Frontiers in Neuroscience (Feb 2023)

Dose and time-dependence of acute intermittent theta-burst stimulation on hippocampus-dependent memory in parkinsonian rats

  • Yixuan Wang,
  • Jian Liu,
  • Yanping Hui,
  • Zhongheng Wu,
  • Ling Wang,
  • Xiang Wu,
  • Yihua Bai,
  • Qiaojun Zhang,
  • Libo Li

DOI
https://doi.org/10.3389/fnins.2023.1124819
Journal volume & issue
Vol. 17

Abstract

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BackgroundThe treatment options for cognitive impairments in Parkinson’s disease (PD) are limited. Repetitive transcranial magnetic stimulation has been applied in various neurological diseases. However, the effect of intermittent theta-burst stimulation (iTBS) as a more developed repetitive transcranial magnetic stimulation paradigm on cognitive dysfunction in PD remains largely unclear.ObjectiveOur aim was to explore the effect of acute iTBS on hippocampus-dependent memory in PD and the mechanism underlying it.MethodsDifferent blocks of iTBS protocols were applied to unilateral 6-hydroxidopamine-induced parkinsonian rats followed by the behavioral, electrophysiological and immunohistochemical analyses. The object-place recognition and hole-board test were used to assess hippocampus-dependent memory.ResultsSham-iTBS and 1 block-iTBS (300 stimuli) didn’t alter hippocampus-dependent memory, hippocampal theta rhythm and the density of c-Fos- and parvalbumin-positive neurons in the hippocampus and medial septum. 3 block-iTBS (900 stimuli) alleviated 6-hydroxidopamine-induced memory impairments, and increased the density of hippocampal c-Fos-positive neurons at 80 min post-stimulation but not 30 min compared to sham-iTBS. Interestingly, 3 block-iTBS first decreased and then increased normalized theta power during a period of 2 h following stimulation. Moreover, 3 block-iTBS decreased the density of parvalbumin-positive neurons in the medial septum at 30 min post-stimulation compared to sham-iTBS.ConclusionThe results indicate that multiple blocks of iTBS elicit dose and time-dependent effects on hippocampus-dependent memory in PD, which may be attributed to changes in c-Fos expression and the power of theta rhythm in the hippocampus.

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