Biology subjects

Bainbridge, W. A.

Publications and source records attributed to Bainbridge, W. A..

16 recordsLinked to original sources

bioRxiv2026

Brain Decoding from a Deep Neural Network of Visual Memory Reveals the Maturation Trajectory of Memory Systems across Ages 3-7

Memories from the first four years of life are largely inaccessible by adulthood, yet these early experiences profoundly shape cognition throughout development. Understanding this phenomenon of infantile amnesia is critical for revealing the mechanisms of early memory development. Here, we developed a new content-based behavioral measure of memory that quantifies how closely children's memory patterns resemble those of adults, which we term the memory maturation score. Using a movie-watching fMRI dataset spanning age 3 to adulthood, we trained a cross-validated model on adults' movie-evoked brain activity to predict adult's propensity to remember each movie snippet, estimated by ResMem, a deep neural network trained to predict visual memorability. We then applied the model to each child's brain activity while viewing the same movie to assess their memory maturation (i.e., cross-decodability from adult patterns). Children exhibited adult-like neural patterns of memory around age 4, extending prior behavioral findings. Structural analyses showed that the volume of the left posterior hippocampus, but not age or total brain volume, significantly predicted children's memory maturation. Memory maturation around age 4 thus likely reflects age-related neural development of hippocampal memory systems, rather than an age increase itself. Functional searchlight analyses revealed a trajectory of memory maturation: the inferior temporal gyrus reflected mature memory-related processing from age 3 onward, the left posterior hippocampus by age 5, and higher-order regions involved in social-affective processing and multimodal integration by age 7. Together, these findings suggest that hippocampal maturation between ages 3 and 5 drives the maturation of memory patterns.

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bioRxiv2025

Mental Imagery abilities affect visual working memory performance: evidence from aphantasic participants

Visual imagery refers to the mental generation of visual representations of stimuli, while visual working memory involves retaining visual information for a short period without external input. Due to the conceptual overlap between these two constructs, successful performance on visual working memory tasks may rely on the use of visual imagery to rehearse items during the retention interval. Consequently, individuals with aphantasia, who lack voluntary visual imagery, may experience difficulties with such tasks. However, prior research has suggested that some individuals with aphantasia might employ non-visual strategies to compensate for this deficit. In two experiments, we examined visual working memory performance in aphantasic and control participants across a range of stimulus types. In Experiment 1, participants completed a change localization task using color squares and complex fractals; in Experiment 2, stimuli included real words, phonologically valid pseudowords, and phonologically invalid pseudowords. Across both experiments, aphantasic participants demonstrated significantly impaired visual working memory compared to controls. Notably, their performance was equally impaired for stimuli that were easily verbalizable (i.e., colors and words) and those that were not (i.e., fractals and pseudowords). Furthermore, individual differences in visual imagery ability, as measured by the Vividness of Visual Imagery Questionnaire (VVIQ), significantly predicted working memory performance across all stimulus types. These findings provide direct evidence for the critical role of visual imagery in supporting visual working memory.

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bioRxiv2024

The Neural Underpinnings of Aphantasia: A Case Study of Identical Twins

Aphantasia is a condition characterized by reduced voluntary mental imagery. As this lack of mental imagery disrupts visual memory, understanding the nature of this condition can provide important insight into memory, perception, and imagery. Here, we leveraged the power of case studies to better characterize this condition by running a pair of identical twins, one with aphantasia and one without, through mental imagery tasks in an fMRI scanner. We identified objective, neural measures of aphantasia, finding less visual information in their memories which may be due to lower connectivity between frontoparietal and occipitotemporal lobes of the brain. However, despite this difference, we surprisingly found more visual information in the aphantasic twin's memory than anticipated, suggesting that aphantasia is a spectrum rather than a discrete condition.

