Table 2:
GABA and cognition in schizophrenia
| Author | n (control/ patient) | Illness stage | Medication status | Cognitive domain | Region | Tesla | Acquisition | MRS Sequence | TE (ms) | Reference | Metabolite level group difference | Associations between metabolites and cognition |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| (Yoon et al., 2010) | 13/13 | mixed | mixed | OSSS | Calcarine sulci | 3 | SV | MEGA- PRESS | 68 | Cr | ↓GABA | GABA was positively correlated to the magnitude of OSSS in the combined SZ and HC group |
| (Kegeles et al., 2012) | 22/32 | Chronic | Mixed | N-Back | MPFC, DLPFC | 3 | SV | MEGA-PRESS | 68 | Cr, W | ↑GABA in MPFC in unmedicated vs HC; - DLPFC | No associations |
| (Kelemen et al., 2013) | 20/28 | FEP | naïve | Visual processing | Occipital cortex | 3 | SV | MEGA- PRESS | 68 | Cr | ↓GABA | No associations between GABA and visual contrast sensitivity |
| (Rowland et al., 2013b) | 20/21 | Chronic young (11/10); old (10/10) | Medicated | RBANS | ACC, CSO | 3 | SV | MEGA- PRESS | 68/ 35 | W | Trend for ↓GABA in old SZ vs old HC | ACC GABA was positively correlated with RBANS attention score in the combined SZ and HC group |
| (Marsman et al., 2014) | 23/17 | Chronic | Medicated | WAIS | MPFC, POC | 7 | SV | MEGA-sLASER | 74 | Cr | ↓GABA in MPFC | MPFC GABA negatively associated with WAIS scores in SZ, but not HC |
| (Chen et al., 2014) | 12/12 | Chronic | mixed | Modified Sternberg working memory task (EEG) | Left DLPFC | 3 | SV | MEGA-PRESS | 68 | W | - | No associations Left DLPFC GABA was positively correlated with the gamma amplitudes during both the rest and working memory task in the combined SZ and HC group |
| (Rowland et al., 2016a) | 77/60 | Chronic young (40/29); old (37/31) | mixed | Digit symbol coding test, DST and UPSA | ACC | 3 | SV | MEGA- PRESS | 68 | W | Age strongly predicted GABA levels in SZ | ACC GABA was positively associated with the DST in SZ, but not HC |
| (Rowland et al., 2016b) | 53/45 | Chronic | mixed | DST, auditory MMN (EEG) | ACC | 3 | SV | MEGA-PRESS | 6.5/ 68 | W | - | Higher GABA was correlated with better DST working memory and processing speed in SZ, but not HC |
| (Reid et al., 2018) | 21/21 | FEP | Medicated | RBANS | ACC | 7 | SV | STEAM | 5 | W | - | Negative association between GABA and RBANS total score, immediate memory and language subscales in SZ, 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:
n: number of subjects; FEP: first episode psychosis patients; SZ: patients with schizophrenia; HC: healthy controls
TE: Echo Time; SV: single voxel spectroscopy; MEGA-PRESS: Meshcher-Garwood Point Resolved Spectroscopy; MEGA-sLASER: MEGA- semi localization by adiabatic selective refocusing sequence; STEAM: STimulated Echo Acquisition Mode; W: water; Cr: creatine; GABA: γ-aminobutyric acid
ACC: anterior cingulate cortex; CSO: centrum semiovale; DLPFC: dorsolateral prefrontal cortex; MPFC: medial prefrontal cortex; POC: parieto-occipital cortex
DST: digit sequencing task; EEG: Electroencephalogram; MMN – Mismatch Negativity; OSSS: orientation specific surround suppression; RBANS: repeatable battery for the assessment of neuropsychological status; UPSA: UCSD performance based skills assessment; WAIS: wechsler adult intelligence scale