Recall initiation instructions influence how space and time interact in memory.

Recent work has examined the interaction between space and time in memory search, but there is still limited understanding of this relationship. Here, we test the hypothesis that individuals can exert control over how time and space interact in response to subtle differences in task instructions. To test this hypothesis, we analyzed two experiments where participants completed two immediate free recall tasks, a verbal task involving words presented at a central location and a spatial task involving squares presented at different locations. Some participants were free to recall the words or locations spontaneously in any order they preferred. In contrast, another group was subtly biased toward temporal information by instructions to begin recall from the last presented item before recalling the remaining items in any order they wished. Replicating recent work, all conditions showed clear evidence that recall was organized along both the temporal and the spatial dimensions. Extending this work, we found that the subtle change in recall instructions increased the reliance on temporal information in the spatial recall task. Correlational analyses suggest that spatial and temporal information do not compete when participants search memory spontaneously. However, they do compete when instructions favor temporal information. These findings highlight that individuals can exert some cognitive control over how associative dimensions interact during memory search and emphasize the importance of incorporating such processes into theoretical models.

Testing locus coeruleus-norepinephrine accounts of working memory, attention control, and fluid intelligence.

The current set of studies examined the relationship among working memory capacity, attention control, fluid intelligence, and pupillary correlates of tonic arousal regulation and phasic responsiveness in a combined sample of more than 1,000 participants in two different age ranges (young adults and adolescents). Each study was designed to test predictions made by two recent theories regarding the role of the locus coeruleus-norepinephrine (LC-NE) system in determining individual differences in cognitive ability. The first theory, proposed by Unsworth and Robison (2017a), posits two important individual differences: the moment-to-moment regulation of tonic arousal, and the phasic responsiveness of the system to goal-relevant stimuli. The second theory, proposed by Tsukahara and Engle (2021a), argues that people with higher cognitive abilities have greater functional connectivity between the LC-NE system and cortical networks at rest. These two theories are not mutually exclusive, but they make different predictions. Overall, we found no evidence consistent with a resting-state theory. However, phasic responsiveness was consistently correlated with working memory capacity, attention control, and fluid intelligence, supporting a prediction made by Unsworth and Robison (2017a). Tonic arousal regulation was not correlated with working memory or fluid intelligence and was inconsistently correlated with attention control, which offers only partial support for Unsworth and Robison's (2017a) second prediction.

MEF2B is a member of the BCL6 gene transcriptional complex and induces its expression in diffuse large B-cell lymphoma of the germinal center B-cell-like type.

Myocyte enhancer-binding factor 2B (MEF2B) has been implicated as a transcriptional regulator for BCL6. However, details about the interaction between MEF2B and BCL6 during expression, as well as the relationship of MEF2B to the expression of other germinal center (GC) markers, have not yet been fully explained. Using germinal center B-cell-like diffuse large B-cell lymphoma (GC-DLBCL) and activated B-cell diffuse large B-cell lymphoma (ABC-DLBCL) cell lines, we analyzed the expression of MEF2B and its associations with BCL6, CD10, and ERK. Furthermore, small interfering RNA (siRNA) was used to study the possible effects of MEF2B knockdown on these proteins and cell growth. Analysis of the BCL6 transcriptional complex was performed using electrophoretic mobility shift assay. The correlation between MEF2B expression and the genetic type of DLBCL was assessed using immunohistochemistry on 111 patient samples, and via in silico analysis of publicly available microarray (Gene Expression Omnibus (GEO)) datasets. Our results indicate that the expression of MEF2B protein is important for the growth of GC-DLBCL cells, as evidenced by MEF2B knockdown inhibition of cell growth and the subsequent suppression of BCL6, CD10, and ERK phosphorylation. Analysis of BCL6 transcription factors in nuclear extracts of MEF2-expressing DLBCL cells showed involvement of MEF2B with AP-2α and BCL6 proteins in the formation of the BCL6 gene transcriptional complex. Indeed, differential expression of MEF2B in the GC-DLBCL is statistically significant compared to the ABC-DLBCL in the GEO datasets, as well as in tissue microarray, as indicated via immunohistochemistry (Visco-Young algorithm). Our findings indicate that MEF2B is an essential component of the BCL6 gene transcriptional complex for the regulation of DLBCL growth via the promotion of BCL6 expression. Beyond its regulatory role in DLBCL growth, MEF2B expression correlated positively with BCL6 and CD10 expression, and was preferentially expressed in the GBC-DLBCL group.

