Semantic relatedness proactively benefits learning, memory, and interdependence across episodes.

Over the past century of memory research, the interplay between initial and later-learned information in determining long-term memory retention has been of central interest. A likely factor for determining whether initial and later memories interfere with or strengthen each other is semantic relatedness. Relatedness has been shown to boost initial memory and increase the interdependence between earlier and more recent experiences in memory.

Study While You Sleep: Using Targeted Memory Reactivation as an Independent Research Project for Undergraduates.

Newly acquired information is stabilized into long-term memory through the process of consolidation. Memories are not static; rather, they are constantly updated via reactivation, and this reactivation occurs preferentially during Slow-Wave Sleep (SWS, also referred to as N3 in humans). Here we present a scalable neuroscience research investigation of memory reactivation using low-cost electroencephalogram (EEG) recording hardware and open-source software, for students and educators across the K-12 and higher education spectrum.

Aversive memories can be weakened during human sleep via the reactivation of positive interfering memories.

Recollecting painful or traumatic experiences can be deeply troubling. Sleep may offer an opportunity to reduce such suffering. We developed a procedure to weaken older aversive memories by reactivating newer positive memories during sleep.

Memory out of context: Spacing effects and decontextualization in a computational model of the medial temporal lobe.

Some neural representations gradually change across multiple timescales. Here we argue that modeling this "drift" could help explain the spacing effect (the long-term benefit of distributed learning), whereby differences between stored and current temporal context activity patterns produce greater error-driven learning. We trained a neurobiologically realistic model of the entorhinal cortex and hippocampus to learn paired associates alongside temporal context vectors that drifted between learning episodes and/or before final retention intervals.

Building and Breaking the Chain: A Model of Reward Prediction Error Integration and Segmentation of Memory.

Prediction errors drive reinforcement learning and organize episodic memory into distinct contexts, but do these effects interact? Here, we review the roles of midbrain dopamine, the locus coeruleus, and the hippocampus in event cognition to propose and simulate the theoretical influence of two prediction error signals in integrating versus segmenting events in memory. We suggest that signed reward prediction errors can build mental models of reward environments, increasing the contextual similarity (integration) of experiences with stronger, more stable reward expectations. On the other hand, unsigned reward prediction errors can signal a new model of the environment, generating a contextual shift (segmentation) between experiences that crossed them.

Causal and Chronological Relationships Predict Memory Organization for Nonlinear Narratives.

While recounting an experience, one can employ multiple strategies to transition from one part to the next. For instance, if the event was learned out of linear order, one can recall events according to the time they were learned (temporal), similar events (semantic), events occurring nearby in time (chronological), or events produced by the current event (causal). To disentangle the importance of these factors, we had participants watch the nonlinear narrative, Memento, under different task instructions and presentation orders.

Memory Reactivation during Sleep Does Not Act Holistically on Object Memory.

Memory reactivation during sleep is thought to facilitate memory consolidation. Most sleep reactivation research has examined how reactivation of specific facts, objects, and associations benefits their overall retention. However, our memories are not unitary, and not all features of a memory persist in tandem over time.

Item-specific neural representations during human sleep support long-term memory.

Understanding how individual memories are reactivated during sleep is essential in theorizing memory consolidation. Here, we employed the targeted memory reactivation (TMR) paradigm to unobtrusively replaying auditory memory cues during human participants' slow-wave sleep (SWS). Using representational similarity analysis (RSA) on cue-elicited electroencephalogram (EEG), we found temporally segregated and functionally distinct item-specific neural representations: the early post-cue EEG activity (within 0 to 2,000 ms) contained comparable item-specific representations for memory cues and control cues, signifying effective processing of auditory cues.

Long-term, multi-event surprise correlates with enhanced autobiographical memory.

Neurobiological and psychological models of learning emphasize the importance of prediction errors (surprises) for memory formation. This relationship has been shown for individual momentary surprising events; however, it is less clear whether surprise that unfolds across multiple events and timescales is also linked with better memory of those events. We asked basketball fans about their most positive and negative autobiographical memories of individual plays, games and seasons, allowing surprise measurements spanning seconds, hours and months.

Reap while you sleep: Consolidation of memories differs by how they were sown.

Newly formed memories are spontaneously reactivated during sleep, leading to their strengthening. This reactivation process can be manipulated by reinstating learning-related stimuli during sleep, a technique termed targeted memory reactivation. Numerous studies have found that delivering cues during sleep improves memory for simple associations, in which one cue reactivates one tested memory.

Oesophagoscopy in a Treated Oral Cavity Carcinoma Patient: A Case Report and Review.

Vegetable matter, especially fruit seed impaction, is uncommon in Otolaryngology practice. If it happens, there should be a possibility of abnormality in the oesophagus like stricture, web, malignancy, trauma or diverticulum. Here we present a case of seed as a foreign body oesophagus in a patient who was a known case of carcinoma left buccal mucosa status post left hemimandibulectomy with flap reconstruction Radiotherapy 20 years ago.

Semantic associates create retroactive interference on an independent spatial memory task.

