The diminishing precision of memory for time.

Knowing when an event took place can provide several benefits to episodic memory, such as distinguishing among multiple traces, learning sequences of events, and guiding a search strategy. As a tool for understanding memory, time is particularly appealing given its ever-changing quality, the constant possibility to associate it with encoded events, and the ease with which it can be targeted at retrieval. Whereas studies of episodic retrieval typically employ categorical and probabilistic measures of retrieval success, characterizing a continuous feature such as time warrants measures particularly sensitive to the fidelity, or precision, of retrieved information. Here, we adapt a paradigm for assessing the fine-grained precision of retrieval to understand the nature of judging the time at which a memory was encoded. Subjects studied a series of pictures and then undertook a test in which they placed each picture, as precisely as possible, along a continuous time line representing the study list. Based on mixture-modeling analyses of the test response errors, the primary results were that temporal judgments were less accurate with passing time, and this change was due to diminished precision as opposed to an increased rate of guessing. Moreover, although we observed a negligible influence of guessing, subjects exhibited a clear effect of bias that favored recent responses. Together, in contrast to numerous studies of memory for other continuous features (e.g., color and location), our findings demonstrate a novel pattern of decision factors, suggesting that the retrieval of time might highlight distinct attributes of episodic memory.

Genotype-dependent contribution of CBF transcription factors to long-term acclimation to high light and cool temperature.

When grown under cool temperature, winter annuals upregulate photosynthetic capacity as well as freezing tolerance. Here, the role of three cold-induced C-repeat-binding factor (CBF1-3) transcription factors in photosynthetic upregulation and freezing tolerance was examined in two Arabidopsis thaliana ecotypes originating from Italy (IT) or Sweden (SW), and their corresponding CBF1-3-deficient mutant lines it:cbf123 and sw:cbf123. Photosynthetic, morphological and freezing-tolerance phenotypes, as well as gene expression profiles, were characterized in plants grown from the seedling stage under different combinations of light level and temperature. Under high light and cool (HLC) growth temperature, a greater role of CBF1-3 in IT versus SW was evident from both phenotypic and transcriptomic data, especially with respect to photosynthetic upregulation and freezing tolerance of whole plants. Overall, features of SW were consistent with a different approach to HLC acclimation than seen in IT, and an ability of SW to reach the new homeostasis through the involvement of transcriptional controls other than CBF1-3. These results provide tools and direction for further mechanistic analysis of the transcriptional control of approaches to cold acclimation suitable for either persistence through brief cold spells or for maximisation of productivity in environments with continuous low temperatures.

Aerosol and Droplet Generation from Open Rhinoplasty: Surgical Risk in the Pandemic Era.

Introduction: The coronavirus disease 2019 pandemic has led to concerns over transmission risk from head and neck operations including facial cosmetic surgeries. Objectives: To quantify droplet and aerosol generation from rhinoplasty techniques in a human anatomic specimen model using fluorescein staining and an optical particle sizer. Methods: Noses of human anatomic specimens were infiltrated using 0.1% fluorescein. Droplets and aerosols were measured during rhinoplasty techniques including opening the skin-soft tissue envelope, monopolar electrocautery, endonasal rasping, endonasal osteotomy, and percutaneous osteotomy. Results: No visible droplet contamination was observed for any rhinoplasty techniques investigated. Compared with the negative control of anterior rhinoscopy, total 0.300-10.000 µm aerosols were increased after monopolar electrocautery (p < 0.001) and endonasal rasp (p = 0.003). Opening the skin-soft tissue envelope, endonasal osteotomies, and percutaneous osteotomies did not generate a detectable increase in aerosols (p > 0.15). Discussion and Conclusions: In this investigation, droplets were not observed under ultraviolet light, and aerosol generation was noted only with cautery and endonasal rasping.

Aerosol and droplet generation from orbital repair: Surgical risk in the pandemic era.

INTRODUCTION: The highly contagious COVID-19 has resulted in millions of deaths worldwide. Physicians performing orbital procedures may be at increased risk of occupational exposure to the virus due to exposure to secretions. The goal of this study is to measure the droplet and aerosol production during repair of the inferior orbital rim and trial a smoke-evacuating electrocautery handpiece as a mitigation device. MATERIAL AND METHODS: The inferior rim of 6 cadaveric orbits was approached transconjunctivally using either standard or smoke-evacuator electrocautery and plated using a high-speed drill. Following fluorescein inoculation, droplet generation was measured by counting under ultraviolet-A (UV-A) light against a blue background. Aerosol generation from 0.300-10.000 µm was measured using an optical particle sizer. Droplet and aerosol generation was compared against retraction of the orbital soft tissue as a negative control. RESULTS: No droplets were observed following the orbital approach using electrocautery. Visible droplets were observed after plating with a high-speed drill for 3 of 6 orbits. Total aerosol generation was significantly higher than negative control following the use of standard electrocautery. Use of smoke-evacuator electrocautery was associated with significantly lower aerosol generation in 2 of 3 size groups and in total. There was no significant increase in total aerosols associated with high-speed drilling. DISCUSSION AND CONCLUSIONS: Droplet generation for orbital repair was present only following plating with high-speed drill. Aerosol generation during standard electrocautery was significantly reduced using a smoke-evacuating electrocautery handpiece. Aerosols were not significantly increased by high-speed drilling.

