Arrest of adult hippocampal neurogenesis in mice impairs single- but not multiple-trial contextual fear conditioning.
The role of adult hippocampal neurogenesis in contextual fear conditioning (CFC) is debated. Several studies demonstrated that blocking adult hippocampal neurogenesis in rodents impairs CFC, while several other studies failed to observe an impairment. We sought to determine whether different CFC methods vary in their sensitivity to the arrest of adult neurogenesis. Adult neurogenesis was arrested in mice using low-dose, targeted x-irradiation, and the effects of irradiation were assayed in conditioning procedures that varied in the use of a discrete conditioned stimulus, the number of trials administered, and the final level of conditioning produced. We demonstrate that irradiation impairs CFC in mice when a single-trial CFC procedure is used but not when multiple-trial procedures are used, regardless of the final level of contextual fear produced. In addition, we show that the irradiation-induced deficit in single-trial CFC can be rescued by providing preexposure to the conditioning context. These results indicate that adult hippocampal neurogenesis is required for CFC in mice only when brief training is provided.
Drew
Michael R
MR
Department of Psychiatry, Columbia University, New York, NY 10032, USA. .
Denny
Christine A
CA
Hen
Rene
R
D000161:Acoustic Stimulation / Q000009:adverse effects; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal; D003214:Conditioning, Classical / Q000502:physiology* / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D000089622:Doublecortin Domain Proteins; D005239:Fear; D005786:Gene Expression Regulation / Q000528:radiation effects; D006624:Hippocampus / Q000166:cytology* / Q000378:metabolism / Q000528:radiation effects; D008297:Male; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D055495:Neurogenesis / Q000502:physiology* / Q000528:radiation effects; D009479:Neuropeptides / Q000378:metabolism; D014965:X-Rays / Q000009:adverse effects
D000089622:Doublecortin Domain Proteins; D008869:Microtubule-Associated Proteins; D009479:Neuropeptides