Lila Davachi

• New York University

Memory-derived predictions help us to anticipate incoming sensory evidence. A mismatch between prediction and evidence leads to a prediction error (PE). Previous research suggested that PEs enhance memory of the surprising events. Here, we systematically investigated the effect of PE on episodic memory in children (10–12 years old), younger adults...

In what ways are social evaluations of others interdependent with what we think they believe about us? In the current study, we were interested in how social feedback changes how we think about a potential romantic partner, as well as how often we think about them. We hypothesized that the mentalizing network would play a role in both of these proc...

Dysfunction in emotion regulation (ER) and autobiographical memory are components of major depressive disorder (MDD). However, little is known about how they mechanistically interact with mood disturbances in real time. Using machine learning-based neural signatures, we can quantify negative affect (NA), ER, and memory continuously to evaluate how...

In everyday life, our perceptions of others’ traits are influenced by a combination of their actions and our relationship with them. We enrolled 142 participants in a virtual escape room to examine (a) whether an unfamiliar task changed perceptions of friends’ traits, (b) which types of prior relationships influenced trait perceptions, and (c) the...

While motivation typically enhances memory, some studies show that, in certain contexts, motivation associated with rewards can impair memory. Goal states associated with motivation can impact attention, which in turn influences what information is encoded and later remembered. There is limited research on how different incentive contexts, which ma...

In everyday life, our perceptions of others’ traits are influenced by a combination of their actions and our relationship with them. We enrolled 142 participants in a virtual escape room to examine a) whether an unfamiliar task changed perceptions of friends’ traits, b) which types of prior relationships influenced trait perceptions, and c) the rel...

Adaptively updating memories about familiar others is an important social skill. Here, we examined whether strong or weak social memories are more prone to updating when violated. Participants viewed well-known characters’ emotional reactions to food items either repeatedly or only once. They then studied new events where some characters exhibited...

Systems consolidation theories propose two mechanisms that enable the behavioral integration of related memories: coordinated reactivation between hippocampus and cortex, and the emergence of cortical traces that reflect overlap across memories. However, there is limited empirical evidence that links these mechanisms to the emergence of behavioral...

Every day, we encounter far more information than we could possibly remember. Thus, our memory systems must organize and prioritize the details from an experience that can adaptively guide the storage and retrieval of specific episodic events. Prior work has shown that shifts in internal goal states can function as event boundaries, chunking experi...

Although the role of the medial temporal lobe (MTL) and the hippocampus in episodic memory is well established, there is emerging evidence that these regions play a broader role in cognition, specifically in temporal processing. However, despite strong evidence that the hippocampus plays a critical role in sequential processing, the involvement of...

No sooner is an experience over than its neural representation begins to be transformed through memory reactivation during offline periods. The lion’s share of prior research has focused on understanding offline reactivation within the hippocampus. However, it is hypothesized that consolidation processes involve offline reactivation in cortical reg...

Memories reflect the ebb and flow of experiences, capturing unique and meaningful events from our lives. Using a combination of functional magnetic resonance imaging (fMRI), neuromelanin imaging, and pupillometry, we show that arousal and locus coeruleus (LC) activation transform otherwise continuous experiences into distinct episodic memories. As...

The Oxford Handbook of Human Memory covers the science of human memory, its application to clinical disorders, and its broader implications for learning and memory in real-world contexts. Written by field leaders, the handbook integrates behavioral, neural, and computational evidence with current theories of how humans learn and remember. Following...

Consolidating memories for long-term storage depends on reactivation. Reactivation occurs both consciously, during wakefulness, and unconsciously, during wakefulness and sleep. While considerable work has examined conscious awake and unconscious sleep reactivation, in this study, we directly compare the consequences of conscious and unconscious rea...

In everyday life, our pre-existing relationships influence our perceptions of others’ traits and actions. We enrolled 142 participants in a virtual escape room to examine a) whether a novel challenge changed perceptions of friends’ traits, b) how prior relationships influenced trait perceptions, and c) how prior relationships biased perceptions of...

Every day, we encounter far more information than we could possibly remember. Thus, our memory systems must organize and prioritize the details from an experience that can adaptively guide the storage and retrieval of specific episodic events. Prior work has shown that shifts in internal goal states can function as event boundaries, chunking experi...