Miniaturized ring-down spectrometer for CubeSat-based planetary science.

A robust, miniaturized cavity ring-down spectrometer has been developed as a laboratory demonstration model for future CubeSat deployments of near- and mid-infrared spectrometers for in situ planetary science. The spectrometer is compact enough to ensure compatibility with standard CubeSat spacecraft buses, with a probed gas volume of less than 2.5 cc to ease mass, volume, and power requirements of sample gas handling subsystems. When operated at 1.39 µm for water vapor isotope measurements, a noise-equivalent absorption coefficient of 3.7×10-9 cm-1 Hz-1/2 is obtained. Oxygen isotope measurements were performed to demonstrate scanning performance. The spectrometer has been designed to use only components with functional equivalents throughout the 1-5 µm range to maintain flexibility across a wide array of planetary science targets. Preliminary results from a 3.27 µm implementation intended for methane measurements are also presented.

Adjacent-resonance etalon cancellation in ring-down spectroscopy.

Adjacent-resonance etalon cancellation provides a means of significantly reducing both systematic and random errors introduced in cavity ring-down spectroscopy by unwanted etalons. By stretching the ring-down cavity symmetrically about its center point and collecting two data sets at cavity lengths separated by λ/2, two fringing components offset in phase by 180 deg are obtained. When these two data sets are averaged, oscillations in effective mirror reflectivities due to fringing are dramatically reduced. The technique is demonstrated in a 12 cm monolithic ring-down spectrometer. Long-term time constant measurements show a decrease in noise-equivalent absorption and an increase in maximum effective averaging time due to a reduction in noise coupled in by etalons; trace water spectra demonstrate how removing the systematic fringing components eases absorption peak identification.

Unmasking the component-general and component-specific aspects of primary and secondary memory in the immediate free recall task.

The immediate free recall (IFR) task has been commonly used to estimate the capacities of the primary memory (PM) and secondary memory (SM) components of working memory (WM). Using this method, the correlation between estimates of the PM and SM components has hovered around zero, suggesting that PM and SM represent fully distinct and dissociable components of WM. However, this conclusion has conflicted with more recent studies that have observed moderately strong, positive correlations between PM and SM when separate attention and retrieval tasks are used to estimate these capacities, suggesting that PM and SM represent at least some related capacities. The present study attempted to resolve this empirical discrepancy by investigating the extent to which the relation between estimates of PM and SM might be suppressed by a third variable that operates during the recall portion of the IFR task. This third variable was termed "strength of recency" (SOR) in the present study as it reflected differences in the extent to which individuals used the same experimentally-induced recency recall initiation strategy. As predicted, the present findings showed that the positive correlation between estimates of PM and SM grew from small to medium when the indirect effect of SOR was controlled across two separate sets of studies. This finding is important because it provides stronger support for the distinction between "component-general" and "component-specific" aspects of PM and SM; furthermore, a proof is presented that demonstrates a limitation of using regression techniques to differentiate general and specific aspects of these components.

Evaluating Amazon's Mechanical Turk for psychological research on the symbolic control of attention.

