DOI: 10.5061/dryad.fbg79cp48
title: Data from: Hippocampal-occipital connectivity reflects autobiographical memory deficits in aphantasia

description: Aphantasia refers to reduced or absent visual imagery. While most of us
 can readily recall decade-old personal experiences (autobiographical
 memories, AM) with vivid mental images, there is a dearth of information
 about whether the loss of visual imagery in aphantasics affects their AM
 retrieval. The hippocampus is thought to be a crucial hub in a brain-wide
 network underlying AM. One important question is whether this network,
 especially the connectivity of the hippocampus, is altered in aphantasia.
 In the current study, we tested 14 congenital aphantasics and 16
 demographically matched controls in an AM fMRI task to investigate how key
 brain regions (i.e., hippocampus and visual-perceptual cortices) interact
 with each other during AM re-experiencing. All participants were
 interviewed regarding their autobiographical memory to examine their
 episodic and semantic recall of specific events. Aphantasics reported more
 difficulties in recalling AM, were less confident about their memories,
 and described less internal and emotional details than controls. Neurally,
 aphantasics displayed decreased hippocampal and increased
 visual-perceptual cortex activation during AM retrieval compared to
 controls. In addition, controls showed strong negative functional
 connectivity between the hippocampus and the visual cortex during AM and
 resting-state functional connectivity between these two brain structures
 predicted better visualization skills. Our results indicate that visual
 mental imagery plays an important role in detail-rich vivid AM, and that
 this type of cognitive function is supported by the functional connection
 between the hippocampus and the visual-perceptual cortex.
description: # Data from: Hippocampal-occipital connectivity reflects autobiographical
 memory deficits in aphantasia
 [https://doi.org/10.5061/dryad.fbg79cp48](https://doi.org/10.5061/dryad.fbg79cp48) **The submitted Data.xlsx file contains the following contents:** 1\. Demographics 2\. Scores from Autobiographical Memory Interviews 3\. Behavioural data from fMRI paradigms 4\. Extracted signal intensities in native space 5\. Signal change of the peaks of activated voxels with 1 mm sphere 6\. Extracted functional connectivity **## Description of the data and file structure** **Demographics:** ID = The catalogue ID for the participants Age = The age of the participants, ranging from 18-85 (in years) Sex = The sex of the participants, categorised into M (male) and F (female) Group = The group of the participants, categorised into Aphantasia and Healthy Control Education = The years of education reported by the participants, ranging from 10-20 (in years) VVIQ = Vividness of Visual Imagery Questionnaire (in points) miniQ = Three minute reasoning test (in points) Binocular Rivalry Result = Priming score of the mental imagery binocular rivalry task (in %) Epi_Richness = Mean rating of episodic richness in the autobiographical interviews (in points) Visualization Score = Self-reported visualization score (in points) **Autobiographical interviews:** Recall_Ext_Event = details of external event during general probe (quantity) Recall_Semantic = semantic details during general probe (quantity) Recall_Repetition = details repetition during general probe (quantity) Recall_Other = other details (metacognitive statements, editorializing) during general probe (quantity) Recall_Place = details of place during general probe (quantity) Recall_Time = details of time during general probe (quantity) Recall_Int_Event = details of internal event during general probe (quantity) Recall_Perception = perceptual details during general probe (quantity) Recall_Emotion = details of emotion during general probe (quantity) Recall_Place_ratings = details of place scored by raters during general probe (quantity) Recall_Time_ratings = details of time scored by raters during general probe (quantity) Recall_Perception_ratings = perceptual details scored by raters during general probe (quantity) Recall_Emotion_ratings = details of emotion scored by raters during general probe (quantity) Recall_Episodic_richness_ratings = episodic richness scored by raters during general probe (quantity) Recall_Confidence_ratings = semantic details scored by raters during general probe (quantity) Recall_Time_integration = details of time integration scored by raters during general probe (quantity) Specific_Ext_Event = details of external event during specific probe (quantity) Specific_Semantic = semantic details during specific probe (quantity) Specific_Repetition = details repetition during specific probe (quantity) Specific_Other = other details (metacognitive statements, editorializing) during general probe (quantity) Specific_Place = details of place during specific probe (quantity) Specific_Time = details of time during specific probe (quantity) Specific_Int_Event = details of internal event during specific probe (quantity) Specific_Perception = perceptual details during specific probe (quantity) Specific_Emotion = details of emotion during specific probe (quantity) Specific_Place_ratings = details of place scored by raters during specific probe (quantity) Specific_Time_ratings = details of time scored by raters during specific probe (quantity) Specific_Perception_ratings = perceptual details scored by raters during specific probe (quantity) Specific_Emotion_ratings = details of emotion scored by raters during specific probe (quantity) Specific_Episodic_richness_ratings = episodic richness scored by raters during specific probe (quantity) Specific_Confidence_ratings = semantic details scored by raters during specific probe (quantity) Specific_Time_integration = details of time integration scored by raters during specific probe (quantity) **Behavioural:** AM = Autobiographical memory chosen during the task BL = arithmatic problems as baseline AM_Search_Time = amount of time it took to search for memory (in ms) AM_Stim_Length = the time length the stimulus was displayed during AM trials (in ms) AM_Trial_Length = the entire length of each trial including stimulus and question during AM trials (in ms) AM_Reponse_Length = the time length it took for a response button to be pressed during AM trials (in ms) BL_Search_Time = amount of time it took to calculate the arithmatic problems as baseline (in ms) BL_Stim_Length = the time length the stimulus was displayed during MA trials as baseline (in ms) BL_Trial_Length = the entire length of each trial including stimulus and question during MA trials as baseline (in ms) BL_Reponse_Length = the time length it took for a response button to be pressed during MA trials as baseline (in ms) AM_Vivid = the chosen memory is vivid (quantity) AM_Fainted = the chosen memory is fainted (quantity) AM_VividTotal = the amount of vividness answers (quantity) AM_VividMissing = the amount of missing vividness answers (quantity) BL_Easy = the arithmatic problem is easy to calculate (quantity) BL_Difficult = the arithmatic problem is difficult to calculate (quantity) BL_EasyTotal = the amount of difficulty answers (quantity) BL_EasyMissing = the amount of missing difficulty answers (quantity) AM_#Response = the number of response given during AM trials (quantity) AM_#Ela = the number of memory for elaboration given during AM trials (quantity) AM_ResponseTotal = the total number of response during AM trials (quantity) AM_ResponseMissing = the total number of missing response during AM trials (quantity) BL_#Response = the number of response given during MA trials as baseline (quantity) BL_#Ela = the total number of response during MA trials as baseline (quantity) BL_ResponseTotal = the total number of missing response during MA trials as baseline (quantity) BL_ResponseMissing = the total number of missing response during MA trials as baseline (quantity) NA = Missing data **Native_Signal_Intensities:** Native space = the original, untransformed space of the subject within the skull in which the fMRI data was acquired Signal Intensities = the extracted voxel-based intensity value representing the level of brain activity within the specific region HC = Hippocampus Ant HC = Anterior Hippocampus Post HC = Postterior Hippocampus **AM_Peak_1mm:** Peak = activation extracted from the peak voxel within the selected ROI with the highest signal intensity value 1 mm = the peak coordinate with a diameter of 1 millimeter V = visual cortex **Functional_Connectivity:** Aphan&gt; = Connectivity value extracted from regions in which the Aphantasics displayed stronger connectivity than the Controls Ctrl&gt; = Connectivity value extracted from regions in which the Controls displayed stronger connectivity than the Aphantasics AM+Visualization = functional connectivity in combination with self-reported visualization score during autobiographical memory task Resting-state+Visualization = functional connectivity in combination with self-reported visualization score during resting-state **## Sharing/Access information** We do not have ethical approval of our research institution and our participants to share the raw brain imaging data publically. We also hold the permission to share raw data with scientific collaborators (no commercial research), so that interested researchers may contact [cornelia.mccormick@dzne.de](mailto:cornelia.mccormick@dzne.de). There is no need for a research proposal. **## Code/Software** **Software used to analyse the data:** 1\. Matlab v2019a 2\. Statistical Parametric Mapping 12 (SPM12) 3\. ITKSnap v3.8 4\. Region of interest EXtraction (REX) toolbox 5\. Functional Connectivity toolbox (CONN) v20b 6\. Partial Least Squares (PLS) toolbox 7\. GraphPad Prism **Preprocessing Steps:** 1\. Images reorientation 2\. Calculate voxel displacement maps (VDM) 3\. Realignement and umwarping of time-series 4\. Segmentation and bias correction of T1 image 5\. Within subject images co-registration 6\. Images normalisation to standard MNI space 7\. Smoothing (to standard MNI images) of 8 mm Full width at half maximum (FWHM)