Everyday life is composed of events organized by changes in contexts, with each event containing an unfolding sequence of occurrences. A major challenge facing our memory systems is how to integrate sequential occurrences within events while also maintaining their details and avoiding over-integration across different contexts. We asked if and how...

The ability to store information about the past to dynamically predict and prepare for the future is among the most fundamental tasks the brain performs. To date, the problems of understanding how the brain stores and organizes information about the past (memory) and how the brain represents and processes temporal information for adaptive behavior...

Pattern separation and pattern completion are opposing yet complementary components of mnemonic processing that heavily rely on the hippocampus. It has been shown that processing within the dentate gyrus (DG) subfield promotes pattern separation while operations within the CA3 subfield are important for pattern completion. Schizophrenia has been as...

Our brains constantly generate predictions about the environment based on prior knowledge. Many of the events we experience are consistent with these predictions, while others might be inconsistent with prior knowledge and thus violate our predictions. To guide future behavior, the memory system must be able to strengthen, transform, or add to exis...

Newly formed memories are not passively stored for future retrieval; rather, they are reactivated offline and thereby strengthened and transformed. However, reactivation is not a uniform process: it occurs throughout different states of consciousness, including conscious rehearsal during wakefulness and unconscious processing during both wakefulnes...

The transformation of experiences into meaningful events and memories is intertwined with the notion of time. Temporal perception can influence, and be influenced by, segmenting continuous experience into meaningful events. Episodic memories formed from these events become associated with temporal information as well. However, it is less clear how...

Throughout our lives, the actions we produce are often highly familiar and repetitive (e.g., commuting to work). However, layered upon these routine actions are novel, episodic experiences. Substantial research has shown that prior knowledge can facilitate learning of conceptually related new information. But despite the central role our behavior p...

Pattern separation, or the process by which highly similar stimuli or experiences in memory are represented by non-overlapping neural ensembles, has typically been ascribed to processes supported by the hippocampus. Converging evidence from a wide range of studies, however, suggests that pattern separation is a multistage process supported by a net...

To address the memory functioning after medial temporal lobe (MTL) surgery for refractory epilepsy and relationships with the side of the hippocampal removal, 22 patients with pharmaco‐resistant epilepsy who had undergone MTL resection (10 right/12 left) at the Salpêtrière Hospital were compared with 21 matched healthy controls. We designed a speci...

No sooner is an experience over than its neural memory representation begins to be strengthened and transformed through the process of memory replay. Using fMRI, we examined how memory strength manipulated through repetition during encoding modulates post-encoding replay in humans. Results revealed that repetition did not increase replay frequency...

Our experience of time can feel dilated or compressed, rather than reflecting true “clock time.” Although many contextual factors influence the subjective perception of time, it is unclear how memory accessibility plays a role in constructing our experience of and memory for time. Here, we used a combination of behavioral and functional MRI measure...

Systems consolidation theories propose two mechanisms that enable the behavioral integration of related memories: coordinated reactivation between hippocampus and cortex, and the emergence of cortical traces that reflect overlap across memories. However, there is limited empirical evidence that links these mechanisms to the emergence of behavioral...

A particularly elusive puzzle concerning the hippocampus is how the structural differences along its long, anteroposterior axis might beget meaningful functional differences, particularly in terms of the granularity of information processing. One measure posits to quantify this granularity by calculating the average statistical independence of the...

Reward motivation enhances memory through interactions between mesolimbic, hippocampal, and cortical systems - both during and after encoding. Developmental changes in these distributed neural circuits may lead to age-related differences in reward-motivated memory and the underlying neural mechanisms. Converging evidence from cross-species studies...

The long-term fate of a memory is not exclusively determined by the events occurring at the moment of encoding. Research at the cellular, circuit, and behavioral levels is beginning to reveal how neurochemical activations in the moments surrounding an event can retroactively and proactively rescue weak memory for seemingly mundane experiences. We r...

While our perceptual experience seems to unfold continuously over time, episodic memory preserves distinct events for storage and recollection. Previous work shows that stability in encoding context serves to temporally bind individual items into sequential composite events. This phenomenon has been almost exclusively studied using visual and spati...

