Serum testosterone and electroencephalography spectra in developmental male rhesus Macaca mulatta monkeys

The main objectives in this work were to determine whether the relationship between serum testosterone concentration and electroencephalography (EEG) develop mental change observed in human males is also present in Macaca mulatta and, if so, to determine which frequency bands are involved and which regions change in pre-pubertal monkeys as a function of serum testosterone concentration. Nine healthy monkeys were divided into three groups according to age. Serum testosterone was measured using immunoenzymatic chemiluminescent assay. EEG results were processed using Fast Fourier transform; average relative spectral power analysis was calculated and separated into delta and theta bands. The main findings were higher delta relative power in temporal area of the youngest group. Significant positive correlations were observed between serum testosterone levels and theta relative power across the entire scalp, and between theta relative power at frontal and temporal locations and in negative direction between delta relative power in temporal areas. Partial correlations controlling for cephalic perimeter remained significant between testosterone and total theta relative power and theta relative power in temporal areas. Partial correlations remained significant for theta relative power controlling for age at temporal locations. Our data show that testosterone may be a significant covariate in EEG development in Macaca mulatta males.