Background: Dysregulated responses to stress are implicated in disorders of mood, anxiety, and cognition, along with altered functioning in brain regions including the ventromedial (vmPFC) and dorsolateral prefrontal cortices (dlPFC). Pre-clinical studies suggest that GABA, primary inhibitory neurotransmitter in the brain, modulates response to stress. However, the relationship of cortical GABA with perceived stress remains unclear. Thus, we examined this relationship using in vivo measurements of vmPFC and dlPFC GABA.
Methods: 12 women and 7 men, ages 35-61, participated. MR spectroscopy, using STEAM localization at 7 Tesla (TE=20ms, TM=10ms, TR=3000ms), was used to measure GABA levels in the dlPFC and vmPFC. We tested the relationship of GABA levels with measures of perceived stress and anxiety (Perceived Stress Score [PSS], Spielberg State Trait Anxiety Inventory-State [STAI-S]) using Pearson correlations.
Results: We observed a significant negative correlation between dlPFC GABA and PSS (r=-0.62, p=0.018) and a trend towards a negative correlation with vmPFC GABA (r=-0.44, p=0.099). We did not observe a correlation between GABA levels in either region and STAI-S scores (p>0.62).
Conclusions: These preliminary results suggest that cortical GABA levels correlate with perceived stress and support a role for dysregulated GABAergic functioning in neural circuits involved in the perception of stress.