Hippocampal involvement in recollection but not familiarity across time: a prospective study.
For medial temporal lobe (MTL) involvement in memory formation, it is as yet unclear whether the MTL represents a single or dual (recollection/familiarity) memory system. A further controversial issue is whether or not the hippocampus is critical for the familiarity component of recognition memory. The present prospective fMRI study aimed to investigate changes of MTL involvement in recollection and familiarity at three time points following new learning: immediately after encoding, after 3 weeks and after 6 weeks. Significant hippocampal activation was observed for recollection relative to correct rejection responses at all three intervals. In addition, a decrease of signal changes in the perirhinal cortex was observed for the familiarity versus correct rejection contrasts. These findings support the idea that the MTL is a dual memory system. They also indicate a lasting hippocampal involvement in the recollection component of recognition memory and a decrease of perirhinal cortex activation associated with familiarity for time periods up to 6 weeks after new learning.
Suchan
Boris
B
Department of Neuropsychology, Institute of Cognitive Neuroscience, Ruhr-University Bochum, Germany. Boris.Suchan@ruhr-uni-bochum.de
Gayk
Anna E
AE
Schmid
Gebhard
G
Köster
Odo
O
Daum
Irene
I
D000328:Adult; D000704:Analysis of Variance; D004192:Discrimination, Psychological; D005260:Female; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D010364:Pattern Recognition, Visual; D010775:Photic Stimulation; D011446:Prospective Studies; D011930:Reaction Time / Q000502:physiology; D021641:Recognition, Psychology / Q000502:physiology*; D013997:Time Factors