Dodds, Chris M4; Henson, Richard N5; Suckling, John5; Miskowiak, Kamilla W1; Ooi, Cinly5; Tait, Roger5; Soltesz, Fruzsina5; Lawrence, Phil5; Bentley, Graham5; Maltby, Kay5; Skeggs, Andrew5; Miller, Sam R5; McHugh, Simon5; Bullmore, Edward T5; Nathan, Pradeep J5
1 Psykiatrisk Center København afd O - Rigshospitalet, Psykiatrisk Center København, Mental Health Services, The Capital Region of Denmark2 Psykiatrisk Center København afd O - Østerbro og Indre By, Psykiatrisk Center København, Mental Health Services, The Capital Region of Denmark3 Psykiatrisk Center København, Mental Health Services, The Capital Region of Denmark4 Clinical Unit Cambridge, GlaxoSmithKline, United Kingdom ; Department of Psychology, University of Exeter, Exeter, United Kingdom.5 unknown
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.