Abstract
Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive tool commonly used to drive neural plasticity in the young adult and aged brain. Recent data from mouse models have shown that even at low intensities (0.12 Tesla), rTMS can drive neuronal and glial plasticity in the motor cortex. However, the physiological mechanisms underlying low intensity rTMS (LI-rTMS) induced plasticity and whether these are altered with normal ageing are unclear. Using longitudinal in vivo 2-photon microscopy, we investigated the effect of LI-rTMS on the structural plasticity of pyramidal neuron dendritic spines in the motor cortex following a single train of LI-rTMS (in young adult and aged animals) or the same LI-rTMS train administered on 4 consecutive days (in young adult animals only). We found that LI-rTMS altered the rate of dendritic spine losses and gains, dependent on the number of stimulation sessions and that a single session of LI-rTMS was effective in driving structural synaptic plasticity in both young adult and aged mice. To our knowledge, these results provide the first in vivo evidence that rTMS drives synaptic plasticity in the brain and uncovers structural synaptic plasticity as a key mechanism of LI-rTMS induced plasticity.
Competing Interest Statement
The authors have declared no competing interest.
