Fornix deep brain stimulation enhances acetylcholine levels in the hippocampus

Sarah Hescham, Ali Jahanshahianvar, J.V. Schweimer, S.N. Mitchell, G. Carter, A. Blokland, T. Sharp, Yasin Temel

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Abstract

Deep brain stimulation (DBS) of the fornix has gained interest as a potential therapy for advanced treatment-resistant dementia, yet the mechanism of action remains widely unknown. Previously, we have reported beneficial memory effects of fornix DBS in a scopolamine-induced rat model of dementia, which is dependent on various brain structures including hippocampus. To elucidate mechanisms of action of fornix DBS with regard to memory restoration, we performed c-Fos immunohistochemistry in the hippocampus. We found that fornix DBS induced a selective activation of cells in the CA1 and CA3 subfields of the dorsal hippocampus. In addition, hippocampal neurotransmitter levels were measured using microdialysis before, during and after 60 min of fornix DBS in a next experiment. We observed a substantial increase in the levels of extracellular hippocampal acetylcholine, which peaked 20 min after stimulus onset. Interestingly, hippocampal glutamate levels did not change compared to baseline. Therefore, our findings provide first experimental evidence that fornix DBS activates the hippocampus and induces the release of acetylcholine in this region.
Original languageEnglish
Pages (from-to)4281–4286
Number of pages6
JournalBrain Structure & Function
Volume221
Issue number8
Early online date24 Nov 2015
DOIs
Publication statusPublished - Nov 2016

Keywords

  • Deep brain stimulation
  • Memory
  • Fornix
  • Hippocampus
  • Acetylcholine
  • ALZHEIMERS-DISEASE
  • RAT-BRAIN
  • MEMORY

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