Throughout our lives, the actions we produce can be highly familiar and repetitive (e.g., commuting to work); yet layered upon these routine actions are unique, one-shot, episodic experiences. Substantial research has shown that prior knowledge can facilitate learning of conceptually-related new information. However, despite the central role our be...

A particularly elusive puzzle concerning the hippocampus is how the structural differences along its long, anteroposterior axis might beget meaningful functional differences, particularly in terms of the granularity of information processing. One measure posits to quantify this granularity by calculating the average statistical independence of the...

The effects of aversive events on memory are complex and go beyond the simple enhancement of threatening stimuli in memory. Negative experiences can also rescue related but otherwise forgettable details encoded close in time. Here, we used functional magnetic resonance imaging (fMRI) in healthy young adults to examine the brain mechanisms that supp...

When our experience violates our predictions, it is adaptive to update our knowledge to promote a more accurate representation of the world and facilitate future predictions. Theoretical models propose that these mnemonic prediction errors should be encoded into a distinct memory trace to prevent interference with previous, conflicting memories. We...

Interictal epileptiform discharges (IEDs) can impair memory. The properties of IEDs most detrimental to memory, however, are undefined. We studied the impact of temporal and spatial characteristics of IEDs on list learning. Subjects completed a memory task during intracranial EEG recordings including hippocampal depth and temporal neocortical subdu...

Reward motivation enhances memory through interactions between mesolimbic, hippocampal, and cortical systems — both during and after encoding. Developmental changes in these distributed neural circuits may lead to age-related differences in reward-motivated memory and the underlying neural mechanisms. Converging evidence from cross-species studies...

Research has shown that sleep is beneficial for the long-term retention of memories. According to theories of memory consolidation, memories are gradually reorganized, becoming supported by widespread, distributed cortical networks, particularly during postencoding periods of sleep. However, the effects of sleep on the organization of memories in t...

Time unfolds continuously, yet our memories are stored as discrete episodes. Prior work shows that fluctuations between stability and change in an ongoing neutral context facilitates this formation of distinct and memorable events. However, less is known about how shifting emotional states influence these memory processes, despite ample evidence th...

Our experience of time can feel dilated or compressed, rather than reflecting true “clock time.” Although many contextual factors influence the subjective perception of time, it is unclear how memory accessibility plays a role in constructing our experience of and memory for time. Here, we used a combination of behavioral and fMRI measures to ask t...

Although life unfolds continuously, experiences are generally perceived and remembered as discrete events. Accumulating evidence suggests that event boundaries disrupt temporal representations and weaken memory associations. However, less is known about the consequences of event boundaries on temporal representations during retrieval, especially wh...

How does the brain process continuous experiences so they can be remembered? Evidence suggests that people perceive their experience as a series of distinct and meaningful events. Information encountered within the same event shows greater temporal integration in memory, as well as enhanced neural representational similarity. Although these data su...

When our experience violates our predictions, it is adaptive to update our knowledge to promote a more accurate representation of the world and facilitate future predictions. Theoretical models propose that these mnemonic prediction errors should be encoded into a distinct memory trace to prevent interference with previous, conflicting memories. We...

How do we evaluate whether someone will make a good friend or collaborative peer? A hallmark of human cognition is the ability to make adaptive decisions based on information garnered from limited prior experiences. Using an interactive social task measuring adaptive choice (deciding who to reengage or avoid) in male and female participants, we fin...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Episodic memory retrieval is increasingly influenced by schematic information as memories mature, but it is unclear whether this is due to the slow formation of schemas over time, or the slow forgetting of the episodes. To address this, we separately probed memory for newly learned schemas as well as their influence on episodic memory decisions. In...

Everyday life unfolds continuously, yet we tend to remember past experiences as discrete event sequences or episodes. Although this phenomenon has been well documented, the neuromechanisms that support the transformation of continuous experience into distinct and memorable episodes remain unknown. Here, we show that changes in context, or event bou...

