Is there a negative correlation between explicit memory and hippocampal volume?

The aim of this research was to study the relationship between explicit memory and hippocampal volume. Seventy healthy adults were administered one implicit memory test and one explicit memory (EM) test and underwent magnetic resonance imaging. The major finding was a negative correlation between the EM test and the right hippocampus/brain volume ratio (t = -0.25, P = 0.03) and the left hippocampus/brain volume ratio (t = -0.27, P = 0.02). This finding is not consistent with pathologic findings, which tend to show a relationship between decrease in memory performance and hippocampal atrophy. This discrepancy is discussed. Copyright 1999 Academic Press.