title: Spatial memory impairment in Morris water maze after electroconvulsive seizures.
abstract: OBJECTIVE
  Electroconvulsive therapy (ECT) is one of the most efficient treatments for severe major depression, but some patients suffer from retrograde memory loss after treatment. Electroconvulsive seizures (ECS), an animal model of ECT, have repeatedly been shown to increase hippocampal neurogenesis, and multiple ECS treatments cause retrograde amnesia in hippocampus-dependent memory tasks. Since recent studies propose that addition of newborn hippocampal neurons might degrade existing memories, we investigated whether the memory impairment after multiple ECS treatments is a cumulative effect of repeated treatments, or if it is the result of a delayed effect after a single ECS.
  
  
  METHODS
  We used the hippocampus-dependent memory task Morris water maze (MWM) to evaluate spatial memory. Rats were exposed to an 8-day training paradigm before receiving either a single ECS or sham treatment and tested in the MWM 24 h, 72 h, or 7 days after this treatment, or multiple (four) ECS or sham treatments and tested 7 days after the first treatment.
  
  
  RESULTS
  A single ECS treatment was not sufficient to cause retrograde amnesia whereas multiple ECS treatments strongly disrupted spatial memory in the MWM.
  
  
  CONCLUSIONS
  The retrograde amnesia after multiple ECS is a cumulative effect of repeated treatments rather than a delayed effect after a single ECS.
authors.affiliation: Department of Clinical Sciences Lund,Psychiatric Neuromodulation Unit,Lund University,Lund,Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Svensson
authors.affiliation: Department of Clinical Sciences Lund,Psychiatric Neuromodulation Unit,Lund University,Lund,Sweden.
authors.forename: Thord
authors.initials: T
authors.lastname: Hallin
authors.affiliation: Department of Clinical Sciences Lund,Psychiatric Neuromodulation Unit,Lund University,Lund,Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Broms
authors.affiliation: Department of Clinical Sciences Lund,Psychiatric Neuromodulation Unit,Lund University,Lund,Sweden.
authors.forename: Joakim
authors.initials: J
authors.lastname: Ekstrand
authors.affiliation: Department of Clinical Sciences Lund,Psychiatric Neuromodulation Unit,Lund University,Lund,Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Tingström
mesh_terms: D000648:Amnesia, Retrograde / Q000209:etiology / Q000503:physiopathology*; D000818:Animals; D004195:Disease Models, Animal; D004565:Electroconvulsive Therapy / Q000009:adverse effects; D004597:Electroshock / Q000009:adverse effects*; D006624:Hippocampus / Q000503:physiopathology*; D008297:Male; D018782:Maze Learning; D051381:Rats; D012640:Seizures / Q000523:psychology*; D065852:Spatial Memory / Q000502:physiology*
keywords: Morris water maze; electroconvulsive seizures; rat; retrograde amnesia