When our experience violates our predictions, it is adaptive to upregulate encoding of novel information, while down-weighting retrieval of erroneous memory predictions to promote an updated representation of the world. We asked whether mnemonic prediction errors promote hippocampal encoding versus retrieval states, as marked by distinct network co...

The selective effects of emotion on memory go beyond the simple enhancement of threatening or rewarding stimuli. They can also rescue otherwise forgettable memories that share overlapping features. Here, we use functional magnetic resonance imaging (fMRI) to examine the brain mechanisms that support this retrograde memory enhancement. In a two-phas...

Here we examine the variability underlying successful memory encoding. Successful encoding of successive study items may fatigue encoding resources, thus decreasing the ability to encode subsequent items (Tulving and Rosenbaum, 2006); alternatively, successful encoding may be persistent, leading to more successful encoding (Kahana, Aggarwal, and Ph...

Episodic memory retrieval is increasingly influenced by schematic information as memories mature, but it is unclear whether this is due to the slow formation of schemas over time, or the slow decay of the episodes. To address this, we separately probed memory for newly learned schemas as well as their influence on episodic memory decisions. In this...

Memory consolidation is hypothesized to involve the distribution and restructuring of memory representations across hippocampal and cortical regions. Theories suggest that, through extended hippocampal-cortical interactions, cortical ensembles come to represent more integrated, or overlapping, memory traces that prioritize commonalities across rela...

Everyday life unfolds continuously, yet we tend to remember past experiences as discrete event sequences or episodes. Although this phenomenon has been well documented, the brain mechanisms that support the transformation of continuous experience into memorable episodes remain unknown. Here we show that a sudden change in context, or event boundary...

The ability for individuals to actively make decisions engages regions within the mesolimbic system and enhances memory for chosen items. In other behavioral contexts, mesolimbic engagement has been shown to enhance episodic memory by supporting consolidation. However, research has yet to investigate how consolidation may support interactions betwe...

Background: Converging evidence implicates the anterior hippocampus in the proximal pathophysiology of schizophrenia. Although resting state functional connectivity (FC) holds promise for characterizing anterior hippocampal circuit abnormalities and their relationship to treatment response, this technique has not yet been used in first-episode psy...

In situations when our experience violates our predictions, it is adaptive to upregulate encoding of novel information, while down-weighting retrieval of erroneous memory predictions to promote an updated representation of the world. We asked whether mnemonic prediction errors promote distinct hippocampal processing 'states' by leveraging recent re...

After experiences are encoded into memory, post-encoding reactivation mechanisms have been proposed to mediate long-term memory stabilization and transformation. Spontaneous reactivation of hippocampal representations, together with hippocampal-cortical interactions, are leading candidate mechanisms for promoting systems-level memory strengthening...

Our daily lives unfold continuously, yet when we reflect on the past, we remember those experiences as distinct and cohesive events. To understand this phenomenon, early investigations focused on how and when individuals perceive natural breakpoints, or boundaries, in ongoing experience. More recent research has examined how these boundaries modula...

Direct recordings from the human brain have historically involved epilepsy patients undergoing invasive electroencephalography (iEEG) for surgery. However, these measurements are temporally limited and affected by clinical variables. The RNS System (NeuroPace, Inc.) is a chronic, closed-loop electrographic seizure detection and stimulation system....

The ability to generalize from and distinguish between aversive memories and novel experiences is critical to survival. Previous research has revealed mechanisms underlying generalization of threat-conditioned defensive responses, but little is known about generalization of episodic memory for threatening events. Here we tested if aversive learning...

Acute stress can modulate memory for individual parts of an event (items), but whether it similarly influences memory for associations between items remains unclear. We used a within-subjects design to explore the influence of acute stress on item and associative memory in humans. Participants associated negative words with neutral objects, rated t...

It is well known that distributing study events over time leads to better memory over long time scales, compared with massing study events together. One explanation for such long-term resistance to forgetting is that distributed study leads to neural differentiation in memory, which supports retrieval of past experiences by disambiguating highly si...

Significance One of the biggest computational challenges the memory system faces is to disambiguate highly similar experiences while at the same time preserving and reinstating prior memories. Remarkably, hippocampal processes have been implicated in both of these functions. However, how this is accomplished is unknown. Leveraging the spatiotempora...

