Characterization of the influence of age on GABA

Gamma-aminobutyric acid (GABA)ergic and glutamatergic neurotransmissions in the prefrontal cortex decreases with age. Further, cognitive function mediated through the dorsolateral prefrontal cortex (DLPFC) also declines with age. Although neuroimaging studies have demonstrated decreased levels of these substances, direct neurophysiological data investigating the effect of aging in the DLPFC in human subjects is lacking. The advent of transcranial magnetic stimulation (TMS) combined with electroencephalography (EEG) has allowed for the assessment of functional neurotransmission in vivo. In the present study, we examined short interval intracortical inhibition (SICI) and intracortical facilitation (ICF) in a group of older adults (> 60 yrs) to evaluate the strength of GABA