Weaving a story: Narrative formation over prolonged time scales engages social cognition and frontoparietal networks.

Forming narratives is of key importance to human experience, enabling one to render large amounts of information into relatively compacted stories for future retrieval, giving meaning to otherwise fragmented occurrences. The neural mechanisms that underlie coherent narrative construction of causally connected information over prolonged temporal periods are yet unclear. Participants in this fMRI study observed consecutive scenes from a full-length movie either in their original order, enabling causal inferences over time, or in reverse order, impeding a key component of coherent narratives-causal inference. In between scenes, we presented short periods of blank screens for examining post-encoding processing effects. Using multivariate pattern analysis (MVPA) followed by seed-base correlation analysis, we hypothesized that networks involved in online monitoring of incoming information on the one hand, and offline processing of previous occurrences on the other would differ between the groups. We found that despite the exposure to the same scenes, the chronological-order condition exhibited enhanced functional connectivity in frontoparietal regions associated with information integration and working memory. The reverse-order condition yielded offline, post-scene coactivation of neural networks involved in social cognition and particularly theory of mind and action comprehension. These findings shed light on offline processes of narrative construction efforts, highlighting the role of social cognition networks in seeking for narrative coherence.

Theta EEG neurofeedback promotes early consolidation of real life-like episodic memory.

Theta oscillations are believed to coordinate neuronal activity related to human cognition, especially for memory functions. Theta power during learning and retrieval has been found to correlate with memory performance success. Additionally, up-regulating theta oscillations during a post-encoding epoch crucial for memory consolidation was previously shown to benefit long-term memory for acquired motor sequences, pictures, and object-location associations. However, it remains to be determined whether such effects would be found for more ecological aspects of long-term episodic memory. Therefore, the current study assessed neurofeedback-based theta upregulation effects on movie memory. After viewing a 15-minute silent, narrative movie, participants engaged in neurofeedback-based theta/beta up-regulation, neurofeedback beta/theta up-regulation as an active control condition, or an unrelated passive control task. Memory was tested three times: once immediately after watching the movie (as baseline); 24 hours thereafter; and once again 1 week later. Memory performance 1 week after encoding was significantly enhanced in the theta/beta up-regulation group compared with the other groups. Additionally, changes in neurofeedback theta/beta ratio from baseline EEG recordings correlated with long-term memory gains in retrieving the movie's content. These findings highlight the relationship between post-learning theta oscillations and the consolidation of episodic memory for a naturalistic event.

Enhanced declarative memory in long-term mindfulness practitioners.

OBJECTIVES: Mindfulness meditation (MM) practice is considered to benefit physical and mental health. In particular, several studies have shown a beneficial effect of MM practice on memory performance. However, it is still not clear how long-term training affects long-term declarative memory. In this study we aimed to examine whether long-term MM training impacts declarative memory formation for diverse memoranda types, as well as the role of trait mindfulness, and the possible mediating role of anxiety. METHODS: We examined long-term memory performance in 23 experienced MM practitioners and 22 meditation-naïve age-matched individuals, by administering a variety of declarative memory tests, ranging from item recognition to narrative and autobiographical memory recollection and future projection. The participants also filled the Five Facet Mindfulness Questionnaire (FFMQ) and State-Trait Anxiety Inventory (STAI). RESULTS: Compared to the control group, long-term MM practitioners exhibited heightened memory performance for the picture recognition test and experienced enhanced vividness during autobiographic memory retrieval and future simulations. We also report a significant trait mindfulness and memory performance correlation, stemming exclusively from the Mm group. CONCLUSIONS: Our findings extend previous reports of the beneficial effect of a short-term MM training on memory performance, by showing the beneficial effect of long-term training on declarative memory. We also provide initial evidence that trait mindfulness is positively correlated with declarative memory performance, as a function of MM practice, and discuss these findings in light of the role of self-mode and cognitive diffusion, as well as attention and emotion.

Age-related functional connectivity along the hippocampal longitudinal axis.

