High resolution 3T fMRI in anesthetized monkeys

Palma Pró-Sistiaga, Franck Lamberton, Thomas Boraud, Romaric Saulnier, Alan R. Young, Bernard Bioulac, Christian Gross, Bernard Mazoyer
Journal of Neuroscience Methods. 2012-03-01; 205(1): 86-95
DOI: 10.1016/j.jneumeth.2011.12.023

Read on PubMed

1. J Neurosci Methods. 2012 Mar 30;205(1):86-95. doi:
10.1016/j.jneumeth.2011.12.023. Epub 2012 Jan 2.

High resolution 3T fMRI in anesthetized monkeys.

Pró-Sistiaga P(1), Lamberton F, Boraud T, Saulnier R, Young AR, Bioulac B, Gross
C, Mazoyer B.

Author information:
(1)GIP Cyceron, Campus Jules Horowitz, Bd. Henri Becquerel, 14074 Caen, France.

Although there are numerous 3T MRI research devices all over the world, only a
few functional studies at 3T have been done in anesthetized monkeys. In the past,
anesthetized preparations were reported to be misleading when exploring cortical
brain regions outside the primary sensory areas. Nonetheless, a great improvement
has been achieved in the limited effect of anesthetic agents on the reactivity of
the brain. Here, we re-address the feasibility and potential applications of the
brain oxygen level dependent (BOLD) fMRI signal in Macaca mulatta monkeys that
have been lightly anesthetized with sevoflurane and curarized. The monkeys were
studied with commercially available coils and sequences using a 3T clinical
magnet. We obtained sagittal T1 scout images, gray matter double inversion
recovery, standard gradient echo sequences and gradient echo functional imaging
sequences. Given that fMRI signals are most readily identified in the cerebral
cortices, we optimized Echo Planar Imaging sequences to reproduce significant
changes in the BOLD signal subsequent to a visual stimulation paradigm. Our
results provide a satisfactory signal to noise ratio with a limited standard
deviation range, when compared with studies on alert macaques. We suggest that
the 3T magnet remains a valuable tool to analyze neural pathways in the macaque
brain under light anesthesia and report the use of spatially resolved fMRI in
higher visual areas of anesthetized monkeys. This methodology avoids the need for
time-consuming training of awake monkeys, is stable over many hours, provides
reproducible data and could be applied successfully to future functional studies.

Copyright © 2011 Elsevier B.V. All rights reserved.

DOI: 10.1016/j.jneumeth.2011.12.023
PMID: 22230769 [Indexed for MEDLINE]

Know more about