Triple Dissociation Revisited

# README

## DETAILS FOR ACCESSING DATA

### CONTACT PERSON (Corresponding Author)
C. Brock Kirwan
1001 KMBL, Brigham Young University, Provo, UT 84602
Email: [e-mail]
Phone: [phone]
Fax: [phone]
ORCID ID: 0000-003-0768-1446

## OVERVIEW

### PROJECT NAME
Limited Evidence for a Triple Dissociation in the Medial Temporal Lobe: an fMRI Recognition Memory Replication Study

### YEARS THAT PROJECT RAN
2020-2021

### BRIEF OVERVIEW OF EXPERIMENTAL TASKS

The present experiment aims to replicate two previous papers (cited below) in which authors present two analysis paths for a dataset in which participants underwent fMRI while performing a recognition memory test for old and new words. Both studies found activation in the hippocampus, with the first (Daselaar, Fleck, & Cabeza, 2006) demonstrating a distinction in hippocampus activation corresponding to true and perceived oldness of stimuli and the second (Daselaar, Fleck, Prince, & Cabeza, 2006) demonstrating that hippocampus activation reflects the subjective experience of the participant.

We replicated behavioral and MRI acquisition parameters reported in these two target articles with N=53 participants and focused fMRI analyses on regions of interest reported in those articles looking at fMRI activation for differences corresponding with true and perceived oldness and those associated with subjective memory experiences of recollection, familiarity, and novelty.

References:
(1) Daselaar, S. M., Fleck, M. S., & Cabeza, R. (2006). Triple dissociation in the medial temporal lobes: Recollection, familiarity, and novelty. J Neurophysiol, 96(4), 1902–1911. https://doi.org/10.1152/jn.01029.2005 
(2) Daselaar, S. M., Fleck, M. S., Prince, S. E., & Cabeza, R. (2006). The medial temporal lobe distinguishes old from new independently of consciousness. J Neurosci, 26(21), 5835–5839. https://doi.org/26/21/5835 [pii] 10.1523/JNEUROSCI.0258-06.2006

### DATASET CONTENTS
This dataset includes raw data from all scanned participants acquired by the Siemens Trio 3T MRI scanner (12-channel head coil), with each participant consisting of the following folders: /anat, /fmap, and /func. /anat includes structural imaging data obtained from scanning in the form of .nii.gz and .json files. /fmap includes field mapping data in the form of .nii.gz and .json files. /func includes functional imaging data obtained from scanning in the form of .nii.gz and .json files, along with event.tsv files for each run (total runs = 4). Data for a total of N=53 participants is included in the present dataset.

### INDEPENDENT VARIABLES
True vs Perceived Oldness: Mean activity (mean parameter estimates) for each individual trial in the anterior/posterior MTL regions were identified by true oldness and perceived novelty contrasts. These resulting values were entered into a logistic regression model with activations in the MTL regions set as independent variables.
Subjective Confidence: Mean activity for each individual trial from different MTL regions were identified and entered into a multiple regression model based on activations in different MTL regions (i.e., recollection-related activity, familiarity-related activity, and novelty-related activity) as independent variables.

### DEPENDENT VARIABLES
True vs Perceived Oldness: A binary variable reflecting whether participants correctly recognized an old item as old (hit) or incorrectly classified an old item as new (miss) were set as the dependent variable.
Subjective Confidence: 6-point oldness scale was entered as the dependent variable.

### CONTROL VARIABLES
N/A

### QUALITY ASSESSMENT OF DATA
Data were preprocessed, which included spatial motion correction and spatial normalization that was automatically generated by the fMRIPrep software. Following fMRIPrep preprocessing, functional data were scaled with a mean of 100 and blurred with an 8 mm FWHM Gaussian kernel to account for inter-subject anatomical variation. Analysis scripts are available here: https://osf.io/ctvsw/. Data was acquired for N=60 participants, with data from n=7 participants excluded for reasons of ineligibility (left-handedness, n=1), failure to comply with study procedures (n=2), excessive motion (n=3), and equipment error (n=1).

## METHODS

### STUDY PHASE
In our experimental task, participants completed a study phase in which they were presented with a randomized list of 120 real English words and 80 pseudo words at a rate of 2000 ms per item. A fixation cross was presented between words for a random time interval varying between 0-5500 ms, where participants indicated whether the stimulus presented was a word or pseudo word. They were not informed at this time that their memory for the words would be tested. After the completion of the study phase, researchers situated participants in the MRI scanner and obtained localizer, field map, and T1-weighted structural MRI scans before initiating the test phase of the experiment.