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bioRxiv2024

Navigating Memorability Landscapes: Hyperbolic Geometry Reveals Hierarchical Structures in Object Concept Memory

Why are some object concepts (e.g., birds, cars, vegetables, etc.) more memorable than others? Prior studies have suggested that features (e.g., color, animacy, etc.) and typicality (e.g., robin vs. penguin) of object images influences the likelihood of being remembered. However, a complete understanding of object memorability remains elusive. In this study, we examine whether the geometric relationship between object concepts explains differences in their memorability. Specifically, we hypothesize that image concepts will be geometrically arranged in hierarchical structures and that memorability will be explained by a concepts depth in these hierarchical trees. To test this hypothesis, we construct a Hyperbolic representation space of object concepts (N=1,854) from the THINGS database (Hebart et al., 2019), which consists of naturalistic images of concrete objects, and a space of 49 feature dimensions derived from data-driven models. Using ALBATROSS (Stier, A. J., Giusti, C., & Berman, M. G., In prep), a stochastic topological data analysis technique that detects underlying structures of data, we demonstrate that Hyperbolic geometry efficiently captures the hierarchical organization of object concepts above and beyond a traditional Euclidean geometry and that hierarchical organization is related to memorability. We find that concepts closer to the center of the representational space are more prototypical and also more memorable. Importantly, Hyperbolic distances are more predictive of memorability and prototypicality than Euclidean distances, suggesting that concept memorability and typicality are organized hierarchically. Taken together, our work presents a novel hierarchical representational structure of object concepts that explains memorability and typicality.

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bioRxiv2024

The Memorability of Voices is Predictable and Consistent across Listeners

Memorability, the likelihood that a stimulus is remembered, is an intrinsic stimulus property that is highly consistent across people--participants tend to remember and forget the same faces, objects, and more. However, these consistencies in memory have thus far only been observed for visual stimuli. We provide the first study of auditory memorability, collecting recognition memory scores from over 3000 participants listening to a sequence of different speakers saying the same sentence. We found significant consistency across participants in their memory for voice clips and for speakers across different utterances. Next, we tested regression models incorporating both low-level (e.g., fundamental frequency) and high-level (e.g., dialect) voice properties to predict their memorability. These models were significantly predictive, and cross-validated out-of-sample, supporting an inherent memorability of speakers voices. These results provide the first evidence that listeners are similar in the voices they remember, which can be reliably predicted by quantifiable voice features.

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bioRxiv2024

Drawings reveal changes in object memory, but not spatial memory, across time

Time has an immense influence on our memory. Truncated encoding leads to memory for only the gist of an image, and long delays before recall result in generalized memories with few details. Here, we used crowdsourced scoring of hundreds of drawings made from memory after variable encoding (Experiment 1) and retentions of that memory (Experiment 2) to quantify what features of memory content change across time. We found that whereas some features of memory are highly dependent on time, such as the proportion of objects recalled from a scene and false recall for objects not in the original image, spatial memory was highly accurate and relatively independent of time. We also found that we could predict which objects were recalled across time based on the location, meaning, and saliency of the objects. The differential impact of time on object and spatial memory supports a separation of these memory systems.

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bioRxiv2023

Learning Image Memorability with Feedback-Based Training

Memorability, or the likelihood that an image is later remembered, is an intrinsic stimulus property that is remarkably consistent across viewers. Despite this consistency in what people remember and forget, previous findings suggest a lack of consistency in what individuals subjectively believe to be memorable and forgettable. We aimed to improve the ability of participants to judge memorability using a feedback-based training paradigm containing face images (Experiment 1) or scene images (Experiment 2 and its replication and control experiments). Overall, participants were fairly accurate at categorizing the memorability of images. In response to the training, participants were able to improve their memorability judgments of scenes, but not faces. Those who used certain strategies to perform the task, namely relying on characteristic features of the scenes, showed greater learning. Although participants improved slightly over time, they never reached the level of ResMem, the leading DNN for estimating image memorability. These results suggest that with training, human participants can better their understanding of image memorability, but may be unable to access its full variance.

