Local Versus Global Effects of Isoflurane Anesthesia on Visual Processing in the Fly Brain
What characteristics of neural activity distinguish the awake and anesthetized brain? Drugs such as isoflurane abolish behavioral responsiveness in all animals, implying evolutionarily conserved mechanisms. However, it is unclear whether this conservation is reflected at the level of neural activity...
Saved in:
Published in | eNeuro Vol. 3; no. 4; p. ENEURO.0116-16.2016 |
---|---|
Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
United States
Society for Neuroscience
01.07.2016
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | What characteristics of neural activity distinguish the awake and anesthetized brain? Drugs such as isoflurane abolish behavioral responsiveness in all animals, implying evolutionarily conserved mechanisms. However, it is unclear whether this conservation is reflected at the level of neural activity. Studies in humans have shown that anesthesia is characterized by spatially distinct spectral and coherence signatures that have also been implicated in the global impairment of cortical communication. We questioned whether anesthesia has similar effects on global and local neural processing in one of the smallest brains, that of the fruit fly (Drosophila melanogaster). Using a recently developed multielectrode technique, we recorded local field potentials from different areas of the fly brain simultaneously, while manipulating the concentration of isoflurane. Flickering visual stimuli ('frequency tags') allowed us to track evoked responses in the frequency domain and measure the effects of isoflurane throughout the brain. We found that isoflurane reduced power and coherence at the tagging frequency (13 or 17 Hz) in central brain regions. Unexpectedly, isoflurane increased power and coherence at twice the tag frequency (26 or 34 Hz) in the optic lobes of the fly, but only for specific stimulus configurations. By modeling the periodic responses, we show that the increase in power in peripheral areas can be attributed to local neuroanatomy. We further show that the effects on coherence can be explained by impacted signal-to-noise ratios. Together, our results show that general anesthesia has distinct local and global effects on neuronal processing in the fruit fly brain. |
---|---|
Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 N.T. was funded by an Australian Research Council Future Fellowship (FT120100619) and the Discovery Project (Grant DP130100194). B.V.S. was funded by National Health and Medical Research Council Project APP1103923. The authors declare no competing financial interests. Author Contributions: D.C. B.v.S. and N.T. designed research; D.C. and O.H.Z. performed research; D.C. analyzed data; and D.C., B.v.S., and N.T. wrote the paper. |
ISSN: | 2373-2822 2373-2822 |
DOI: | 10.1523/ENEURO.0116-16.2016 |