Accumulated evidence points toward a long-axis functional division of the hippocampus, with its anterior part primarily associated with emotional processes and the posterior with navigation and cognition. It is yet unclear, however, how functional connectivity between areas along the hippocampal longitudinal axis and other brain regions differ, and how they are affected by age. Applying an anatomically driven general linear model-based functional connectivity analysis on a large database of resting-state fMRI data, we demonstrate that independent of age, the posterior hippocampus is functionally connected primarily with sensory and motor areas, the middle hippocampus with the default mode network, and the anterior with limbic and prefrontal regions. Along with an age-related disintegration of intra-hippocampal BOLD signal uniformity, the middle and posterior sub-regions exhibit mostly decreases in their functional connectivity with cortical regions, whereas the anterior hippocampus and ventral striatum appear to become more synchronized with age. These findings indicate that long-axis hippocampal areas are tuned to particular functional networks, which do not age in a unified manner.

The opportunity to choose enhances long-term episodic memory.

Episodic memory is typically studied under conditions that treat participants as passive agents. Here we sought to explore how actively engaging in ongoing naturalistic occurrences affects long-term episodic memory. Participants viewed 40 short movie clips that depicted a protagonist that conversed with the participants. In each clip, they were either offered the chance to (supposedly) determine the clip's continuation (active condition), or let the computer decide for them (passive condition). Participants returned either two days or one week after the experience to undergo a true/false memory test for the clips' details and a two-alternative recognition test for the choices made. Memory performance for both groups was superior for information and choices conveyed in the active vs. passive condition. These findings suggest that the sense of actively influencing the unfolding of events is beneficial to long-term memory of the experience at large, baring potential interventions in the fields of education and cognitive enhancement.

Previously rewarding environments enhance incidental memory formation.

Declarative memory performance is superior for items that were encoded in temporal proximity to reward delivery or expectancy. How reward-predicting contexts affect subsequent declarative memory formation in those contexts are, however, unknown. Using an ecological experimental setup in the form of a naturalistic driving simulator task, we examined the effect that previously rewarded environments may have on incidental memory formation. After driving in two distinct environments, one of which associated with monetary reward, participants drove again in the environments, which were embedded with unique images on billboards. A recognition test 24 h later demonstrated that incidental memory was superior for items presented in the reward-associated environment. These findings suggest that environmental cues imbued with incentive salience promote memory processes even in the absence of reward.

Taking action in the face of threat: neural synchronization predicts adaptive coping.

The ability to take action in the face of threat is highly diverse across individuals. What are the neural processes that determine individual differences in the ability to cope with danger? We hypothesized that the extent of synchronization between amygdala, striatum, and medial prefrontal cortex (mPFC) would predict successful active coping performance. To test this, we developed a novel computer task based on the principals of Sidman avoidance. Healthy human participants learned through trial and error to move a marker between virtual game board compartments once every 3 s to avoid mild shocks. Behaviorally, participants exhibited large individual differences. Strikingly, both amygdala-mPFC and caudate-mPFC coupling during active coping trials covaried with final active coping performance across participants. These findings indicate that synchronization between mPFC subregions, and both amygdala and caudate predicts whether individuals will achieve successful active coping performance by the end of training. Thus, successful performance of adaptive actions in the face of threat requires functional synchronization of a neural circuit consisting of mPFC, striatum, and amygdala. Malfunction in the crosstalk between these components might underlie anxiety symptoms and impair individuals' ability to actively cope under stress. This opens an array of possibilities for therapeutic targets for fear and anxiety disorders.

The episodic engram transformed: Time reduces retrieval-related brain activity but correlates it with memory accuracy.

We took snapshots of human brain activity with fMRI during retrieval of realistic episodic memory over several months. Three groups of participants were scanned during a memory test either hours, weeks, or months after viewing a documentary movie. High recognition accuracy after hours decreased after weeks and remained at similar levels after months. In contrast, BOLD activity in a retrieval-related set of brain areas during correctly remembered events was similar after hours and weeks but significantly declined after months. Despite this reduction, BOLD activity in retrieval-related regions was positively correlated with recognition accuracy only after months. Hippocampal engagement during retrieval remained similar over time during recall but decreased in recognition. Our results are in line with the hypothesis that hippocampus subserves retrieval of real-life episodic memory long after encoding, its engagement being dependent on retrieval demands. Furthermore, our findings suggest that over time episodic engrams are transformed into a parsimonious form capable of supporting accurate retrieval of the crux of events, arguably a critical goal of memory, with only minimal network activation.

Increasing the complexity of isolated musical chords benefits concurrent associative memory formation.