Semantic similarity between stimuli can lead to false memories and can also potentially cause retroactive interference (RI) for veridical memories. Here, participants first learned spatial locations for "critical" words that reliably produce false memories in the Deese-Roediger-McDermott paradigm. Next, participants centrally viewed words that were semantically associated with half of the critical words.

Targeted memory reactivation during sleep influences social bias as a function of slow-oscillation phase and delta power.

To understand how memories are reactivated and consolidated during sleep, experimenters have employed the unobtrusive re-presentation of memory cues from a variety of pre-sleep learning tasks. Using this procedure, known as targeted memory reactivation (TMR), we previously found that reactivation of counter-social-bias training during post-training sleep could selectively enhance training effects in reducing unintentional social biases. Here, we describe re-analyses of electroencephalographic (EEG) data from this previous study to characterize neurophysiological correlates of TMR-induced bias reduction.

Real-time, closed-loop, or open-loop stimulation? Navigating a terminological jungle.

Recent advancements in real-time brain stimulation in the sleep field have led to many exciting findings. However, they have also opened up terminological ambiguities about what constitutes "open-loop", "closed-loop", and "real-time" designs. Here, we address core theoretical aspects of these terms in the hopes of strengthening future research on this topic.

Real-time stimulation during sleep: prior findings, novel developments, and future perspectives.

Real-time brain stimulation is a powerful technique that continues to gain importance in the field of sleep and cognition. In this special issue, we collected 14 articles about real-time stimulation during sleep, including one review, 12 research articles and one letter covering both human and rodent research from various fields. We hope this special issue sparks greater interest and inspires fellow sleep researchers and clinicians to develop new ideas in the exciting topic of real-time stimulation.

Semantic relatedness retroactively boosts memory and promotes memory interdependence across episodes.

Two fundamental issues in memory research concern when later experiences strengthen or weaken initial memories and when the two memories become linked or remain independent. A promising candidate for explaining these issues is semantic relatedness. Here, across five paired-associate learning experiments (N=1000), we systematically varied the semantic relatedness between initial and later cues, initial and later targets, or both.

Spatial gist extraction during human memory consolidation.

Theories of memory consolidation suggest that initially rich, vivid memories become more gist-like over time. However, it is unclear whether gist-like representations reflect a loss of detail through degradation or the blending of experiences into statistical averages, and whether the strength of these representations increases, decreases, or remains stable over time. We report three behavioral experiments that address these questions by examining distributional learning during spatial navigation.

Paranoia in patients attending child and adolescent mental health services.

Objective: Paranoia may be particularly prevalent during adolescence, building on the heightened social vulnerabilities at this age. Excessive mistrust may be corrosive for adolescent social relationships, especially in the context of mental health disorders. We set out to examine the prevalence, symptom associations, and persistence of paranoia in a cohort of young people attending child and adolescent mental health services.

Multiple memories can be simultaneously reactivated during sleep as effectively as a single memory.

Memory consolidation involves the reactivation of memory traces during sleep. If different memories are reactivated each night, how much do they interfere with one another? We examined whether reactivating multiple memories incurs a cost to sleep-related benefits by contrasting reactivation of multiple memories versus single memories during sleep. First, participants learned the on-screen location of different objects.

BrainIAK: The Brain Imaging Analysis Kit.

Functional magnetic resonance imaging (fMRI) offers a rich source of data for studying the neural basis of cognition. Here, we describe the Brain Imaging Analysis Kit (BrainIAK), an open-source, free Python package that provides computationally optimized solutions to key problems in advanced fMRI analysis. A variety of techniques are presently included in BrainIAK: intersubject correlation (ISC) and intersubject functional connectivity (ISFC), functional alignment via the shared response model (SRM), full correlation matrix analysis (FCMA), a Bayesian version of representational similarity analysis (BRSA), event segmentation using hidden Markov models, topographic factor analysis (TFA), inverted encoding models (IEMs), an fMRI data simulator that uses noise characteristics from real data (fmrisim), and some emerging methods.

Behavioral, Physiological, and Neural Signatures of Surprise during Naturalistic Sports Viewing.

Surprise signals a discrepancy between past and current beliefs. It is theorized to be linked to affective experiences, the creation of particularly resilient memories, and segmentation of the flow of experience into discrete perceived events. However, the ability to precisely measure naturalistic surprise has remained elusive.

Finding the Pattern: On-Line Extraction of Spatial Structure During Virtual Navigation.

While navigating the world, we pick up on patterns of where things tend to appear. According to theories of memory and studies of animal behavior, knowledge of these patterns emerges gradually over days or weeks via consolidation of individual navigation episodes. Here, we discovered that navigation patterns can also be extracted on-line, prior to the opportunity for off-line consolidation, as a result of rapid statistical learning.

Biochemical analyses of Sabin Blue PLBs during cryopreservation by vitrification.

Sabin Blue is an important orchid hybrid that has been grown extensively as cut flower, potted plant and is also popular for its deep purplish blue flowers.  The most efficient long term conservation method of this hybrid is through cryopreservation. Cryopreservation involving the vitrification method consists of explants exposure to highly concentrated cryoprotective solution followed by freezing rapidly in liquid nitrogen.