Healthy aging is accompanied by motor inhibition deficits that involve a slower process of stopping a prepotent motor response (i.e., reactive inhibition) rather than a diminished ability to anticipate stopping (i.e., proactive inhibition). Some studies suggest that efficient motor inhibition is related to GABAergic function. Since age-related alterations in the GABA system have also been reported, motor inhibition impairments might be linked to GABAergic alterations in the cortico-subcortical network that mediates motor inhibition. Thirty young human adults (mean age, 23.2 years; age range, 18 –34 years; 14 men) and 29 older human adults (mean age, 67.5 years; age range, 60 –74 years; 13 men) performed a stop-signal task with varying levels of stop-signal probability. GABA + levels were measured with magnetic resonance spectroscopy (MRS) in right inferior frontal cortex, pre-supplementary motor area (pre-SMA), left sensorimotor cortex, bilateral striatum, and occipital cortex. We found that reactive inhibition was worse in older adults compared with young adults, as indicated by longer stop-signal reaction times (SSRTs). No group differences in proactive inhibition were observed as both groups slowed down their response to a similar degree with increasing stop-signal probability. The MRS results showed that tissue-corrected GABA + levels were on average lower in older as compared with young adults. Moreover, older adults with lower GABA + levels in the pre-SMA were slower at stopping (i.e., had longer SSRTs). These findings suggest a role for the GABA system in reactive inhibition deficits.
CITATION STYLE
Hermans, L., Leunissen, I., Pauwels, L., Cuypers, K., Peeters, R., Puts, N. A. J., … Swinnen, S. P. (2018). Brain GABA levels are associated with inhibitory control deficits in older adults. Journal of Neuroscience, 38(36), 7844–7851. https://doi.org/10.1523/JNEUROSCI.0760-18.2018
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