The effects of background music on learning and memory are inconsistent, partially due to the intrinsic complexity and diversity of music, as well as variability in music perception and preference. By stripping down musical harmony to its building blocks, namely discrete chords, we explored their effects on memory formation of unfamiliar word-image associations. Chords, defined as two or more simultaneously played notes, differ in the number of tones and inter-tone intervals, yielding varying degrees of harmonic complexity, which translate into a continuum of consonance to dissonance percepts. In the current study, participants heard four different types of musical chords (major, minor, medium complex, and high complex chords) while they learned new word-image pairs of a foreign language. One day later, their memory for the word-image pairs was tested, along with a chord rating session, in which they were required to assess the musical chords in terms of perceived valence, tension, and the extent to which the chords grabbed their attention. We found that musical chords containing dissonant elements were associated with higher memory performance for the word-image pairs compared with consonant chords. Moreover, tension positively mediated the relationship between roughness (a key feature of complexity) and memory, while valence negatively mediated this relationship. The reported findings are discussed in light of the effects that basic musical features have on tension and attention, in turn affecting cognitive processes of associative learning.

Looking beyond the laboratory: Exploring behavioral and eye-fixation patterns in individuals with severe mental illness during a real-life supermarket task.

Individuals with severe mental illnesses (SMI) often have difficulty performing daily activities that require intact executive functions, such as grocery shopping. Performance-based evaluations are valuable but lack the subjects' viewpoints during task performance. This study aims to combine performance-based observation and cognitive science methods to provide insights regarding real-life behavior and problem-solving in populations with SMI. In this correlational-research study, 42 participants (10 in the SMI group and 32 in the control group) performed the Test of Grocery Shopping Skills (TOGSS) while wearing an eye-tracking device. We hypothesized that patterns in task planning, task-time use, and attention allocation to written information relevant to the task would differ between the groups during the task. The results showed between-group differences in both TOGSS efficiency outcomes (time and redundancy), duration, and number of fixations. An eye-tracking pattern analysis determined between-group differences in scanning patterns of the grocery list but similarities in task planning. The selection process was found to be significantly more accurate and efficient for the control group than for the SMI group. Our findings suggest that a combination of perspectives allows us to better understand the behavior of SMI individuals in a regular daily task.

Mesmerizing memories: brain substrates of episodic memory suppression in posthypnotic amnesia.

Two groups of participants, one susceptible to posthypnotic amnesia (PHA) and the other not, viewed a movie. A week later, they underwent hypnosis in the fMRI scanner and received a suggestion to forget the movie details after hypnosis until receiving a reversal cue. The participants were tested twice for memory for the movie and for the context in which it was shown, under the posthypnotic suggestion and after its reversal, while their brain was scanned. The PHA group showed reduced memory for movie but not for context while under suggestion. Activity in occipital, temporal, and prefrontal areas differed among the groups, and, in the PHA group, between suggestion and reversal conditions. We propose that whereas some of these regions subserve retrieval of long-term episodic memory, others are involved in inhibiting retrieval, possibly already in a preretrieval monitoring stage. Similar mechanisms may also underlie other forms of functional amnesia.

A tradeoff between musical tension perception and declarative memory.

Successful formation of long-term declarative memory is influenced, among other things, by attention, emotion, and deviation from expectations. A unique form of expectation can be elicited through musical tension, evoked by the prolongation of certain musical progressions. We examined the effect that musical tension exerts on the formation of declarative memory, by composing three original music pieces that contained tension segments, achieved by delays in release from dominant to tonic harmonies. Music-evoked tension was validated using music information retrieval (MIR) analysis, as well as skin conductance response (SCR) measures. Indeed, tension-evoking musical excerpts were associated with heightened SCR, corroborated by increased subjective ratings of tension, as compared to neutral excerpts. In the main experiment, 50 participants listened to the three musical pieces while they were presented with unique images that were randomly assigned to four conditions: tension, tension-release, neutral music, and silence. One day later, their memory for the images was examined using a recognition test. We found that memory performance was enhanced for images presented during both neutral and tense music compared to silence. Moreover, we observed a tradeoff effect between post-experiment tension perception and memory, such that individuals who perceived musical tension as such displayed reduced memory performance for images encoded during musical tension, whereas tense music benefited memory for those with lower musical tension perception. Understanding the interrelations between musical components, which exert powerful and fundamental responses in humans, and cognitive faculties, may provide insights as to the basic features of memory formation.

Memory-directed acupuncture as a neuromodulatory treatment for PTSD: Theory, clinical model and case studies.

