Neural effects of continuous theta-burst stimulation in macaque parietal neurons

Theta-burst transcranial magnetic stimulation (TBS) has become a standard non-invasive technique to induce offline changes in cortical excitability in human volunteers. Yet, TBS suffers from a high variability across subjects. A better knowledge about how TBS affects neural activity in vivo could uncover its mechanisms of action and ultimately allow its mainstream use in basic science and clinical applications. To address this issue, we applied continuous TBS (cTBS, 300 pulses) in awake behaving rhesus monkeys and quantified its after-effects on neuronal activity. Overall, we observed a pronounced, long-lasting, and highly reproducible reduction in neuronal excitability after cTBS in individual parietal neurons, with some neurons also exhibiting periods of hyperexcitability during the recovery phase. These results provide the first experimental evidence of the effects of cTBS on single neurons in awake behaving monkeys, shedding new light on the reasons underlying cTBS variability.

Automated summary

Theta-burst transcranial magnetic stimulation (TBS) is a standard non-invasive technique for inducing offline changes in cortical excitability, but it exhibits high variability across subjects. By applying continuous TBS (cTBS) to awake behaving rhesus monkeys, a pronounced, long-lasting, and highly reproducible reduction in neuronal excitability was observed, shedding new light on the reasons underlying TBS variability.