The role of neurometabolites in human behavior and learning

Understanding the neurophysiological mechanisms that drive human behavior has been a long-standing focus of neuroscience. One well-known neuro-metabolite involved in the creation of optimal behavioral repertoires is GABA, the main inhibitory neurotransmitter in the human brain. In humans, one increasingly used in vivo approach to measuring GABA levels is Magnetic Resonance Spectroscopy (MRS). MRS-assessed GABA levels have been associated with various types of behavior, for example, perceptual acuity, motor response performance and executive function. Furthermore, expanding abilities and enhancing skills through short-term learning have been reported to depend on the modulation of GABA levels in task-related brain areas. Across larger time scales (up to lifetime development), age-related changes/differences in brain GABA levels have been implicated in the decline of various behaviors, such as inhibitory control and other higher cognitive functions. However, the implications of MRS measures of GABA for behavior remain poorly understood and it is yet to be determined how GABA levels within distinct task-related brain regions of interest account for differences in behavioral performance. Therefore, we carried out the following studies to further investigate the role of MRS-assessed GABA in human performance and learning.