title: BDNF deletion or TrkB impairment in amygdala inhibits both appetitive and aversive learning.
abstract: Brain-derived neurotrophic factor (BDNF) is known to have an integral role in establishing stable memories after learning events. The neuroplasticity induced by Pavlovian fear conditioning has likewise been shown to rely on interactions between BDNF and its principal receptor, tyrosine kinase receptor B (TrkB), in the amygdala after training. Although the necessity of amygdala bdnf expression and TrkB activation for associative learning within aversive contexts has been explored, it is unclear to what extent this interaction is involved in appetitive learning. It is also unclear whether the noted increases in amygdala BDNF after fear conditioning are due to local gene transcription and translation or anterograde transmission from cortical regions. To address both of these questions, we used two lentiviral approaches in mice, using both fear conditioning and cocaine-conditioned place preference (CPP), during acquisition and extinction. First, we decreased expression of bdnf mRNA in the amygdala of homozygous floxed mice with a Cre-expressing virus. In a second set of studies, we infused a virus that expressed a dominant-negative TrkB isoform into the same region. These approaches significantly impaired consolidation of fear conditioning and cocaine-CPP, as well as extinction of CPP. Together, these data suggest that BDNF-TrkB signaling is critical for amygdala-dependent learning of both appetitive and aversive emotional memories.
authors: Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163, Department of Psychiatry and Behavioral Sciences, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30329, and Howard Hughes Medical Institute, Chevy Chase, Maryland 20815.
authors: Scott A
authors: SA
authors: Heldt
authors: Kelsey
authors: K
authors: Zimmermann
authors: Kathryn
authors: K
authors: Parker
authors: Meriem
authors: M
authors: Gaval
authors: David
authors: D
authors: Weinshenker
authors: Kerry J
authors: KJ
authors: Ressler
mesh_terms: D000679:Amygdala / Q000378:metabolism*; D000818:Animals; D001066:Appetite; D001245:Association Learning / Q000502:physiology*; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism*; D008568:Memory / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D020813:Receptor, trkB / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D020813:Receptor, trkB
keywords: BDNF; TrkB; amygdala; learning