The ability for individuals to actively make decisions engages regions within the mesolimbic system and enhances memory for chosen items. In other behavioral contexts, mesolimbic engagement has been shown to enhance episodic memory by supporting consolidation. However, research has yet to investigate how consolidation may support interactions betwe...

Fear memories are characterized by their permanence and a fierce resistance to unlearning by new experiences. We considered whether this durability involves a process of memory segmentation that separates competing experiences. To address this question, we used an emotional-learning task designed to measure recognition memory for category exemplars...

Some patients with medically refractory focal epilepsy are chronically implanted with a brain-responsive neurostimulation device (the RNS ® System), permitting neurophysiological measurements at millisecond resolution. This clinical device can be adapted to measure hippocampal dynamics time-locked to cognitive tasks. We illustrate the technique wit...

Episodic memories are not veridical records of our lives, but rather are better described as organized summaries of experience. Theories and empirical research suggest that shifts in perceptual, temporal, and semantic information lead to a chunking of our continuous experiences into segments, or “events.” However, the consequences of these contextu...

Reactivation of representations corresponding to recent experience is thought to be a critical mechanism supporting long-term memory stabilization. Targeted memory reactivation, or the re-exposure of recently learned cues, seeks to induce reactivation and has been shown to benefit later memory when it takes place during sleep. However, despite rece...

Episodic memories are not veridical records of our lives, but rather are better described as organizedsummaries of experience. Theories and empirical research suggest that shifts in perceptual, temporal, andsemantic information lead to a chunking of our continuous experiences into segments, or “events.”However, the consequences of these contextual...

Although everyday experiences unfold continuously over time, shifts in context, or event boundaries, can influence how those events come to be represented in memory [1-4]. Specifically, mnemonic binding across sequential representations is more challenging at context shifts, such that successful temporal associations are more likely to be formed wi...

Reactivation of representations corresponding to recent experience is thought to be a critical mechanism supporting long-term memory stabilization. Targeted memory reactivation, or the re-exposure of recently learned cues, seeks to induce reactivation and has been shown to benefit later memory when it takes place during sleep. However, despite rece...

Mnemonic decision-making has long been hypothesized to rely on hippocampal dynamics that bias memory processing toward the formation of new memories or the retrieval of old ones. Successful memory encoding would be best optimized by pattern separation, whereby two highly similar experiences can be represented by underlying neural populations in an...

Structured knowledge is thought to form, in part, through the extraction and representation of regularities across overlapping experiences. However, little is known about how consolidation processes may transform novel episodic memories to reflect such regularities. In a multi-day fMRI study, participants encoded trial-unique associations that shar...

Reward motivation has been demonstrated to enhance declarative memory by facilitating systems-level consolidation. Although highreward information is often intermixed with lower reward information during an experience, memory for high value information is prioritized. How is this selectivity achieved? One possibility is that postencoding consolidat...

Emotional arousal can produce lasting, vivid memories for emotional experiences, but little is known about whether emotion can prospectively enhance memory formation for temporally distant information. One mechanism that may support prospective memory enhancements is the carry-over of emotional brain states that influence subsequent neutral experie...

The meaning we derive from our experiences is not a simple static extraction of the elements but is largely based on the order in which those elements occur. Models propose that sequence encoding is supported by interactions between high- and low-frequency oscillations, such that elements within an experience are represented by neural cell assembli...

Remembering the order in which events occur is a fundamental component of episodic memory. However, the neural mechanisms supporting serial recall remain unclear. Behaviorally, serial recall is greater for information encountered within the same event compared to across event boundaries, raising the possibility that contextual stability may modulat...

According to current models of episodic memory, the hippocampus binds together the neural representation of an experience during encoding such that it can be reinstated in cortex during subsequent retrieval. However, direct evidence linking hippocampal engagement during encoding with subsequent cortical reinstatement during retrieval is lacking. In...

After encoding, memories undergo a process of consolidation that determines long-term retention. For conditioned fear, animal models postulate that consolidation involves reactivations of neuronal assemblies supporting fear learning during postlearning “offline” periods. However, no human studies to date have investigated such processes, particular...