The use of online crowdsourcing services like Amazon's Mechanical Turk (AMT) as a method of collecting behavioral data online has become increasingly popular in recent years. A growing body of contemporary research has empirically validated the use of AMT as a tool in psychological research by replicating a wide range of well-established effects that have been previously reported in controlled laboratory studies. However, the potential for AMT to be used to conduct spatial cuing experiments has yet to be investigated in depth. Spatial cuing tasks are typically very basic in terms of their stimulus complexity and experimental testing procedures, thus making them ideal for remote testing online that requires minimal task instruction. Studies employing the spatial cuing paradigm are typically aimed at unveiling novel facets of the symbolic control of attention, which occurs whenever observers orient their attention through space in accordance with the meaning of a spatial cue. Ultimately, the present study empirically validated the use of AMT to study the symbolic control of attention by successfully replicating four hallmark effects reported throughout the visual attention literature: the left/right advantage, cue type effect, cued axis effect, and cued endpoint effect. Various recommendations for future endeavors using AMT as a means of remotely collecting behavioral data online are also provided. In sum, the present study provides a crucial first step toward establishing a novel tool for conducting psychological research that can be used to expedite not only our own scientific contributions, but also those of our colleagues.

Tilt-tuned etalon locking for tunable laser stabilization.

Locking to a fringe of a tilt-tuned etalon provides a simple, inexpensive method for stabilizing tunable lasers. Here, we describe the use of such a system to stabilize an external-cavity quantum cascade laser; the locked laser has an Allan deviation of approximately 1 MHz over a one-second integration period, and has a single-scan tuning range of approximately 0.4 cm(-1). The system is robust, with minimal alignment requirements and automated lock acquisition, and can be easily adapted to different wavelength regions or more stringent stability requirements with minor alterations.

Working memory, situation models, and synesthesia.

Research on language comprehension suggests a strong relationship between working memory span measures and language comprehension. However, there is also evidence that this relationship weakens at higher levels of comprehension, such as the situation model level. The current study explored this relationship by comparing 10 grapheme-color synesthetes who have additional color experiences when they read words that begin with different letters and 48 normal controls on a number of tests of complex working memory capacity and processing at the situation model level. On all tests of working memory capacity, the synesthetes outperformed the controls. Importantly, there was no carryover benefit for the synesthetes for processing at the situation model level. This reinforces the idea that although some aspects of language comprehension are related to working memory span scores, this applies less directly to situation model levels. This suggests that theories of working memory must take into account this limitation, and the working memory processes that are involved in situation model construction and processing must be derived.

Attention shifts in the spatial cueing paradigm reflect direct influences of experience and not top-down goals.

The spatial cueing effect (SCE) that is elicited by informative spatial cues serves as an empirical marker of attention shifts in the spatial cueing paradigm, and it has been widely interpreted to reflect a relatively pure form of top-down attention control. Contrary to this interpretation, the present study examined the extent to which the magnitude of the SCE could be due to learned associations between specific cues and shifts of attention to the corresponding location, while attempting to track potential changes in participants' task goals across the experiment. This was accomplished by using a novel two-choice, spatial cueing paradigm in which participants chose between two spatial validity contexts. One spatial validity context always involved a 25%-valid (uninformative) arrow cue - called the "test" context; whereas the alternate context - called the "inducing" context - was varied between groups. In particular, associations between specific cues and shifts of attention to the corresponding cued location were perfectly predictable in the "strong inducing" context (100%-valid arrow cues) and imperfectly predictable in the "weak inducing" context (70%-valid arrow cues). Consistent with the experience-dependent account, the results showed that the magnitude of the SCE observed in the test context increased as an individual's experience with the strong inducing context increased. Furthermore, these context effects were observed using both overlearned (arrow) and arbitrary (number) cues, as well as when eye movements were controlled. Altogether, these findings suggest that the magnitude of the SCE can be influenced directly by experience, and not by the top-down goals of the individual.

Exploration of an adaptive training regimen that can target the secondary memory component of working memory capacity.

The dual-component model contends that working memory (WM) capacity consists of two components. The first is a flexible attention component that involves the active maintenance of a limited amount of information in primary memory (PM), and the second is a controlled retrieval component that involves a cue-dependent search of secondary memory (SM) for information that has been lost from PM. Recent evidence has suggested that the adaptive WM training regimen known as "Cogmed-RM" is not optimally designed, because it only targets PM abilities, not SM abilities. The present study was conducted to investigate whether Cogmed-RM could be modified to target SM abilities by decreasing the recall accuracy threshold that defines individual ability during training. The main findings suggested that the SM component of WM capacity could be targeted by lowering the recall accuracy threshold. The present findings are important because they suggest that adaptive training regimens can be designed that selectively target specific components of WM capacity, and they raise the possibility that the potency of existing training regimens can be increased.

