GABAergic system and TMS plasticity protocols
| Study | Design (n) | Age, yr* | Male, % | Protocol | Drug (dose) | TMS target | Mechanism of action | Effect |
|---|---|---|---|---|---|---|---|---|
| Healthy participants | ||||||||
| McDonnell et al. (81) | C/O (7) | 28.7 ± 7.9 | 42.86 | PAS(N20) + 2 ms | Baclofen (50 mg) | M1 | GABAB agonist | Blocked LTP-like |
| Heidegger et al. (82) | C/O (9) | 21–30 | 60 | PAS(N20) + 2 ms | Diazepam (20 mg) | M1 | GABAA agonist | Decreased LTP-like |
| Heidegger et al. (82) | C/O (8) | 21–30 | 60 | PAS(N20) + 2 ms | Tiagabine (15 mg) | M1 | GABA reuptake inhibitor | Decreased LTP-like |
| MCI | ||||||||
| Martorana et al. (84) | OL (10) | 61.9 ± 1.9 | 60 | iTBS cTBS | Homotaurine (100 mg/d for 4 wk) | M1 | GABAA and GABAB partial agonist | No effect |
C/O = crossover; cTBS = continuous theta-burst stimulation; GABA = γ-aminobutyric acid; GABAA = γ-aminobutyric acid type A; GABAB = γ-aminobutyric acid type B; iTBS = intermittent theta-burst stimulation; LTP = long-term potentiation; M1 = motor cortex; MCI = mild cognitive impairment; OL = open label; PAS = paired associated stimulation; TMS = transcranial magnetic stimulation.
↵* Data are presented as either mean ± standard deviation or as a range.