Effects of the BDNF Val66Met polymorphism and met allele load on declarative memory related neural networks.
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.
Clinical Unit Cambridge, GlaxoSmithKline, United Kingdom ; Department of Psychology, University of Exeter, Exeter, United Kingdom.
Chris M
CM
Dodds
Richard N
RN
Henson
John
J
Suckling
Kamilla W
KW
Miskowiak
Cinly
C
Ooi
Roger
R
Tait
Fruzsina
F
Soltesz
Phil
P
Lawrence
Graham
G
Bentley
Kay
K
Maltby
Andrew
A
Skeggs
Sam R
SR
Miller
Simon
S
McHugh
Edward T
ET
Bullmore
Pradeep J
PJ
Nathan
D000328:Adult; D000483:Alleles; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics* / Q000378:metabolism; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D061212:Memory, Episodic; D008875:Middle Aged; D009415:Nerve Net / Q000502:physiology*; D011110:Polymorphism, Genetic
D019208:Brain-Derived Neurotrophic Factor; C579455:BDNF protein, human