Top-down attention control does not imply voluntary attention control for all individuals.

Top-down information is known to play an important role in the control of visual attention. Often, evidence for top-down attention control is also interpreted as evidence for voluntary attention control. However, this latter theoretical interpretation is not warranted because volition is typically defined in terms of a conscious feeling that prior intentions led to a subsequent action, but this aspect of performance has not been assessed in previous studies. Accordingly, the present study used the construct of "agency" within the context of the spatial cuing paradigm to examine the relation between top-down and voluntary attention control. The results of two experiments consistently showed using growth-curve modeling that standard manipulations of top-down information in the spatial cuing paradigm do not have the same effect on all participants. In particular, the present findings showed that a slight majority of individuals (~60%) exhibited the expected pattern in which they reported feeling more agency when they performed visual search with the aid of an informative (arrow or onset) cue than when they performed this task with an uninformative cue or without any cue at all. However, more importantly, these findings also showed that a substantial number of individuals (~40%) exhibited the opposite pattern in which they reported feeling more agency when they performed visual search with an uninformative cue or without any cue at all. We conclude that the relation between top-down and voluntary attention control is not straightforward and must be studied using methods that are sensitive to individual differences. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Partial recall: Implications for the discrete slot limit of working memory capacity.

The nature of working memory capacity (WMC) has been a highly contested topic among cognitive scientists. Some advocate for the discrete nature of this construct, fixed to a set number of independent slots, each capable of storing a single chunk of bound information. Others advocate for a continuous limit, guided by a pool of immediately available resources spent across the to-be-remembered items. To understand the nature of WMC, it was first essential to separate capacity from other factors, such as performance consistency, which may impact overall WM performance. Recent work by Schor et al., (2020, Psychonomic Bulletin & Review, 27[5], 1006-1013) has provided a method for separating these constructs within a single visual array task. The present study used this statistical model to extract partial information, defined as accurate recall of a correct color, but not location, at a rate greater than expected through guessing. The successful memory of this information would demonstrate that capacity does not rely on the existence of empty slots, which discrete slot model advocates argue, are necessary for successful storage and recall of items. The present study found that participants were able to successfully recall partial information at a rate significantly greater than chance, but not beyond the individual working memory capacity limit. These findings help provide additional support for the discrete resource slot model, while simultaneously casting doubt on its strong object slot model alternative.

Rectal Tonsil in a Patient With Positive Syphilis Serology.

Rectal tonsils are an abnormal reactive proliferation of lymphoid tissue in the rectum. Typical lymphoid tissue of the colon and rectum can proliferate with an increased number of germinal centers in response to exposure to an antigen in the GI tract. This response, in rare cases, escalates to the proliferation of a lymphoid mass known as a rectal tonsil. Here, we present a case of a 46-year-old woman with iron deficiency anemia who underwent colonoscopy with incidental finding of a rectal tonsil. This report discusses initial clinical workup, colonoscopy findings, pathological analysis, subsequent testing, and surgical removal of the identified mass and this rare finding.

Pupillary correlates of individual differences in long-term memory.

