AUTHOR=Kondo Hirohito M. , Oba Takeyuki , Ezaki Takahiro , Kochiyama Takanori , Shimada Yasuhiro , Ohira Hideki 

TITLE=Striatal GABA levels correlate with risk sensitivity in monetary loss

JOURNAL=Frontiers in Neuroscience

VOLUME=18

YEAR=2024

URL=https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2024.1439656

DOI=10.3389/fnins.2024.1439656

ISSN=1662-453X

ABSTRACT=<sec id="sec1001"><title>Background</title><p>Decision-making under risk is a common challenge. It is known that risk-taking behavior varies between contexts of reward and punishment, yet the mechanisms underlying this asymmetry in risk sensitivity remain unclear.</p></sec><sec id="sec2001"><title>Methods</title><p>This study used a monetary task to investigate neurochemical mechanisms and brain dynamics underpinning risk sensitivity. Twenty-eight participants engaged in a task requiring selection of visual stimuli to maximize monetary gains and minimize monetary losses. We modeled participant trial-and-error processes using reinforcement learning.</p></sec><sec id="sec3001"><title>Results</title><p>Participants with higher subjective utility parameters showed risk preference in the gain domain (<italic>r</italic> = −0.59) and risk avoidance in the loss domain (<italic>r</italic> = −0.77). Magnetic resonance spectroscopy (MRS) revealed that risk avoidance in the loss domain was associated with γ-aminobutyric acid (GABA) levels in the ventral striatum (<italic>r</italic> = −0.42), but not in the insula (<italic>r</italic> = −0.15). Using functional magnetic resonance imaging (fMRI), we tested whether risk-sensitive brain dynamics contribute to participant risky choices. Energy landscape analyses demonstrated that higher switching rates between brain states, including the striatum and insula, were correlated with risk avoidance in the loss domain (<italic>r</italic> = −0.59), a relationship not observed in the gain domain (<italic>r</italic> = −0.02).</p></sec><sec id="sec4001"><title>Conclusions</title><p>These findings from MRS and fMRI suggest that distinct mechanisms are involved in gain/loss decision making, mediated by subcortical neurometabolite levels and brain dynamic transitions.</p></sec>