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Encoding of emotional memories depends on amygdala and hippocampus and their interactions

Abstract

We have studied patients with variable degrees of left hippocampal and amygdala pathology who performed a verbal encoding task during functional magnetic resonance imaging (fMRI) to assess the impact of pathology on emotional-memory performance and encoding-evoked activity. The severity of left hippocampal pathology predicted memory performance for neutral and emotional items alike, whereas the severity of amygdala pathology predicted memory performance for emotional items alone. Encoding-related hippocampal activity for successfully remembered emotional items correlated with the degree of left amygdala pathology. Conversely, amygdala-evoked activity with respect to subsequently remembered emotional items correlated with the degree of left hippocampal pathology. Our data indicate a reciprocal dependence between amygdala and hippocampus during the encoding of emotional memories.

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Figure 1: Recognition accuracy for each response type in patients and normal controls.
Figure 2: Structure–behavior relationships.
Figure 3: Structure–function relationships.
Figure 5: Anatomical specificity of hippocampal effects.
Figure 4: Amygdala–hippocampal reciprocal dependence during successful encoding of emotional words.

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Acknowledgements

We would like to thank the clinicians of the Department of Clinical and Experimental Epilepsy (J. Duncan, L. Sander, M. Walker, H. Cock, S. Sisodiya and M. Koepp) for referring patients to the study and P. Bartlett, Chief Radiographer at the Chalfont Centre for Epilepsy, for providing the volume and T2 data. M.P.R. is funded by a fellowship of the Medical Research Council, UK. R.J.D. is supported by a Wellcome Trust Programme Grant.

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Correspondence to Mark P Richardson.

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Supplementary information

Supplementary Fig. 1

Statistical parametric map (SPM) overlaid on sagittal and coronal sections of the average T1 image from all 16 patients studied. The highlighted voxels show a significant positive correlation between gray matter density and recognition accuracy for R responses to neutral items at P < 0.01 and a significant negative correlation between T2 signal and recognition accuracy for R responses to neutral items at P < 0.01. These are the only voxels in the entire brain to show both these effects. (JPG 16 kb)

Supplementary Note (PDF 9 kb)

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Richardson, M., Strange, B. & Dolan, R. Encoding of emotional memories depends on amygdala and hippocampus and their interactions. Nat Neurosci 7, 278–285 (2004). https://doi.org/10.1038/nn1190

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