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bioRxiv2023

Diagnostic images for mild cognitive impairment reveal biomarker status and abnormal scene processing

Research on the impairment of episodic memory in Alzheimers disease often focuses on the processes of memory rather than the content of the specific images being remembered. We recently showed that patients with mild cognitive impairment (MCI), Stage 3 of Alzheimers disease, can memorize certain images quite well, suggesting that episodic memory is not uniformly impaired. Certain images, on the other hand, could not be memorized by MCI patients and were instead diagnostic for distinguishing MCI from healthy older adults. In this study, we investigate whether poor memory for diagnostic images is related to impaired neural processing in specific brain regions due to Alzheimers biomarker pathology. 64 healthy controls and 48 MCI participants in the DELCODE dataset performed a visual scene memory task during fMRI, with CSF Alzheimers disease biomarker data collected (i.e., amyloid and tau biomarkers). We found that diagnostic images have larger behavior-biomarker correlations for total tau, phospho-tau, A{beta}42/A{beta}40, A{beta}42/phospho-tau compared to non-diagnostic images, suggesting that memory for these specific images are more affected by Alzheimers disease pathology. The fMRI data revealed an interaction effect between group membership (healthy control / MCI) and image diagnosticity (diagnostic / non-diagnostic scene images), with MCI participants having higher activation in scene processing regions (parahippocampal place area, retrosplenial cortex and occipital place area) for diagnostic images than non-diagnostic images. In contrast, healthy controls showed no differences in processing between diagnostic and non-diagnostic images. These results suggest that MCI individuals may engage in inefficiently heightened encoding activation for these diagnostic images. Our results show that special "diagnostic" images exist that can reveal amyloid and tau pathology and differences in neural activity in scene regions.

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bioRxiv2022

Children Develop Adult-Like Visual Sensitivity to Image Memorability by the Age of Four

Adults have been shown to consistently remember and forget certain images despite large individual differences, suggesting a population-wide sensitivity to an images intrinsic memorability--a measure of how successfully an image is remembered. While a decade of research has focused on image memorability among adults, the developmental trajectory of these consistencies in memory is understudied. Here, we investigate by what age children gain adultlike sensitivity to the image memorability effect. We utilized data from Saragosa-Harris et al. (2021), where 137 children aged between 3 and 5 years old encoded animal-scene image pairs and then after a 5-minute, 24-hour, or 1-week delay performed a cued recognition task for each scene target given its animal cue. We tested adults memory of the same scene images using ResMem (Needell & Bainbridge, 2022), a pre-trained deep neural network that predicts adult image memorability scores, and using an online behavioral continuous recognition task (N = 116). Results showed that ResMem predictions, as a proxy of adults memory, predicted scene memory of children by the age of 4 and were the most predictive of childrens memory across ages after a long, 1-week delay. Children at age 3 show non-adult-like consistent memory patterns, implying that the non-adult-like memory patterns were not due to poor memory performance. Instead, 3-year-olds may have consistently used certain visual memory strategies that become less optimal as they age. Our results suggest that adult-like sensitivity to image memorability emerges by the age of 4 through experience. Public Significance StatementThis study strongly suggests that children older than 4 years old tend to remember and forget the same images as adults. We recommend teachers and caregivers to utilize the ResMem DNN to select memorable images to be used in educational settings.