The present study is the first to examine individual differences in long-term memory, arousal dysregulation, and intensity of attention within the same experiment. Participants (N = 106) completed 28 lists of an immediate free-recall task while their pupil diameter was recorded via an eye-tracker during the encoding period. Two main pupillary measures were extracted: intraindividual variability in pre-list pupil diameter and evoked pupillary responses during item encoding. Variability in pre-list pupil diameter served as a measure of arousal dysregulation, and evoked pupillary responses served as a measure of intensity of attention. Based on prior work, we hypothesized that there would be a positive association between intensity of attention and recall ability, and that there would be a negative association between arousal dysregulation and recall ability. Collectively these two measures accounted for 19% of interindividual variance in recall, with 5% attributable uniquely to intensity of attention and 12% attributable uniquely to arousal regulation. The findings demonstrate that there are sources of individual differences in long-term memory that can be revealed via pupillometry, notably the amount of effort deployed during item encoding and the degree to which people exhibit dysregulated arousal. Both findings are consistent with recent theorizing regarding the role of the locus coeruleus (LC)-norepinephrine (NE) system's role in goal-directed cognition. Specifically, the LC governs both moment-to-moment arousal and NE release to cortical regions subserving cognitive processing. Among people for whom this system operates most optimally, long-term memory retention is superior.

Space and time in the similarity structure of memory.

Space and time are both essential aspects of human episodic memory. Yet, behavioral studies into the dynamics of recall have focused more on time than space. For instance, it is now well known that temporally contiguous events are more likely to be subsequently recalled than temporally remote events, as measured by the lag-conditional response probability (lag-CRP), which represents the probability of recalling item i + lag after recalling item i. The present study administered both verbal and spatial delayed free recall (DFR) tasks to a sample of 168 participants in order to measure lag-CRPs along both spatial and temporal associative dimensions. Whereas only the temporal lag-CRP could be measured in the verbal DFR task, both temporal and spatial lag-CRPs could be measured in the spatial DFR task. As expected, the results obtained in the verbal DFR task indicated the typical temporal contiguity effect. More importantly, the results obtained in the spatial DFR task indicated significant contiguity effects along both associative dimensions, and the spatial contiguity effect was found to be significantly larger than the temporal contiguity effect. In addition, the relatively small temporal contiguity effect observed in the spatial DFR task was also found to be significantly smaller than the temporal contiguity effect observed in the verbal DFR task. Altogether, the present findings provided novel evidence that spatial and temporal proximity can both cue sequential dependencies between successive recalls. As such, retrieved context models of episodic memory should be expanded to include spatial context as well as temporal context.

The misrepresentation of spatial uncertainty in visual search: Single- versus joint-distribution probability cues.

The present study used information theory to quantify the extent to which different spatial cues conveyed the entropy associated with the identity and location of a visual search target. Single-distribution cues reflected the probability that the target would appear at one fixed location whereas joint-distribution cues reflected the probability that the target would appear at the location where another cue (arrow) pointed. The present study used a novel demand-selection paradigm to examine the extent to which individuals explicitly preferred one type of probability cue over the other. Although both cues conveyed equal entropy, the main results suggested representation of greater target entropy for joint- than for single-distribution cues based on a comparison between predicted and observed probability cue choices across four experiments. The present findings emphasize the importance of understanding how individuals represent basic information-theoretic quantities that underlie more complex decision-theoretic processes such as Bayesian and active inference.

A model comparison approach reveals individual variation in the scope and control of attention.

The maintenance capacity of working memory is known to be severely limited in scope. However, the reason this capacity varies across individuals remains unknown because it has proven difficult to estimate the maximum capacity of an individual's "scope of attention" (SoA) separate from their ability to achieve this maximum capacity due to temporary lapses in "attention control" (AC). The present study accomplished this separation by using a maximum likelihood framework to extract latent constructs representing SoA and AC from a whole-report version of the visual-array task. The results of two experiments (N = 145 and N = 189) showed that model fit was significantly greater when the model allowed both AC and SoA to vary across individuals relative to a model in which only AC was allowed to vary (and SoA was fixed). More importantly, the individual estimates of SoA and AC derived from this variable model suggested that (1) the observed range of SoA was found to be small across individuals, with 91% able to maintain a maximum of 3 or 4 items; (2) the consistency with which AC could be deployed was only weakly correlated with the magnitude of SoA; and (3) AC and SoA were both found to be significant predictors of fluid intelligence. Altogether, the present study clarified the nature of maintenance capacity and suggested that SoA and AC both need to be included in a mechanistic account of complex cognition.