The paper

This repository includes scripts and data for the following paper:

Ritchey, M., Wang, S.-F., Yonelinas, A.P., & Ranganath C. (2018). Dissociable medial temporal pathways for encoding emotional item and context information - in press at Neuropsychologia

Abstract

Emotional experiences are typically remembered with a greater sense of recollection than neutral experiences, but memory benefits for emotional items do not typically extend to their source contexts. Item and source memory have been attributed to different subregions of the medial temporal lobes (MTL), but it is unclear how emotional item recollection fits into existing models of MTL function and, in particular, what is the role of the hippocampus. To address these issues, we used high-resolution functional magnetic resonance imaging (fMRI) to examine MTL contributions to successful emotional item and context encoding. The results showed that emotional items were recollected more often than neutral items. Whereas amygdala and perirhinal cortex (PRC) activity supported the recollection advantage for emotional items, hippocampal and parahippocampal cortex activity predicted subsequent source memory for both types of items, reflecting a double dissociation between anterior and posterior MTL regions. In addition, amygdala activity during encoding modulated the relationships of PRC activity and hippocampal activity to subsequent item recollection and source memory, respectively. Specifically, whereas PRC activity best predicted subsequent item recollection when amygdala activity was relatively low, hippocampal activity best predicted source memory when amygdala activity was relatively high. We interpret these findings in terms of complementary compared to synergistic amygdala-MTL interactions. The results suggest that emotion-related enhancements in item recollection are supported by an amygdala-PRC pathway, which is separable from the hippocampal pathway that binds items to their source context.

Resources

I have shared a few key scripts in the analysis folder along with some corresponding data files and reports. All files can be found here.

The general flow of the included scripts is as follows:

• Analyze the behavioral data: analysis/MemoHR_behavior_paper.Rmd
  • The formatted report (with code) can be found here.
  • Data output from this script can be found here: data/behavior_processedData.Rdata
• Use the scored behavioral data to generate csv files containing all info necessary to set up fMRI model regressors: analysis/MemoHR_itemSourceModel_spec.R
• Use those csv files to generate the SPM regressor & contrast files: analysis/generate_regs_cons_ItemSource.m
• Run the model for each subject: analysis/batch_model_ItemSourceDM.m
• Extract mean contrast estimates from native-space ROIs: analysis/output_indivroi_cons_all_new.m
  • Data output from this script can be found here: data/cons_ashs_ItemSourceDM_rf_new.csv
• Run the ROI analyses on those contrast estimates: analysis/MemoHR_ROI_analysis_paper.Rmd
  • The formatted report (with code) can be found here. This includes code for generating the ROI maps shown above.
  • Data output from this script can be found here: data/MemoHR_AnatROI_Data_ItemSource.Rdata
• Run an analysis linking ROI activity to single-trial memory outcomes: analysis/MemoHR_ROI_analysis_predictmem_paper.Rmd
  • Single-trial input data can be found here: data/cons_ashs_betas_ItemSourceDM_rf_new_ST.csv
  • The formatted report (with code) can be found here.

PsychoPy task scripts are included in the task folder. The practice versions should be runnable with the practice stimuli provided (pictures of my dog and cat, not actually included in the experiment). You can request the actual task stimuli here.

Comments?

Please direct any comments to Maureen Ritchey, maureen.ritchey at bc.edu. Notice a bug? Please tell me. Want to use any of these scripts? Go right ahead. Unfortunately I cannot provide any support for you to adapt them to your own data.