Transcranial photo-inactivation of neural activities in the mouse auditory cortex.
Flavoprotein fluorescence in the brain is intimately coupled with neuronal aerobic energy metabolism. If flavoproteins are photobleached, neural activities may be affected owing to dysfunction in aerobic energy metabolism in mitochondria. We tested this possibility in cortical slices from mice, and found that exposure to blue light (lambda = 475 nm) derived from a 20 mW diode laser for 50 min suppresses trans-synaptic components of field potentials. This finding formed the basis of a transcranial photo-inactivation technique, that was used to investigate auditory signal transmission between the anterior auditory field (AAF) and the primary auditory cortex (AI) in anesthetized mice. Cortical responses in AAF and AI, elicited by 5 kHz tonal stimuli, were visualized using transcranial flavoprotein fluorescence imaging. After determining responsive areas in AAF and AI, the auditory cortex was exposed to the blue diode laser via the intact skull, while either AAF or AI was protected with a piece of carbon paper. Although the photo-inactivation of AI had no significant effect on the fluorescence responses in AAF, the photo-inactivation of AAF significantly reduced the fluorescence responses in AI, indicating the presence of auditory signal transmission from AAF to AI.
Kubota
Yamato
Y
Department of Neurophysiology, Brain Research Institute, Niigata University, Asahi-machi, Chuo-ku, Niigata 951-8585, Japan.
Kamatani
Daiki
D
Tsukano
Hiroaki
H
Ohshima
Shinsuke
S
Takahashi
Kuniyuki
K
Hishida
Ryuichi
R
Kudoh
Masaharu
M
Takahashi
Sugata
S
Shibuki
Katsuei
K
D000818:Animals; D001303:Auditory Cortex / Q000166:cytology* / Q000502:physiology*; D001931:Brain Mapping; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D005071:Evoked Potentials / Q000528:radiation effects; D005260:Female; D005420:Flavoproteins / Q000378:metabolism; D005453:Fluorescence; D005947:Glucose / Q000494:pharmacology; D066298:In Vitro Techniques; D008027:Light; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D018709:Statistics, Nonparametric
D005420:Flavoproteins; D005947:Glucose