Table 4:
Glutamate and GABA and cognition in mood disorders
| Author | N (HC/BD/MDD) | Diagnosis | Mood Status | Illness stage | Medication status | Cognitive domain | Region | Tesla | Metabolite | Acquisition | Sequence | TE (ms) | Reference | Metabolite level group difference | Associations between metabolites and cognition |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| (Dickstein et al., 2008) | 48/36 | Mood dys-regulation | NR | NR | Off meds | WASI | frontal lobe, hippocampus, POC, and parietal lobe | 1.5 | Glx | SV | PRESS | 30 | Cr | - | No associations |
| (Wozniak et al., 2012) | 13/24 | Mood dys-regulation | NR | NR | Mixed | WASI | ACC | 4 | Glu | SV | PRESS | 30 | W | ↑Glu | No associations |
| (Jayaweera et al., 2015) | 21/0/35 | MDD | Depressed | Chronic | Mixed | WTAR, MMSE, RAVLT | Left hippocampus | 3 | Glu | SV | PRESS | 35 | Cr | - | Lower levels of hippocampal Glu are associated with poor memory retention in HC, but not MDD |
| (Hermens et al., 2015) | 40/75/ 90 | BD and MDD | Recently Depressed | Chronic | Mixed | WTAR, RAVLT,TMT | Left hippocampus | 3 | Glu | SV | PRESS | 35 | Cr | ↑Glu | No associations |
| (Shirayama et al., 2017) | 27/0/22 | MDD | Depressed | FE | naïve | TMT, RAVLT, Verbal paired associates test, Stroop, VF | MPFC, right hippocampus and amygdala | 3 | Glu, Gln, Glx | SV | PRESS | 30 | Cr | ↓Glu in the MPFC | Negative correlation between amygdala and MPFC Glu and TMT and positive correlation between hippocampus Glu and RAVLT in all subjects |
| (Huber et al., 2018) | 10/20/0 | BD | Depressed | NR | NR | WCST,TMT, Stroop | ACC, POC | 3 | GABA | SV | PRESS 2D J-edit | 31–229 | W | - | Higher ACC GABA is associated with better WCST scores in BD, but not HC |
↑ Metabolite level is higher in patients than controls; ↓ Metabolite level is lower in patients than controls; - no group differences in metabolite levels
Abbreviations:
NR: not reported; n: number of subjects; FE: first episode patient; BD: bipolar disorder; MDD: major depressive disorder; HC: healthy controls
TE: Echo Time; SV: single voxel spectroscopy; PRESS: Point Resolved Spectroscopy W: water; Cr: creatine; Glu: glutamate; Gln: glutamine; Glx: glutamate+ glutamine; GABA: γ-aminobutyric acid
ACC: anterior cingulate cortex; MPFC: medial prefrontal cortex; POC: parieto-occipital cortex
MMSE: mini-mental state examination; RAVLT: rey auditory-verbal learning test; TMT: trail making test; VF: verbal fluency task; WASI: wechsler abbreviated scale for intelligence; WCST: wisconsin card sorting test; WTAR: wechsler test of adult reading