title: Custom-designed high-density conformal planar multielectrode arrays for brain slice electrophysiology.
abstract: Multielectrode arrays have enabled electrophysiological experiments exploring spatio-temporal dynamics previously unattainable with single electrode recordings. The finite number of electrodes in planar MEAs (pMEAs), however, imposes a trade-off between the spatial resolution and the recording area. This limitation was circumvented in this paper through the custom design of experiment-specific tissue-conformal high-density pMEAs (cMEAs). Four configurations were presented as examples of cMEAs designed for specific stimulation and recording experiments in acute hippocampal slices. These cMEAs conformed in designs to the slice cytoarchitecture whereas their high-density provided high spatial resolution for selective stimulation of afferent pathways and current source density (CSD) analysis. The cMEAs have 50 or 60 microm center-to-center inter-electrode distances and were manufactured on glass substrates by photolithographically defining ITO leads, insulating them with silicon nitride and SU-8 2000 epoxy-based photoresist and coating the etched electrode tips with gold or platinum. The ability of these cMEAs to stimulate and record electrophysiological activity was demonstrated by recording monosynaptic, disynaptic, and trisynaptic field potentials. The conformal designs also facilitated the selection of the optimal electrode locations for stimulation of specific afferent pathways (Schaffer collaterals; medial versus lateral perforant path) and recording the corresponding responses. In addition, the high-density of the arrays enabled CSD analysis of laminar profiles obtained through sequential stimulation along the CA1 pyramidal tree.
authors.affiliation: Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089-1451, USA. gholmieh@usc.edu
authors.forename: Ghassan
authors.initials: G
authors.lastname: Gholmieh
authors.forename: Walid
authors.initials: W
authors.lastname: Soussou
authors.forename: Martin
authors.initials: M
authors.lastname: Han
authors.forename: Ashish
authors.initials: A
authors.lastname: Ahuja
authors.forename: Min-Chi
authors.initials: MC
authors.lastname: Hsiao
authors.forename: Dong
authors.initials: D
authors.lastname: Song
authors.forename: Armand R
authors.initials: AR
authors.lastname: Tanguay
authors.forename: Theodore W
authors.initials: TW
authors.lastname: Berger
mesh_terms: D000344:Afferent Pathways / Q000166:cytology / Q000502:physiology; D000465:Algorithms; D000818:Animals; D001921:Brain / Q000502:physiology*; D017352:Echo-Planar Imaging / Q000295:instrumentation* / Q000379:methods; D004558:Electric Stimulation; D004594:Electrophysiology; D006624:Hippocampus / Q000166:cytology / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D008839:Microelectrodes; D036103:Nanotechnology; D011712:Pyramidal Tracts / Q000166:cytology / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012023:Reflex, Monosynaptic / Q000502:physiology; D013569:Synapses / Q000502:physiology