### TEST PHASE
During the test phase, a task paradigm was presented as four experimental runs lasting between 435-442 seconds. Participants saw an equal number of target stimuli (words shown during the study phase) and foil stimuli (novel words) at 60 words per run. Target and foil stimuli were presented in a randomized order at 3.4 seconds. Participants were asked to make judgments on whether the word was presented on the study list while the stimulus was displayed. Confidence ratings were collected for those judgments between true and perceived oldness of stimuli from 1 (lowest confidence) to 4 (highest confidence), with a prompt displayed for 1.7 seconds.

### PARTICIPANTS
Recruitment: To determine sample size, an a prior power analysis was done by extracting values from Figure 1 of (Daselaar, Fleck, Prince, et al., 2006) in the right hippocampus via Web Plot Digitizer, given that the region showed smaller differences. We computed main effects by averaging hits and misses, and CRs and FAs prior to SEM to SD conversion and averaging again. Resulting values were entered into g+power to estimate an effect size of 0.46, indicating that a sample of N=54 would achieve a power of 0.95 with an error probability of 0.05 (t(1,53)=1.67). Participants were recruited from the campus community and met MRI compliance screening requirements.
Exclusion: Non-native English speakers, history of drug use, previous psychiatric or neurologic diagnosis, or contra-indications for MRI (e.g., ferromagnetic implant).
Compensation: Participants were compensated for participation with a choice of $20, course credit, or a 3D-printed 1/4-scale model of their brains.

### APPARATUS
Localizer, field map, and T1-weighted structural MRI scans were obtained once the participants were situated in the scanner. MRI data were collected using a Siemens Trio 3T MRI scanner (12-channel head coil) and behavioral responses were collected using a four-key fiber-optic response cylinder (Current Designs, n.d.). Structural scanning was done at the beginning of the scan session (256 x 215 matrix, TR 1900 ms, TE 2.26 ms, FOV 250 x 218 mm, 176 slices, 1 mm slice thickness, 0 mm spacing) and functional scanning was done during all experimental runs (64 x 64 image matrix, TR 1800 ms, TE 31 ms, FOV 240 mm, 34 slices, 3.8 mm slice thickness). An MR-compatible LCD monitor displayed stimuli from the head of the bore, which participants viewed through a mirror mounted on the head coil. MRI data are available at: https://openneuro.org/datasets/ds004086.

### INITIAL SETUP
[See above under STUDY PHASE and TEST PHASE for procedures performed once the participant arrived.]

### TASK ORGANIZATION
Behavioral and imaging data were collected for each participant through the course of four (4) experimental runs. Behavioral data was used to create event.tsv files for each participant per run, indicating the onset, duration, trial type, stimuli response, correct answer, and reaction times of responses. Each experimental run lasted between 435-442 seconds, where participants saw an equal number of target stimuli (words shown in the study phase) and foil stimuli (novel words) at 60 words per run.

### TASK DETAILS
Stimuli were presented for 3.4 seconds, where participants were asked to make judgments indicating whether the word was presented on the study list while the stimulus was displayed. Confidence ratings were then collected for those judgments between true and perceived oldness of stimuli from 1 (lowest confidence) to 4 (highest confidence). Prompt for the confidence ratings was displayed for 1.7 seconds, with each trial separated by an inter-trial interval (ITI) consisting of a fixation cross with a randomly distributed duration of 0-5.4 seconds (mean ITI=2.7 seconds).

### ADDITIONAL DATA ACQUIRED
Behavioral data were identified as hits, misses, correct rejections (CRs), and false alarms (FAs). Hits indicated correct judgments of “old” for words that were actually old. Misses reflected incorrect judgments of “old” for words that were actually new. Correct rejections indicated correct judgments of “new” for new words, and false alarms represented incorrect judgments of “new” for old words.

### EXPERIMENTAL LOCATION
The study was performed in the MRI Research Facility at the Brigham Young University campus in Provo, UT.

### MISSING DATA
The following subjects may be missing data and/or are not included in analyses for the following reasons:
Sub-001: Ineligible; left-handedness
Sub-005: Failure to comply; completed only 10% of entries compared to other subjects
Sub-026: Excessive motion
Sub-034: Failure to comply; did not provide a response other than a “1” or none
Sub-050: Excessive motion
Sub-052: Excessive motion
Sub-056: Equipment error

### NOTES
Sub-054 restarted their testing and completed the study protocol in full in the latter session.