title: A thin film polyimide mesh microelectrode for chronic epidural electrocorticography recording with enhanced contactability.
abstract: OBJECTIVE
  Epidural electrocorticography (ECoG) activity may be more reliable and stable than single-unit-activity or local field potential. Invasive brain computer interface (BCI) devices are limited by mechanical mismatching and cellular reactive responses due to differences in the elastic modulus and the motion of stiff electrodes. We propose a mesh-shaped electrode to enhance the contactability between surface of dura and electrode.
  
  
  METHODS
  We designed a polyimide (PI) electrode with a mesh pattern for more conformal contact with a curved surface. We compared the contact capability of mesh PI electrodes with conventionally used sheet PI electrode. The electrical properties of the mesh PI electrode were evaluated for four weeks. We recorded the epidural ECoG (eECoG) activity on the surface of rhesus monkey brains while they performed a saccadic task for four months.
  
  
  RESULTS
  The mesh PI electrode showed good contact with the agarose brain surface, as evaluated by visual inspection and signal measurement. It was about 87% accurate in predicting the direction of saccade eye movement.
  
  
  CONCLUSIONS
  Our results indicate that the mesh PI electrode was flexible and good contact on the curved surface and can record eECoG activity maintaining close contact to dura, which was proved by in vivo and in vitro test.
authors.affiliation: School of Bio-convergence Engineering, College of Health Science, Korea University, Seoul, Republic of Korea. Department of Biomedical Engineering, College of Health Science, Korea University, Seoul, Republic of Korea.
authors.forename: Dong-Hyun
authors.initials: DH
authors.lastname: Baek
authors.forename: Jeyeon
authors.initials: J
authors.lastname: Lee
authors.forename: Hang Jin
authors.initials: HJ
authors.lastname: Byeon
authors.forename: Hoseok
authors.initials: H
authors.lastname: Choi
authors.forename: In
authors.initials: I
authors.lastname: Young Kim
authors.forename: Kyoung-Min
authors.initials: KM
authors.lastname: Lee
authors.forename: James
authors.initials: J
authors.lastname: Jungho Pak
authors.forename: Dong
authors.initials: D
authors.lastname: Pyo Jang
authors.forename: Sang-Hoon
authors.initials: SH
authors.lastname: Lee
mesh_terms: D000818:Animals; D001921:Brain / Q000502:physiology; D062207:Brain-Computer Interfaces; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000295:instrumentation* / Q000379:methods*; D004824:Epidural Space / Q000502:physiology*; D007094:Imides; D008253:Macaca mulatta; D008297:Male; D008839:Microelectrodes; D008953:Models, Anatomic; D058117:Neural Prostheses; D011108:Polymers; D011597:Psychomotor Performance / Q000502:physiology; D012438:Saccades / Q000502:physiology; D013526:Surgical Mesh
chemical_list: D007094:Imides; D011108:Polymers