title: Behavioral effects of deep brain stimulation of the anterior nucleus of thalamus, entorhinal cortex and fornix in a rat model of Alzheimer's disease.
abstract: BACKGROUND
  Recent clinical and preclinical studies have suggested that deep brain stimulation (DBS) can be used as a tool to enhance cognitive functions. The aim of the present study was to investigate the impact of DBS at three separate targets in the Papez circuit, including the anterior nucleus of thalamus (ANT), the entorhinal cortex (EC), and the fornix (FX), on cognitive behaviors in an Alzheimer's disease (AD) rat model.
  
  
  METHODS
  Forty-eight rats were subjected to an intrahippocampal injection of amyloid peptides 1-42 to induce an AD model. Rats were divided into six groups: DBS and sham DBS groups of ANT, EC, and FX. Spatial learning and memory were assessed by the Morris water maze (MWM). Recognition memory was investigated by the novel object recognition memory test (NORM). Locomotor and anxiety-related behaviors were detected by the open field test (OF). By using two-way analysis of variance (ANOVA), behavior differences between the six groups were analyzed.
  
  
  RESULTS
  In the MWM, the ANT, EC, and FX DBS groups performed differently in terms of the time spent in the platform zone (F(2,23) = 6.04, P < 0.01), the frequency of platform crossing (F(2,23) = 11.53, P < 0.001), and the percent time spent within the platform quadrant (F(2,23) = 6.29, P < 0.01). In the NORM, the EC and FX DBS groups spent more time with the novel object, although the ANT DBS group did not (F(2,23) = 10.03, P < 0.001). In the OF, all of the groups showed a similar total distance moved (F (1,42) = 1.14, P = 0.29) and relative time spent in the center (F(2,42) = 0.56, P = 0.58).
  
  
  CONCLUSIONS
  Our results demonstrated that DBS of the EC and FX facilitated hippocampus-dependent spatial memory more prominently than ANT DBS. In addition, hippocampus-independent recognition memory was enhanced by EC and FX DBS. None of the targets showed side-effects of anxiety or locomotor behaviors.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.forename: Wen-Han
authors.initials: WH
authors.lastname: Hu
authors.forename: De-Long
authors.initials: DL
authors.lastname: Wu
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University; Beijing Key Laboratory of Neurostimulation; Stereotactic and Functional Neurosurgery Laboratory, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100050, China.
authors.forename: Jian-Guo
authors.initials: JG
authors.lastname: Zhang
mesh_terms: D000544:Alzheimer Disease / Q000503:physiopathology* / Q000628:therapy*; D000818:Animals; D020643:Anterior Thalamic Nuclei / Q000502:physiology*; D046690:Deep Brain Stimulation / Q000379:methods*; D018728:Entorhinal Cortex / Q000502:physiology*; D020712:Fornix, Brain / Q000502:physiology*; D008297:Male; D008568:Memory / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D065853:Spatial Learning / Q000502:physiology