Representations of recent and remote autobiographical memories in hippocampal subfields.
Bottom Line: The hippocampus has long been implicated in supporting autobiographical memories, but little is known about how they are instantiated in hippocampal subfields.Moreover, while subfields in the anterior hippocampus contained information about both recent (2 weeks old) and remote (10 years old) autobiographical memories, posterior CA3 and DG only contained information about the remote memories.Thus, the hippocampal subfields are differentially involved in the representation of recent and remote autobiographical memories during vivid recall.
Affiliation: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, United Kingdom.Show MeSH
Mentions: We first examined whether it was possible to discriminate between the three recent autobiographical memories from the activity across voxels in each of the four subfields. If information was present in the patterns of fMRI activity that enabled discrimination between the three recent memories, then the classifier would produce a classification result significantly above chance (33%). We found that information was present in CA1 and subiculum which permitted successful detection of the three recent autobiographical memories significantly above chance [CA1: t(11) = 3.031, P = 0.011; subiculum: t(11) = 2.600, P = 0.025; Fig. 2, blue line]. This was not the case for CA3 [t(11) = 1.513, P = 0.158] or DG [t(11) = 1.663, P = 0.125], where the classifiers’ performance was not significantly different from chance. We then examined the remote memories. In contrast to the recent, we found that the three remote autobiographical memories could be detected significantly above chance in all four subfields [CA1: t(11) = 3.786, P = 0.003; CA3: t(11) = 3.773, P = 0.003; DG: t(11) = 3.372, P = 0.006; subiculum: t(11) = 4.227, P = 0.001; Fig. 2, red line).
Affiliation: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, United Kingdom.