The effect of gamma oscillations in boosting primary motor cortex plasticity is greater in young than older adults

Contribution of TMS and TMS-EEG to the Understanding of Mechanisms Underlying Physiological Brain Aging

“…In contrast to PAS studies, M1 excitability increased in a comparable way between the two groups after iTBS [172]. Similar findings were also obtained in more recent research, indicating that iTBS-induced LTP-like plasticity of M1 is not affected by aging [173,174].…”

“…Recent evidence suggests that the amount of NIBS-induced plasticity of M1 changes by concurrently modulating cortical gamma oscillations through transcranial alternating current stimulation (tACS), and this effect has been interpreted as reflecting gating phenomena [18,[184][185][186]. However, gamma-tACS has been demonstrated to boost LTP-like plasticity induced by iTBS to a larger extent in young than older adults and, in the latter group, the effect of gamma-tACS decreased with increasing age [174]. In summary, unlike synaptic plasticity mechanisms, which seem to be altered only in part by the aging process, the existing evidence point to a higher susceptibility of metaplasticity processes by physiological aging.…”

Clinical neurophysiology of Parkinson’s disease and parkinsonism

“…TBS-induced LTP/LTD-like plasticity can be shaped by concurrent transcranial alternating current stimulation (tACS), a non-invasive stimulation that entrains brain oscillations, delivered at the γ frequency ( Suppa et al, 2022a ). Indeed, iTBS-induced LTP-like plasticity can be boosted and prolonged by concurrent γ-tACS, the effect depends on changes in GABA A receptor mediated interneuronal activity ( Guerra et al, 2018 , Guerra et al, 2021a , Guerra et al, 2020b ). Using a combined iTBS-γ tACS, a study demonstrated that driving γ oscillations restore the LTP-like plasticity in PD patients ( Guerra et al, 2020a ).…”

GABAergic Modulation in Movement Related Oscillatory Activity: A Review of the Effect Pharmacologically and with Aging

“…With healthy aging there appears to be a general decrease in inhibitory tone [ 71 72 73 76 ] noted by alterations in movement related synchronizations, decreased GABA levels [ 70 71 72 73 74 ], and reduced inhibition by measuring short-interval intracortical inhibition (SICI) [ 73 74 77 ]. These noted alterations in inhibitory signaling are potentially clinically significant.…”

“…Gamma oscillation transcranial alternating current stimulation (gamma-tACS) is known to modulate and enhance GABAergic neurotransmission. However, within older adults (65.3+/– 9.5 years old), this modulation is reduced and negatively correlated with age [ 77 ]. Further, subjects with less increase in GABA inhibition from gamma-tACS show slower short-term learning [ 78 ].…”