KIBRA polymorphism is related to enhanced memory and elevated hippocampal processing

Abstract

Several studies have linked the KIBRA rs17070145 T polymorphism to superior episodic memory in healthy humans. One study investigated the effect of KIBRA on brain activation patterns (Papassotiropoulos et al., 2006) and observed increased hippocampal activation in noncarriers of the T allele during retrieval. Noncarriers were interpreted to need more hippocampal activation to reach the same performance level as T carriers. Using large behavioral (N = 2230) and fMRI (N = 83) samples, we replicated the KIBRA effect on episodic memory performance, but found increased hippocampal activation in T carriers during episodic retrieval. There was no evidence of compensatory brain activation in noncarriers within the hippocampal region. In the main fMRI sample, T carriers performed better than noncarriers during scanning but, importantly, the difference in hippocampus activation remained after post hoc matching according to performance, sex, and age (N = 64). These findings link enhanced memory performance in KIBRA T allele carriers to elevated hippocampal functioning, rather than to neural compensation in noncarriers.

Figure 1.

a, Increased right hippocampal activation in KIBRA rs17070145 T allele carriers (CT/TT genotype) relative to noncarriers (CC) during retrieval. b, Percentage signal change in local maximum of right (x, y, z = 36, −28, −10) and left (x, y, z = −16, −34, −2) hippocampus (HC). a, b, Matched groups (N = 64).