Memory extinction

Neurotransmitter and biogenic amine synthesized by neurons in the locus coeralus from tyrosine which controls behavioral state, postural tone, selective attention, mood and memory extinction, and is part of sympathoadrenal stress management system. 

The medial division of the prefrontal cortex seems to contribute to memory extinction as well. It is under negative control of the basolateral amygdala (Perez-Jaranay and Vives 1991 Garcia et al. 1999), most likely via activation... 

Cravatt et al. (2001) generated mutant mice lacking the faah gene (FAAH / mice) and characterized by altered nociceptive threshold, enhanced memory extinction, and increased sensitivity to the effects of exogenously administered ECs (Cravatt et al., 2001 Varvel et al., 2007). Such behavioral phenotype is compatible with the higher AEA levels measured in these mice (Cravatt et al., 2001). 

Milad, M. R. and Quirk, G. J. Neurons in medial prefrontal cortex signal memory for fear extinction. Nature 420 70-74, 2002. 

Keywords Learning Memory Fear Anxiety Conditioning Reconsolidation Extinction Sensitisation PTSD... 

As mentioned before, retrieval renders the consohdated memories labile again. It seems to depend on the test situation, whether this labile state is followed by reconsolidation or extinction of the aversive memory. Blockade of reconsohdation processes (e.g. by interrupting protein synthesis within the lateral amygdala), for instance, has led to extinction of the fear responses to the CS in an auditory fear-conditioning paradigm (Nader et al. 2000). 

Meaney MJ (2001) Maternal care, gene expression, and the transmission of individual differences in stress reactivity across generations. Annu Rev Neurosci 24 1161-1192 Medina JF, Christopher RJ, Mauk MD, LeDoux JE (2002) Parallels between cerebellum- and amygdala-dependent conditioning. Nat Rev Neurosci 3 122-131 Milad MR, Quirk GJ (2002) Neurons in medial prefrontal cortex signal memory for fear extinction. Nature 420 70-74... 

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Extinction is characterized by many of the same neural mechanisms as in fear acquisition. Activation of amygdala NMDA receptors by glutamate is essential (Myers and Davis 2004) and L-type VGCCs also contribute to extinction plasticity (Cain et al. 2002). Long-term extinction memory is altered by a munber of different neurotransmitters systems including GABA, NE, and... 

McGaugh JL, Roozendaal B (2002) Role of adrenal stress hormones in forming lasting memory in the brain. Curr Opin Neurobiol 12 205-210 McGaugh JL, Castellano C, Brioni J (1990) Picrotoxin enhances latent extinction of conditioned fear. Behav Neurosci 104 264-267... 

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