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Despite the massive capacity of visual long-term memory, individuals do not successfully encode all visual information they wish to remember. This variability in encoding success has been traditionally ascribed to fluctuations in individuals’ cognitive states (e.g., sustained attention) and differences in memory encoding processes (e.g., depth of encoding). However, recent work has shown that a considerable amount of variability in encoding success stems from intrinsic stimulus properties that determine the ease of encoding across individuals. While researchers have identified several perceptual and semantic properties that contribute to stimulus memorability, much remains unknown, including whether individuals are aware of the memorability of stimuli they encounter. In the present study, we investigated whether individuals have conscious access to the memorability of real-world stimuli while forming self-referential judgments of learning (JOL) during explicit memory encoding (Experiments 1A–B) and when asked about the perceived memorability of a stimulus in the absence of attempted encoding (Experiments 2A–B). We found that JOLs and perceived memorability estimates (PME) were consistent across individuals and predictive of memorability, confirming that individuals can access memorability with or without stimulus encoding. At the same time, access to memorability was not comprehensive. We found that individuals unexpectedly remembered and forgot consistent sets of stimuli as well. When we compared access to memorability between JOLs and PMEs, we found that individuals had more access during JOLs. Thus, our findings demonstrate that individuals have partial access to stimulus memorability and that explicit encoding increases the amount of access that is available.

Given that the encoding of information into visual long-term memory relies on multiple spatially distinct areas in the human brain, encoding into visual memory is a cognitive process likely to rely on networks formed via large-scale coupled neuronal oscillations. Previous research suggests that decreases in occipital alpha power and increases in mid-frontal theta power individually contribute to the encoding of retrievable representations in visual long-term memory. The present study asks whether these oscillations form a coupled network that operates during long-term memory encoding. Here we show that neither amplitude-amplitude coupling nor phase-amplitude coupling between frontal theta and posterior alpha are correlated with observers’ subsequent memory when storing pictures in visual long-term memory. Correlations between alpha and theta power were stronger during eyes-open, resting-state periods when no task was performed than immediately following the presentation of a to-be-remembered picture. Finally, we also found that the strength of theta-alpha coupling was not modified by temporal lobe anodal transcranial direct current stimulation, despite observers showing enhanced memory for pictures behaviorally. Collectively, these findings indicate that posterior alpha and frontal theta activity are not simply component parts of a larger scale coupled network underlying visual memory.

Some stimuli are more memorable than others. Humans have demonstrated partial access to the properties that make a given stimulus more or less memorable. Recently, a deep neural network named ResMem was shown to successfully decode the memorability of visual stimuli as well. However, it remains unknown whether ResMem’s predictions of memorability reflect the influence of stimulus-intrinsic properties or other stimulus-extrinsic factors that are known to induce inter-individual consistency in memory performance (e.g., inter-stimulus similarity). Additionally, it is not clear whether ResMem and humans share access to overlapping properties of memorability. Here, in three experiments, we show that ResMem predicts stimulus-intrinsic memorability independent of stimulus-extrinsic factors, and that it captures aspects of memorability that are inaccessible to human observers. Taken together, our results confirm the multifaceted nature of memorability and establish a method for isolating its unconscious aspects.

Some visual stimuli are consistently better remembered than others across individuals, due to variations in memorability, or stimulus-intrinsic properties that determine ease of access into visual long-term memory (VLTM). However, it remains unclear what cognitive processes give rise to this mnemonic benefit. One possibility is that this benefit is imbued within the capacity-limited bottleneck of VLTM encoding, namely visual working memory (VWM). More precisely, memorable stimuli may be preferentially encoded into VLTM because fewer cognitive resources are required to represent them efficiently in VWM (efficiency hypothesis). Alternatively, memorable stimuli may be more competitive in obtaining cognitive resources than forgettable stimuli, leading to more successful maintenance in VWM (competitiveness hypothesis). Additionally, the memorability benefit might emerge post-VWM, specifically, if memorable stimuli are less prone to be forgotten (i.e., are “stickier”) than forgettable stimuli after they pass through the encoding bottleneck (stickiness hypothesis). In this study, we conducted two experiments to examine how memorability benefits emerged for VLTM of random human faces (Experiment 1A) and real-world objects (Experiment 1B). Here we found that although memorable stimuli enjoy more efficient and competitive VWM maintenance, only the maintenance efficiency produced reliable benefits in VLTM performance. Additionally, memorable stimuli were also “stickier” after they passed through the encoding bottleneck imposed by VWM. Thus, our results demonstrate that the memorability benefit emerges as a result of interactions between multiple cognitive processes.

