Global Field Power and Averaging in Measuring Somatosensory Evoked Potentials under Anesthesia

2009 ◽  
pp. 1724-1727
Author(s):  
A. Joutsen ◽  
L. -P. Lyytikäinen ◽  
O. Pajulo ◽  
A. Etelämäki ◽  
V. Jäntti ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Somatosensory Evoked Potentials ◽  
Global Field ◽  
Global Field Power

scholarly journals Global field power helps separate respiratory-related evoked potentials from EMG contamination

2000 ◽  
Vol 88 (1) ◽  
pp. 282-290 ◽  
Author(s):  
J. Andrew Daubenspeck ◽  
Lisa M. Lim ◽  
Metin Akay
Keyword(s):  
Evoked Potentials ◽  
Pressure Pulse ◽  
Applied Pressure ◽  
Global Field ◽  
Rectangular Grid ◽  
Global Field Power ◽  
Oral Pressure ◽  
Afferent Information ◽  
The Mean ◽  
The Right

Respiratory-related evoked potentials (RREPs) were stimulated by brief (200-ms) oral pressure pulses (−10 cmH2O) applied at the onset of inspiration in 12 subjects. Scalp potentials were measured at 30 sites on a rectangular grid that encompassed the right side of the scalp overlying the somatosensory cortex (SSC). Concurrent and significant masseter EMG (mEMG) activity was evoked by the pressure pulse, and we found correlational evidence for contamination of the RREP by the mEMG. The global field power (GFP) was used to provide a robust, reference-independent measure of SSC activation that provided partial insulation from mEMG contamination. The mean GFP from all subjects, reflective of afferent information from respiratory mechanoreceptors, showed a latency to onset of significant afferent SSC activity of ∼25 ms. Scalp GFP activity during control experiments (absence of applied pressure) was significant and may reflect ongoing afferent activity from inspiration.

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