Posttraumatic stress disorder (PTSD) poses an ongoing challenge to society, to health systems, and to the trauma victims themselves. Today PTSD is often considered an incurable chronic problem that lacks effective treatment. While PTSD is closely related to memory, it also affects many physiological systems. PTSD is usually treated with medications and psychotherapy with moderate success, leaving a substantial proportion of patients with enduring distress and disability. Therefore, a search for better treatment options is vital. In this paper, we propose a model in which a conversation-based technique is integrated with bodily manipulation through acupuncture. This approach first emerged in clinical experience showing intriguing results from treating PTSD patients using acupuncture as a main strategy. Its theoretical foundations derive from the clinic and rely on contemporary neuroscience's understanding of memory consolidation and reconsolidation processes. Research shows that acupuncture can have potentially positive effects at three levels: (a) achieving a balance between sympathetic and parasympathetic neural activity; (b) reducing activation in the limbic system, hence inducing a calming effect; (c) reshaping the functional connectivity map within important and relevant cortical regions that encompass the default-mode network. We suggest that coupling traumatic memory retrieval leading to reconsolidation, combined with acupuncture, offers considerable potential for positive clinical improvement in patients with PTSD. This may explain the positive results of the described case studies and can pave the path for future advances in research and treatment in this field.

Individual differences in experienced and observational decision-making illuminate interactions between reinforcement learning and declarative memory.

Decision making can be shaped both by trial-and-error experiences and by memory of unique contextual information. Moreover, these types of information can be acquired either by means of active experience or by observing others behave in similar situations. The interactions between reinforcement learning parameters that inform decision updating and memory formation of declarative information in experienced and observational learning settings are, however, unknown. In the current study, participants took part in a probabilistic decision-making task involving situations that either yielded similar outcomes to those of an observed player or opposed them. By fitting alternative reinforcement learning models to each subject, we discerned participants who learned similarly from experience and observation from those who assigned different weights to learning signals from these two sources. Participants who assigned different weights to their own experience versus those of others displayed enhanced memory performance as well as subjective memory strength for episodes involving significant reward prospects. Conversely, memory performance of participants who did not prioritize their own experience over others did not seem to be influenced by reinforcement learning parameters. These findings demonstrate that interactions between implicit and explicit learning systems depend on the means by which individuals weigh relevant information conveyed via experience and observation.

In the eye of the beholder: internally driven uncertainty of danger recruits the amygdala and dorsomedial prefrontal cortex.

Interpretation of emotional context is a pivotal aspect of understanding social situations. A critical component of this process is assessment of danger levels in the surrounding, which may have a direct effect on the organism's survival. The limbic system has been implicated in mediating this assessment. In situations of uncertainty, the evaluation process may also call for greater involvement of prefrontal cortex for decision-making and planning of an appropriate behavioral response. In the following study, morphed face images depicting emotional expressions were used to examine brain correlates of subjective uncertainty and perceptual ambiguity regarding danger. Fear and neutral expressions of 20 faces were morphed, and each of the face videos was divided into three sequences of equal length representing three levels of objective certainty regarding the expressions neutral, fear, and ambiguous. Sixteen subjects were scanned in a 1.5-T scanner while viewing 60 x 6-sec video sequences and were asked to report their subjective certainty regarding the level of danger surrounding the face on a four-level scale combining definite/maybe and danger/no-danger values. The individual responses were recorded and used as the basis for a "subjective protocol" versus an "objective protocol." Significant activations of the amygdala, dorsomedial prefrontal cortex, and dorsolateral prefrontal cortex were observed under the subjective protocol of internally driven uncertainty, but not under objective stimuli-based ambiguity. We suggest that this brain network is involved in generating subjective assessment of social affective cues. This study provides further support to the "relevance detector" theory of the amygdala and implicates its importance to behavior relying heavily on subjective assessment of danger, such as in the security domain context.

Subjective vs. documented reality: a case study of long-term real-life autobiographical memory.

A young woman was filmed during 2 d of her ordinary life. A few months and then again a few years later she was tested for the memory of her experiences in those days while undergoing fMRI scanning. As time passed, she came to accept more false details as true. After months, activity of a network considered to subserve autobiographical memory was correlated with memory confidence rather than with accuracy. After years, mainly regions of the temporal pole displayed this pattern. These results might reflect a slow process of increased reliance on schemata at the expense of accuracy.

Real-Life Neuroscience: An Ecological Approach to Brain and Behavior Research.