Previous research from our lab has shown that recognizing an object stored in visual long-term memory leads to the forgetting of related objects. Here we ask whether context, an integral aspect to modern models of memory, plays a role in induced forgetting. We manipulated the activated context at test, both externally (e.g., changes in testing room) and internally (e.g., 1 hr and 24 hr later). We found that only interfering with the ability to internally reinstate context after 24 hr eliminated induced forgetting. Thus, we demonstrate that mental context reinstatement plays a role in induced forgetting and specify that models of memory should incorporate internal context reinstatement as an underlying factor of forgetting. We also propose a process model of induced forgetting, discuss limitations of laboratory-based memory tasks, and offer a new term, induced suppression, to collectively describe this robust phenomenon. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Most daily tasks require frequent information exchange between working memory (WM) and long-term memory (LTM). However, the factors that modulate the reactivation of LTMs in WM remain to be explored. Here, we tested the effects of anticipated perceptual interference on reactivation using contralateral delay activity (CDA) in the EEG. On each trial, participants saw a previously studied object that was tested after a brief retention interval. In half of the blocks, the retention contained perceptual distractors. Half of the participants had larger CDA on interference blocks (WM preparers) and others on no interference blocks (LTM preparers). WM preparers showed smaller interference costs in accuracy suggesting that preparing against interference via reactivating LTMs in WM is a more effective strategy than relying on passive LTMs. Moreover, in interference blocks, contralateral alpha suppression, an index of spatial attention, disappeared during retention in anticipation of interference, mostly in WM preparers. These results indicate that individuals stopped attending to reactivated memories when anticipating interference, presumably to prevent the involuntary encoding of perceptual distractors that appear at attended locations. Together, these results highlight individual differences in preparing for anticipated interference in recruiting WM to store LTMs, and their effects on proneness to interference.

Comparing a visual memory with new visual stimuli can bias memory content, especially when the new stimuli are perceived as similar. Perceptual comparisons of this kind may play a mechanistic role in memory updating and can explain how memories can become erroneous in daily life. To test this possibility, we investigated whether comparisons can produce other types of memory distortion beyond memory bias that are commonly implicated in erroneous memories (e.g., memory misattribution). We hypothesized that the type of memory distortion induced during a comparison depends on the perceived overlap between the memory and incoming stimulus— when the input is perceived as similar, it biases memory content; when perceived as the same, it replaces memory content. Participants completed a delayed-estimation task in which they compared their memories of color (Exp.1) and shape stimuli (Exp.2) to probe stimuli before reporting memory content. We found systematic errors in participants’ memory reports following perceived similarity and sameness that were towards the probes and larger following perceived sameness. Simulations confirmed that these errors were not explained by noisy encoding processes that occurred before comparisons. Instead, computational modeling suggested that these errors were likely explained by probabilistic replacement of the memory by the probe following perceived sameness and integration between the memory and the probe following perceived similarity. Together, these findings suggest that perceptual comparisons can prompt distinct forms of memory updating that have been described previously and may explain how memories become erroneous during their use in everyday behavior.

It is well-established that stimulus-specific information in visual working memory (VWM) can be systematically biased by new perceptual inputs. These memory biases are commonly attributed to interference that arises when perceptual inputs are physically similar to VWM contents. However, recent work has suggested that explicitly comparing the similarity between VWM contents and new perceptual inputs modulates the size of memory biases above and beyond stimulus-driven effects. Here, we sought to directly investigate this modulation hypothesis by comparing the size of memory biases following explicit comparisons to those induced when new perceptual inputs are ignored (Experiment 1) or maintained in VWM alongside target information (Experiment 2). We found that VWM reports showed larger attraction biases following explicit perceptual comparisons than when new perceptual inputs were ignored or maintained in VWM. An analysis of participants’ perceptual comparisons revealed that memory biases were amplified after perceptual inputs were endorsed as similar—but not dissimilar—to one’s VWM representation. These patterns were found to persist even after accounting for variability in the physical similarity between the target and perceptual stimuli across trials, as well as the baseline memory precision between the distinct task demands. Together, these findings illustrate the causal role of perceptual comparisons in modulating naturally-occurring memory biases.

Aims In patients with heart failure, over‐activation of the cardiac sympathetic nerve (CSN) function is associated with severity of heart failure and worse outcome. The effects of MitraClip therapy on the CSN activity in patients with mitral regurgitation (MR) remained unknown. In this study, we evaluated the impact of the MitraClip therapy on CSN activity assessed by 123I‐metaiodobezylguanidine (MIBG) scintigraphy. Methods and results We enrolled consecutive patients with moderate‐to‐severe (3+) or severe (4+) MR who were scheduled to undergo MitraClip procedure in this prospective observational study. MIBG scintigraphy was performed at baseline and 6 months after the MitraClip procedure to evaluate the heart–mediastinum ratio and washout rate (WR). Changes in these MIBG parameters were analysed. Of the 13 consecutive patients, 10 were successfully treated with MitraClip procedure and completed follow‐up assessment. With regard to the MIBG parameters, changes in the early and delayed heart–mediastinum ratio from baseline to 6 months were not significant (2.16 ± 0.42 to 2.06 ± 0.34, P = 0.38 and 1.87 ± 0.39 to 1.83 ± 0.39, P = 0.43, respectively), whereas WR was significantly decreased (38.6 ± 3.9% to 32.6 ± 3.94%, P = 0.002). Conclusions The CSN activity of the WR on MIBG imaging was improved 6 months after MitraClip therapy in patients with 3+ or 4+ MR.

