Overview
Whats the deal with emotional enhancement of memory? How are different associations (item-emotion, item-context) handled in and out of the MTL? Along with the amygdala and hippocampus (HPC), what role do the perirhinal cortex (PRC) and parahippocampal cortex (PHC) play in encoding emotional and contextual information? etc. etc.
Methods
- Episodic memory paradigm in which encoding was scanned:
- viewed blocks of 4 trials of either negatively emotionally valenced images or neutral images
- each mini-block required participants to answer one of two different questions about each image, providing 2 different source contexts
- the definition of context here is certainly a little lose but I think it follows the ideas about mental context well
- Next day subs did recognition memory (R/F/N) and a source memory (Y/N and Sure/Unsure)
- hi-res (1mm^3 voxel size) fMRI of encoding, relate memory back to neural activity at the time of encoding
Results
In short, authors report double dessociation of roles in the MTL:
- amygdala and PRC show greater subsequent item mem. effects
- HPC and PHC show greater subsequent context mem. effects
- Outside of MTL:
- Occipital-temporal predicts item memory, stronger for emotion vs neutral
- Posterior-medial network predicts context memory, regardless of emotional content
Conclusions
- Data support emotional binding account of memory
- amyg. important for item-emotion binding
- HPC important for item-context binding
- emotional recollection does not depend on context binding
- this is different from other accounts of recollection, which frame always in term of reinstating item-context information
- helps interpret data in which there is enchancement of emotional item but no enhancement for contextual details
- boots intrinsic and not extrinsic associations for an emotional item
- Important to realize that this is an experimental case of emotionless context
- in the real world, contexts often carry emotional content
- emotional items bind more strongly to related contexts
- in that case, predict more HPC binding of emotional item to context