Selectivity of neural stimulation in the auditory system: a comparison of optic and electric stimuli.
Pulsed, mid-infrared lasers were recently investigated as a method to stimulate neural activity. There are significant benefits of optically stimulating nerves over electrically stimulating, in particular the application of more spatially confined neural stimulation. We report results from experiments in which the gerbil auditory system was stimulated by optical radiation, acoustic tones, or electric current. Immunohistochemical staining for the protein c-FOS revealed the spread of excitation. We demonstrate a spatially selective activation of neurons using a laser; only neurons in the direct optical path are stimulated. This pattern of c-FOS labeling is in contrast to that after electrical stimulation. Electrical stimulation leads to a large, more spatially extended population of labeled, activated neurons. In the auditory system, optical stimulation of nerves could have a significant impact on the performance of cochlear implants, which can be limited by the electric current spread.
Izzo
Agnella D
AD
Northwestern University, Biomedical Engineering, 2145 Sheridan Road, Tech E310, Evanston, Illinois 60208, USA.
Suh
Eul
E
Pathria
Jyoti
J
Walsh
Joseph T
JT
Whitlon
Donna S
DS
Richter
Claus-Peter
CP
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005849:Gerbillinae; D010775:Photic Stimulation / Q000379:methods*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013136:Spiral Ganglion / Q000502:physiology*
D016760:Proto-Oncogene Proteins c-fos