Resting GABA and glutamate concentrations do not predict visual gamma frequency or amplitude
Cousijn H., Haegens S., Wallis G., Near J., Stokes MG., Harrison PJ., Nobre AC.
SignificanceIn vitro and modeling studies have indicated that GABAergic signaling underlies gamma oscillations. It would be valuable to measure this correlation between GABA and gamma oscillations in the human brain, and a recent study [Muthukumaraswamy SD, et al. (2009)Proc Natl Acad Sci USA106(20):8356–8361] indicated that this is possible, using magnetoencephalography and magnetic resonance spectroscopy. If true, such a correlation would make the gamma peak frequency a useful surrogate marker of cortical excitability for studies investigating clinical populations and/or the effects of pharmacological agents. However, magnetic resonance spectroscopy does not measure synaptic GABA specifically, and the results from the current study (n= 50) indicate that GABA, as measured with magnetic resonance spectroscopy, does not correlate with gamma peak frequency.