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bioRxiv2022

Neural similarity between overlapping events at learning differentially affects reinstatement across the cortex

Episodic memory often involves high overlap between the actors, locations, and objects of everyday events. Under some circumstances, it may be beneficial to distinguish, or differentiate, neural representations of similar events to avoid interference at recall. Alternatively, forming overlapping representations of similar events, or integration, may aid recall by linking shared information between memories. It is currently unclear how the brain supports these seemingly conflicting functions of differentiation and integration. We used multivoxel pattern similarity analysis (MVPA) of fMRI data and neural-network analysis of visual similarity to examine how highly overlapping naturalistic events are encoded in patterns of cortical activity, and how the degree of differentiation versus integration at encoding affects later retrieval. Participants performed an episodic memory task in which they learned and recalled naturalistic video stimuli with high feature overlap. Visually similar videos were encoded in overlapping patterns of neural activity in temporal, parietal, and occipital regions, suggesting integration. We further found that encoding processes differentially predicted later reinstatement across the cortex. In visual processing regions in occipital cortex, greater differentiation at encoding predicted later reinstatement. Higher-level sensory processing regions in temporal and parietal lobes showed the opposite pattern, whereby highly integrated stimuli showed greater reinstatement. Moreover, integration in high-level sensory processing regions during encoding predicted greater accuracy and vividness at recall. These findings provide novel evidence that encoding-related differentiation and integration processes across the cortex have divergent effects on later recall of highly similar naturalistic events.

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bioRxiv2022

Multidimensional topography of memory revealed from thousands of daily documented memories

Our memories form a rich, colorful tapestry of emotions, events, people, and places, woven across the decades of our lives. However, research has typically been limited in its ability to assess the multidimensional nature of episodic memory, given the short time scales and artificial stimulus sets often required in experiments. In an era when people are constantly recording their lives through social media, we can now examine key questions about the behavioral and neural underpinnings of diverse and extensive real-world memories. Here, we tested the neural representations of episodic memory in a naturalistic setting, specifically focusing on the age, location, subjective memory strength, and emotional content of memories. We recruited 23 users of a video diary app ("1 Second Everyday"), who had recorded a total of 9,266 daily memory videos spanning up to 7 years prior to our study. During a 3T fMRI scan, participants viewed a set of 300 of their own memory videos intermixed with 300 videos from another individual. We identified key areas specifically engaged for ones own memories versus anothers. Delving into the multidimensional nature of these memories, we find that their features are tightly interrelated, highlighting the need to consider these features in conjunction when conducting memory research. Importantly, when looking at the distinct contributions of these features, we find a topography of memory content extending across the medial parietal lobe with separate representations of a memorys age, its strength, and the familiarity of the people and places involved.

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bioRxiv2022

The Features Underlying the Memorability of Objects

What makes certain images more memorable than others? While much of memory research has focused on participant effects, recent studies employing a stimulus-centric perspective have sparked debate on the determinants of memory, including the roles of semantic and visual features and whether the most prototypical or atypical items are best remembered. Prior studies have typically relied on constrained stimulus sets, limiting a generalized view of the features underlying what we remember. Here, we collected 1+ million memory ratings for a naturalistic dataset of 26,107 object images designed to comprehensively sample concrete objects. We establish a model of object features that is predictive of image memorability and examined whether memorability could be accounted for by the typicality of the objects. We find that semantic features exert a stronger influence than perceptual features on what we remember and that the relationship between memorability and typicality is more complex than a simple positive or negative association alone. TEASERSemantic versus perceptual features more heavily influence what we remember, and memorability cannot be reduced to typicality.

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bioRxiv2020

Disrupted object-scene semantics boost scene recall but diminish object recall in drawings from memory

Humans are highly sensitive to the statistical relationships between features and objects within visual scenes. Inconsistent objects within scenes (e.g., a mailbox in a bedroom) instantly jump out to us, and are known to capture our attention. However, it is debated whether such semantic inconsistencies result in boosted memory for the scene, impaired memory, or have no influence on memory. Here, we examined the relationship of scene-object consistencies on memory representations measured through drawings made during recall. Participants (N=30) were eye-tracked while studying 12 real-world scene images with an added object that was either semantically consistent or inconsistent. After a 6-minute distractor task, they drew the scenes from memory while pen movements were tracked electronically. Online scorers (N=1,725) rated each drawing for diagnosticity, object detail, spatial detail, and memory errors. Inconsistent scenes were recalled more frequently, but contained less object detail. Further, inconsistent objects elicited more errors reflecting looser memory binding (e.g., migration across images). These results point to a dual effect in memory of boosted global (scene) but diminished local (object) information. Finally, we replicated prior effects showing that inconsistent objects captured eye fixations, but found that fixations during study were not correlated with recall performance, time, or drawing order. In sum, these results show a nuanced effect of scene inconsistencies on memory detail during recall.

