A new study from Umea University shows that KIBRA(WWC1) T allele carriers have better memories than non-carriers. Up until now, a 2006 study had reigned in the science world, claiming that while KIBRA T allele carriers showed better memory, non-carriers brain compensated for this discrepancy by overworking their hippocampus. This recent study, performed on 2,230 subjects, proved not only that KIBRA T allele carriers performed better in episodic memory, but that they actually have higher activation of the hippocampus than non-carriers.
In the 2006 study that found this T-variant , scientists screened the entire genome to find a genetic variation linked with episodic memory. Patients who carried the T Allele (TT, CT) in a common C/T polymorphis in the KIBRA gene were shown to have better episodic memory that non-carriers (CC). However, later in the study, 30 subjects were photographed using magnetic cameras (fMRIs) during a memory task, allegedly showing that non-carriers actually had greater activation of their hippocampus than carriers. With this information, the 2006 study concluded that non-carriers needed to compensate for their poorer memory function with increased activation of their hippocampus in order to keep up with the memory levels of T carriers.
The hippocampus is important in this equation because it plays a significant role in the formation of new memories about experienced events(episodic or autobiographical memory). We have 2 hippocampus, due to the bilateral symmetry in our brain, so we can still retain near-normal memory even with one damaged hippocampus. However, if both were to be hemispheres were damaged, the brain would have difficulty forming new memories and retaining old ones (amnesia). Shown in fMRIs, activity in the hippocampus is linked with episodic memories being formed.
The newest study performed recently by Umea University took 83 or their 2230 subjects and did an fMRI scan, proving that non-carriers of the T allele actually have less hippocampus function. After disproving the 2006 study, the conclusion now remains that the T allele plays a role in improving memory by increasing the hippocampus functions.