Owing to advances in neuroimaging technology, the past couple of decades have witnessed a surge of research on brain mechanisms that underlie human cognition. Despite the immense development in cognitive neuroscience, the vast majority of neuroimaging experiments examine isolated agents carrying out artificial tasks in sensory and socially deprived environments. Thus, the understanding of the mechanisms of various domains in cognitive neuroscience, including social cognition and episodic memory, is sorely lacking. Here we focus on social and memory research as representatives of cognitive functions and propose that mainstream, lab-based experimental designs in these fields suffer from two fundamental limitations, pertaining to person-dependent and situation-dependent factors. The person-dependent factor addresses the issue of limiting the active role of the participants in lab-based paradigms that may interfere with their sense of agency and embodiment. The situation-dependent factor addresses the issue of the artificial decontextualized environment in most available paradigms. Building on recent findings showing that real-life as opposed to controlled experimental paradigms involve different mechanisms, we argue that adopting a real-life approach may radically change our understanding of brain and behavior. Therefore, we advocate in favor of a paradigm shift toward a nonreductionist approach, exploiting portable technology in semicontrolled environments, to explore behavior in real life.

Bihemispheric leftward bias in a visuospatial attention-related network.

Asymmetry of spatial attention has long been described in both disease (hemispatial neglect) and healthy (pseudoneglect) states. Although right-hemisphere specialization for spatial attention has been suggested, the exact neural mechanisms of asymmetry have not been deciphered yet. A recent functional magnetic resonance imaging study from our laboratory serendipitously revealed bihemispheric left-hemifield superiority in activation of a visuospatial attention-related network. Nineteen right-handed healthy adult females participated in two experiments of visual half-field presentation. Either facial expressions (experiment 1) or house images (experiment 2) were presented unilaterally and parafoveally for 150 ms while subjects were engaging a central fixation task. Brain regions previously associated with a visuospatial attention network, in both hemispheres, were found to be more robustly activated by left visual field stimuli. The consistency of this finding with manifestations of attention lateralization is discussed, and a revised model based on neural connectivity asymmetry is proposed. Support for the revised model is given by a dynamic causal modeling analysis. Unraveling the basis for attention asymmetry may lead to better understanding of the pathogenesis of attention disorders, followed by improved diagnosis and treatment. Additionally, the proposed model for asymmetry of visuospatial attention might provide important insights into the mechanisms underlying functional brain lateralization in general.

Feedback Timing Modulates Probabilistic Learning in Adults with ADHD.

Attention deficit hyperactivity disorder (ADHD) has been associated primarily with executive function deficits. Emerging findings suggest, however, that procedural learning may be compromised as well. To this effect, we recently showed that feedback-based procedural learning is selectively impaired in ADHD, results that coincide with dopaminergic alterations associated with ADHD. Key questions, however, remain unresolved, among which are the learning conditions that may improve procedural learning in ADHD. Here we examined feedback-based probabilistic learning during conditions that engage procedural and declarative learning systems to different degrees, depending on feedback timing. ADHD and control participants carried out a probabilistic learning task in which they were required to learn to associate between cues and outcomes, where outcomes were presented either immediately or with a short/long delays. Whereas performance in probabilistic learning in ADHD participants was comparable to controls in delayed feedback conditions, during both learning and test phases, their performance diminished when feedback was immediate. Furthermore, ADHD symptom severity was negatively correlated with the ability to learn from immediate feedback. These results suggest that feedback-based probabilistic learning can be improved in ADHD, provided appropriate conditions. By shifting the load from midbrain/striatal systems to declarative memory mechanisms, behavioral performance in ADHD populations can be remediated.

Knowledge acquisition is governed by striatal prediction errors.

Discrepancies between expectations and outcomes, or prediction errors, are central to trial-and-error learning based on reward and punishment, and their neurobiological basis is well characterized. It is not known, however, whether the same principles apply to declarative memory systems, such as those supporting semantic learning. Here, we demonstrate with fMRI that the brain parametrically encodes the degree to which new factual information violates expectations based on prior knowledge and beliefs-most prominently in the ventral striatum, and cortical regions supporting declarative memory encoding. These semantic prediction errors determine the extent to which information is incorporated into long-term memory, such that learning is superior when incoming information counters strong incorrect recollections, thereby eliciting large prediction errors. Paradoxically, by the same account, strong accurate recollections are more amenable to being supplanted by misinformation, engendering false memories. These findings highlight a commonality in brain mechanisms and computational rules that govern declarative and nondeclarative learning, traditionally deemed dissociable.