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Descripción
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| Communication between the amygdala and the hippocampus has been proposed to support enhanced memory for emotional events. However, a mechanistic account of how these two structures interact during successful encoding of emotional ? unpleasant ? information is lacking. The aim of the present study is to investigate the oscillatory responses in amygdala and hippocampus associated with successful encoding of unpleasant scenes. Using direct intracranial recordings from the amygdala and the hippocampus in 8 patients being evaluated for medication-resistant epilepsy, we investigated the oscillatory responses associated with subsequent memory of unpleasant and neutral scenes from the IAPS database. Retrieval was assessed by a recognition test 24 h after encoding. All patients included in the study have intracranial depth electrodes implanted into the amygdala and the hippocampus (3 right, 4 left, and 1 bilateral). Encoding-related responses predicting subsequent recollection of unpleasant pictures, but not of neutral pictures, are observed in the amygdala from around 350ms post-stimulus onset in the fast gamma range (75-130 Hz). A lower-frequency gamma response (50-75 Hz) occurs in the hippocampus during successful encoding of both negative and neutral scenes at around 500ms. Gamma power in the two structures is significantly correlated during successful encoding of unpleasant pictures. Gamma is not only more pronounced for unpleasant remembered vs forgotten scenes, but its envelope is also more strongly modulated by alpha oscillations (11 Hz) in the amygdala and theta oscillations (8 Hz) in the hippocampus. We then calculated cross-frequency coupling between the amplitude of high-frequency activity and the phase of low-frequency oscillations within the two regions and between amygdala low frequencies phases and hippocampal gamma power. These analyses reveal that alpha phases in the amygdala (11 Hz) modulate amygdala gamma power, while amygdala theta phases (6-8 Hz) modulate hippocampal gamma power during successful encoding of unpleasant pictures. These results suggest that the amygdala modulates gamma oscillations in the hippocampus by phase amplitude coupling during the successful encoding of unpleasant pictures, thus playing a fundamental role in emotional memory formation. Our findings provide fundamental evidence for the understanding of the neural basis supporting negative memory formation. | |
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Internacional
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Nombre congreso
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50th Annual Meeeting of the Society for Neuroscience |
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Tipo de participación
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970 |
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Lugar del congreso
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Chicago, U.S.A. |
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Revisores
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ISBN o ISSN
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DOI
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Fecha inicio congreso
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19/10/2019 |
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Fecha fin congreso
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23/10/2019 |
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