title: Impedance as a method to sense proximity at the electrode-retina interface.
abstract: Precise positioning of a stimulating electrode in the eye is not possible by simple visualization. However, reliable measurement of responses to retinal stimulation requires consistent positioning. The present study focuses on impedance measurement techniques to sense the proximity of the electrode to the retina. A platinum-iridium stimulation electrode was placed inside the rat eye and impedance was recorded at different positions of the stimulating electrode relative to the retina. The presence of robust electrically evoked response in the superior colliculus indicates that the electrode may not have to be in absolute contact in order to elicit a neural response. Optical coherence tomography imaging confirmed the distance-impedance relationship.
authors: Department of Biomedical Engineering, University of Southern California, Los Angeles, 90033, USA. aditiray@gmail.com
authors: Aditi
authors: A
authors: Ray
authors: Leanne Lai-Hang
authors: LL
authors: Chan
authors: Alejandra
authors: A
authors: Gonzalez
authors: Mark S
authors: MS
authors: Humayun
authors: James D
authors: JD
authors: Weiland
mesh_terms: D000758:Anesthesia; D000818:Animals; D017097:Electric Impedance; D004558:Electric Stimulation; D004566:Electrodes; D019736:Prostheses and Implants; D051381:Rats; D012160:Retina / Q000033:anatomy & histology / Q000502:physiology*; D013238:Stereotaxic Techniques; D013477:Superior Colliculi / Q000502:physiology; D041623:Tomography, Optical Coherence