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  • Kathrin Weidacker
    Swansea University
  • Stephen J Johnston
    Swansea University
  • Paul G. Mullins
  • Frederic Boy
    Swansea University
  • Simon Dymond
    Swansea University
Background
Neurobehavioral research on the role of impulsivity in gambling disorder (GD) has produced heterogeneous findings. Impulsivity is multifaceted with different experimental tasks measuring different subprocesses, such as response inhibition and distractor interference. Little is known about the neurochemistry of inhibition and interference in GD.

Methods
We investigated inhibition with the stop signal task (SST) and interference with the Eriksen Flanker task, and related performance to metabolite levels in individuals with and without GD. We employed magnetic resonance spectroscopy (MRS) to record glutamate–glutamine (Glx/Cr) and inhibitory, γ-aminobutyric acid (GABA+/Cr) levels in the dorsal ACC (dACC), right dorsolateral prefrontal cortex (dlPFC), and an occipital control voxel.

Results
We found slower processing of complex stimuli in the Flanker task in GD (P < .001, η2p = 0.78), and no group differences in SST performance. Levels of dACC Glx/Cr and frequency of incongruent errors were correlated positively in GD only (r = 0.92, P = .001). Larger positive correlations were found for those with GD between dACC GABA+/Cr and SST Go error response times (z = 2.83, P = .004), as well as between dACC Glx/Cr and frequency of Go errors (z = 2.23, P = .03), indicating general Glx-related error processing deficits. Both groups expressed equivalent positive correlations between posterror slowing and Glx/Cr in the right dlPFC (GD: r = 0.74, P = .02; non-GD: r = .71, P = .01).

Conclusion
Inhibition and interference impairments are reflected in dACC baseline metabolite levels and error processing deficits in GD.

Keywords

  • GABA, Gambling, MRS, response inhibition, response interference
Original languageEnglish
Pages (from-to)475-485
Number of pages11
JournalCNS Spectrums
Volume27
Issue number4
Early online date23 Mar 2021
DOIs
Publication statusPublished - Aug 2022

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