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. Author manuscript; available in PMC: 2010 Mar 3.
Published in final edited form as: N Engl J Med. 2000 Aug 17;343(7):450–456. doi: 10.1056/NEJM200008173430701

Figure 3. MRI Signal Intensity in the Hippocampus.

Figure 3

Panel A shows the percent increases in signal intensity during learning or recall periods as compared with periods of rest, for the hippocampus and parahippocampal gyrus, averaged among subjects in each group. These increases are plotted for the nine minutes of the experiment; the peaks indicate periods of learning or recalling the word pairs, whereas the valleys indicate periods when the subjects were at rest. In both groups the signal intensity increased during the learning or recall periods as compared with the interspersed periods of rest, though these increases were larger in the carriers of the APOE ε4 allele. Panel B shows the mean (±SD) percent change in the MRI signal intensity in the hippocampus and parahippocampal gyrus during each of the six periods of recall. The response among the carriers of the APOE ε4 allele was consistently larger than the response among the carriers of the APOE ε3 allele.