Hindbrain Stimulation Modulates Object Recognition Discrimination Efficiency and Hippocampal Synaptic Connections

Abstract

(1) Background: The cerebellum is well known to have functionalities beyond the control of motor function. However, brain stimulation studies have not explored the potential of this region to impact downstream processes which are imperative to multiple neurological conditions. Our study aimed to look at preliminary evidence that hindbrain-targeted repetitive transcranial magnetic stimulation (rTMS) in mice could alter motor, cognitive and anxiety measures; (2) Methods: Male B6129SF2/J mice (n = 16) were given rTMS (n = 9) over lambda at 10 Hz for 10 min or Sham (n = 7) for 14 consecutive days. Mice then underwent a battery of behavioral measures. (3) Results: In the object recognition test, only rTMS-treated mice distinguished between the novel object at 5 min, whereas those that received Sham treatment continued to improve discrimination from 5 to 10 min. Additionally, over the 10 min test phase, rTMS-stimulated mice explored the objects less than the Sham mice. This was accompanied by increased colocalization of presynaptic and postsynaptic markers in the hippocampus in the rTMS mice (4) Conclusions: Hindbrain rTMS stimulation elicits improved processing speed in the object recognition test via structural plasticity mechanisms in the hippocampus and could provide additional ways of targeting these important substructures of the brain.

Keywords

• repetitive transcranial magnetic stimulation
• neuromodulation
• hindbrain
• synaptic plasticity
• processing speed