Despite its unlimited capacity, not all visual information we encounter is encoded into visual long-term memory. Traditionally, variability in encoding success has been ascribed to variability in the types and efficacy of an individual’s cognitive processes during encoding. Accordingly, past studies have identified several neural correlates of variability in encoding success, namely, frontal positivity, occipital alpha power, and frontal theta amplitude, by contrasting the electrophysiological signals recorded during successful and failed encoding processes (i.e., subsequent memory). However, recent research demonstrated individuals remember and forget consistent sets of stimuli, thereby elucidating stimulus-intrinsic factors (i.e., memorability) that determine the ease of memory encoding independent of individual-specific variability in encoding processes. The discovery of memorability raises the possibility that canonical EEG correlates of subsequent memory may reflect variability in stimulus-intrinsic factors rather than individual-specific encoding processes. To test this, we recorded the EEG correlates of subsequent memory while participants encoded 600 images of real-world objects and assessed the unique contribution of individual-specific and stimulus-intrinsic factors on each EEG correlate. Here, we found that frontal theta amplitude and occipital alpha amplitude were only influenced by individual-specific encoding success, whereas frontal positivity was influenced by stimulus-intrinsic and individual-specific encoding success. Overall, our results offer novel interpretations of canonical EEG correlates of subsequent memory by demonstrating a dissociable impact of stimulus-intrinsic and individual-specific factors of memory encoding success.

Visual long-term memory allows us to store a virtually infinite amount of visual information (Brady, Konkle, Alvarez, & Oliva, 2008; Standing, 1973). Despite its massive storage capacity, our ability to encode visual long-term memory fluctuates from moment-to-moment, and for that reason, not every piece of visual information that we wish to encode gets stored into our visual long-term memory. At the same time, we occasionally encounter visual information that we do not wish to remember. To what extent can we control our memory encoding ability at will? Here, we showed that although there are multiple mechanisms to directly up-regulate memory encoding, it is more difficult, if not impossible, to down-regulate memory encoding directly. However, we are capable of down-regulating memory encoding indirectly by biasing attentional allocation away from the encoding of an unwanted stimulus and toward the encoding of a simultaneously encoded item. However, this strategy is effective only if it is exerted prior to perceptual encoding of the unwanted stimulus. Thus, our findings not only support the existence of the biased competition mechanism of voluntary control of memory encoding but also reveals its critical period in indirectly down-regulating memory encoding of unwanted information. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Recognition-induced forgetting, whereby the recognition of targeted memories induces the forgetting of related memories, results from the recognition of old objects and rejection of new objects. Here we asked whether both these tasks are necessary to induce forgetting. Our unique design allowed us to isolate the recognition of old objects from the rejection of new objects by presenting subjects with only new objects, only old objects, and a mixture of both in separate conditions of an old-new recognition task. In all three conditions, we successfully induced forgetting. The magnitude of forgetting was statistically indistinguishable across all three conditions, showing that recognition of old objects and rejection of new objects are each building blocks of forgetting. These findings pinpoint both recognition and rejection as mechanisms underlying recognition-induced forgetting and demonstrate the ubiquity of this forgetting effect.

Background Thrombosis of the internal jugular vein occasionally occurs in association with long-term placement of a central venous catheter; however, such complications rarely involve calcification within the blood vessels. We report a case of calcification and abscess formation around a central venous catheter tip. Case presentation Our patient was an 84-year-old Asian woman who developed a fever that had started approximately 5 months after the placement of a central venous catheter. At the time of presentation, blood tests showed a marked inflammatory response, and chest computed tomography showed a high absorption area and air density around the catheter tip. Therefore, the patient was diagnosed with abnormal intravascular calcification and a deep neck abscess associated with long-term central venous catheter placement. The initial plan was to administer antibiotics and remove the central venous catheter. However, central venous catheter removal was deemed difficult due to the calcification and therefore required an incision. Because of the patient’s advanced age and dementia, her family requested antibiotic treatment only. Following antibiotic treatment, the patient’s inflammatory response normalized, and her fever resolved. The treatment was discontinued, and the patient’s condition gradually stabilized. Conclusions Catheter-related complications of central venous catheter placement include vascular occlusion, extravasation of the infusion, and infection. However, abnormal calcification in the blood vessels is extremely rare, and there has been only one case report of a neonate with central venous catheter-related vascular calcification in Japan. The etiology of intravascular calcification is considered to be related to the infusion content and the infusion rate of high caloric infusions and blood products. The incidence of complications associated with long-term central venous catheter placement is expected to increase with the increasing aging of the population and advances in chemotherapy. The report of the clinical course of this rare case adds to the body of knowledge in this area.