The impact of genetic variation in comt and bdnf on resting-state functional connectivity

Genetic imaging techniques allow investigation of the mechanisms by which genetic variants influence brain structure and function. The default mode network (DMN) is characterized by a default state of neuronal activity in the brain that is linked to core processes of human cognition. This study examined the role of catechol-O-methyl transferase (COMT) and brain-derived neurotrophic factor (BDNF) polymorphisms on functional connectivity between brain areas. Twenty-three healthy volunteers underwent a resting-state functional magnetic resonance imaging scan and genotyping of COMT and BDNF single nucleotide polymorphisms (SNPs). A resting-state functional connectivity map was created using the posterior cingulate cortex (PCC) as a seed region. The Val/Val homozygote group of the COMT Val158Met SNP showed significantly greater DMN connectivity in the medial and superior frontal gyri and cerebellum compared with the Met allele carrier group. For the BDNF Val66Met SNP, connectivity between the PCC and precuneus was stronger in the Val/Val homozygote group than in the Met allele carrier group. Different patterns of DMN connectivity related to BDNF and COMT SNPs were observed in this study. These findings suggest interaction between genes and functional connectivity in the brain and indicate that altered functional connectivity may be an endophenotype of cognitive vulnerability. (c) 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 97102, 2012