Clinical Unit Cambridge, GlaxoSmithKline, United Kingdom ; Department of Psychology, University of Exeter, Exeter, United Kingdom.
PLoS One. 2013 Nov 11;8(11):e74133. doi: 10.1371/journal.pone.0074133. eCollection 2013.
It has been suggested that the BDNF Val66Met polymorphism modulates episodic memory performance via effects on hippocampal neural circuitry. However, fMRI studies have yielded inconsistent results in this respect. Moreover, very few studies have examined the effect of met allele load on activation of memory circuitry. In the present study, we carried out a comprehensive analysis of the effects of the BDNF polymorphism on brain responses during episodic memory encoding and retrieval, including an investigation of the effect of met allele load on memory related activation in the medial temporal lobe. In contrast to previous studies, we found no evidence for an effect of BDNF genotype or met load during episodic memory encoding. Met allele carriers showed increased activation during successful retrieval in right hippocampus but this was contrast-specific and unaffected by met allele load. These results suggest that the BDNF Val66Met polymorphism does not, as previously claimed, exert an observable effect on neural systems underlying encoding of new information into episodic memory but may exert a subtle effect on the efficiency with which such information can be retrieved.
有人认为，BDNF Val66Met 多态性通过对海马神经回路的影响来调节情景记忆表现。然而，在这方面，功能磁共振成像（fMRI）研究的结果并不一致。此外，很少有研究检查过 met 等位基因负荷对记忆回路激活的影响。在本研究中，我们对 BDNF 多态性对情景记忆编码和检索期间大脑反应的影响进行了全面分析，包括研究 met 等位基因负荷对内侧颞叶记忆相关激活的影响。与之前的研究相比，我们没有发现 BDNF 基因型或 met 负荷在情景记忆编码期间的作用证据。Met 等位基因携带者在成功检索时右侧海马体的激活增加，但这是对比特异性的，不受 met 等位基因负荷的影响。这些结果表明，BDNF Val66Met 多态性并没有像之前声称的那样，对将新信息编码到情景记忆的神经系统产生可观察到的影响，但可能对检索此类信息的效率产生微妙的影响。
