.g. that requiring sustained synaptic inputs, may be achievable. This article is part of the theme issue 'Advanced neurotechnologies: translating innovation for health and well-being'.
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Affiliation(s)
- Seung Woo Lee
- Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Shelley I Fried
- Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Boston VA Healthcare System, Boston, MA, USA
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Lee SM, Lee JE, Lee YK, Yoo DA, Seon DB, Lee DW, Kim CB, Choi H, Lee KH. Thermal-Corrosion-Free Electrode-Integrated Cell Chip for Promotion of Electrically Stimulated Neurite Outgrowth. BIOCHIP JOURNAL 2022. [DOI: 10.1007/s13206-022-00049-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Khalifa A, Zaeimbashi M, Zhou TX, Abrishami SM, Sun N, Park S, Šumarac T, Qu J, Zohar I, Yacoby A, Cash S, Sun NX. The development of microfabricated solenoids with magnetic cores for micromagnetic neural stimulation. MICROSYSTEMS & NANOENGINEERING 2021; 7:91. [PMID: 34786205 PMCID: PMC8589949 DOI: 10.1038/s41378-021-00320-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/16/2021] [Accepted: 10/11/2021] [Indexed: 05/14/2023]
Abstract
Electrical stimulation via invasive microelectrodes is commonly used to treat a wide range of neurological and psychiatric conditions. Despite its remarkable success, the stimulation performance is not sustainable since the electrodes become encapsulated by gliosis due to foreign body reactions. Magnetic stimulation overcomes these limitations by eliminating the need for a metal-electrode contact. Here, we demonstrate a novel microfabricated solenoid inductor (80 µm × 40 µm) with a magnetic core that can activate neuronal tissue. The characterization and proof-of-concept of the device raise the possibility that micromagnetic stimulation solenoids that are small enough to be implanted within the brain may prove to be an effective alternative to existing electrode-based stimulation devices for chronic neural interfacing applications.
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Affiliation(s)
- Adam Khalifa
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA USA
| | - Mohsen Zaeimbashi
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA USA
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA USA
| | - Tony X. Zhou
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA USA
- Department of Physics, Harvard University, Cambridge, MA USA
| | - Seyed Mahdi Abrishami
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA USA
| | - Neville Sun
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA USA
| | - Seunghyun Park
- Department of Physics, Harvard University, Cambridge, MA USA
| | - Tamara Šumarac
- Department of Physics, Harvard University, Cambridge, MA USA
| | - Jason Qu
- Department of Physics, Harvard University, Cambridge, MA USA
| | - Inbar Zohar
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Amir Yacoby
- Department of Physics, Harvard University, Cambridge, MA USA
| | - Sydney Cash
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA USA
| | - Nian X. Sun
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA USA
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