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bioRxiv2019

Quantifying Aphantasia through drawing: Those without visual imagery show deficits in object but not spatial memory

Congenital aphantasia is a recently characterized experience defined by the inability to form voluntary visual imagery, in spite of intact semantic memory, recognition memory, and visual perception. Because of this specific deficit to visual imagery, aphantasia serves as an ideal population for probing the nature of representations in visual memory, particularly the interplay of object, spatial, and symbolic information. Here, we conducted a large-scale online study of aphantasics and revealed a dissociation in object and spatial content in their memory representations. Sixty-one aphantasics and matched controls with typical imagery studied real-world scene images, and were asked to draw them from memory, and then later copy them during a matched perceptual condition. Drawings were objectively quantified by 2,795 online scorers for object and spatial details. Aphantasics recalled significantly fewer objects than controls, with less color in their drawings, and an increased reliance on verbal scaffolding. However, aphantasics showed incredibly high spatial accuracy, equivalent to controls, and made significantly fewer memory errors. These differences between groups only manifested during recall, with no differences between groups during the matched perceptual condition. This object-specific memory impairment in aphantasics provides evidence for separate systems in memory that support object versus spatial information.

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bioRxiv2019

Distinct representational structure and spatial distribution for visual encoding and recall

During memory recall and visual imagery, reinstatement is thought to occur as an echoing of the neural patterns during encoding. However, the precise information in these recall traces is relatively unknown, with previous work primarily investigating either broad distinctions or specific images, rarely bridging these levels of information. Using ultra-high-field (7T) fMRI with an item-based visual recall task, we conducted an in-depth comparison of encoding and recall along a spectrum of granularity, from coarse (scenes, objects) to mid (e.g., natural, manmade scenes) to fine (e.g., living room, cupcake) levels. In the scanner, participants viewed a trial-unique item, and after a distractor task, visually imagined the initial item. During encoding, we observed decodable information at all levels of granularity in category-selective visual cortex. In contrast, information during recall was primarily at the coarse level with fine level information in some areas; there was no evidence of mid-level information. A closer look revealed segregation between voxels showing the strongest effects during encoding and those during recall, and peaks of encoding-recall similarity extended anterior to category-selective cortex. Collectively, these results suggest visual recall is not merely a reactivation of encoding patterns, displaying a different representational structure and localization from encoding, despite some overlap.

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bioRxiv2019

Memorability of photographs in subjective cognitive decline and mild cognitive impairment: implications for cognitive assessment

INTRODUCTIONImpaired long-term memory is a defining feature of Mild Cognitive Impairment (MCI). We tested whether this impairment is item-specific, limited to some memoranda whereas some remain consistently memorable.\n\nMETHODSWe conducted item-based analyses of long-term visual recognition memory. 394 participants (healthy controls (HC), Subjective Cognitive Decline (SCD), and MCI) in the multicentric DZNE-Longitudinal Cognitive Impairment and Dementia Study (DELCODE) were tested with images from a pool of 835 photographs.\n\nRESULTSWe observed consistent memorability for images in HCs, SCDs, and MCI, predictable by a neural network trained on another healthy sample. Looking at memorability differences between groups, we identified images that could successfully categorize group membership with higher success and a substantial image reduction than the original image set.\n\nDISCUSSIONIndividuals with SCD and MCI show consistent memorability for specific items, while other items show significant diagnosticity. Certain stimulus features could optimize diagnostic assessment, while others could support memory.

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