Aerosol and droplet generation from mandible and midface fixation: Surgical risk in the pandemic era.

PURPOSE: The COVID-19 pandemic has led to concerns over transmission risk from healthcare procedures, especially when operating in the head and neck such as during surgical repair of facial fractures. This study aims to quantify aerosol and droplet generation from mandibular and midface open fixation and measure mitigation of airborne particles by a smoke evacuating electrocautery hand piece. MATERIALS AND METHODS: The soft tissue of the bilateral mandible and midface of two fresh frozen cadaveric specimens was infiltrated using a 0.1% fluorescein solution. Surgical fixation via oral vestibular approach was performed on each of these sites. Droplet splatter on the surgeon's chest, facemask, and up to 198.12 cm (6.5 ft) away from each surgical site was measured against a blue background under ultraviolet-A (UV-A) light. Aerosol generation was measured using an optical particle sizer. RESULTS: No visible droplet contamination was observed for any trials of mandible or midface fixation. Total aerosolized particle counts from 0.300-10.000 µm were increased compared to baseline following each use of standard electrocautery (n = 4, p < 0.001) but not with use of a suction evacuating electrocautery hand piece (n = 4, p = 0.103). Total particle counts were also increased during use of the powered drill (n = 8, p < 0.001). CONCLUSIONS: Risk from visible droplets during mandible and midface fixation is low. However, significant increases in aerosolized particles were measured after electrocautery use and during powered drilling. Aerosol dispersion is significantly decreased with the use of a smoke evacuating electrocautery hand piece.

Repetition attenuates the influence of recency on recognition memory: Behavioral and electrophysiological evidence.

Studies of recognition memory often demonstrate a recency effect on behavioral performance, whereby response times (RTs) are faster for stimuli that were previously presented recently as opposed to more remotely in the past. One account of this relationship between performance and presentation lag posits that memories are accessed by serially searching backward in time, such that RT indicates the self-terminating moment of such a process. Here, we investigated the conditions under which this serial search gives way to more efficient means of retrieving memories. Event-related potentials (ERPs) were recorded during a continuous recognition task, in which subjects made binary old/new judgments to stimuli that were each presented up to four times across a range of lags. Stimulus repetition and shorter presentation lag both gave rise to speeded RTs, consistent with previous findings, and we novelly extend these effects to a robust latency measure of the left parietal ERP correlate of retrieval success. Importantly, the relationship between repetition and recency was further elucidated, such that repetition attenuated lag-related differences that were initially present in both the behavioral and neural latency data. These findings are consistent with the idea that an effortful search through recent memory can quickly be abandoned in favor of relying on more efficient "time-independent" cognitive processes or neural signals.

Beta-adrenergic antagonism alters functional connectivity during associative processing in a preliminary study of individuals with and without autism.

Beta-adrenergic antagonism (e.g. propranolol) has been associated with cognitive/behavioral benefits following stress-induced impairments and for some cognitive/behavioral domains in individuals with autism spectrum disorder. In this preliminary investigation, we examined whether the benefits of propranolol are associated with functional properties in the brain. Adolescents/adults (mean age = 22.54 years) with (n = 13) and without autism spectrum disorder (n = 13) attended three sessions in which propranolol, nadolol (beta-adrenergic antagonist that does not cross the blood-brain barrier), or placebo was administered before a semantic fluency task during functional magnetic resonance imaging. Autonomic nervous system measures and functional connectivity between language/associative processing regions and within the fronto-parietal control, dorsal attention, and default mode networks were examined. Propranolol was associated with improved semantic fluency performance, which was correlated with the baseline resting heart rate. Propranolol also altered network efficiency of regions associated with semantic processing and in an exploratory analysis reduced functional differences in the fronto-parietal control network in individuals with autism spectrum disorder. Thus, the cognitive benefits from beta-adrenergic antagonism may be generally associated with improved information processing in the brain in domain-specific networks, but individuals with autism spectrum disorder may also benefit from additional improvements in domain-general networks. The benefits from propranolol may also be able to be predicted from baseline autonomic nervous system measures, which warrants further investigation.

Latent resting-state network dynamics in boys and girls with attention-deficit/hyperactivity disorder.

Neuroimaging studies of subjects with ADHD typically show altered functional connectivity in prefrontal, striatal, and several temporal brain regions. While the majority of studies have focused on connectivity that is averaged over time, we investigated the temporal dynamics of brain network changes in resting-state fMRI. Using the ADHD-200 consortium, we characterized the time course of latent state changes using Hidden Markov Modeling, and compared state changes between boys and girls with ADHD along with typically developing controls. Sex differences were found in latent state switching, with boys dwelling longer in a given state than girls, and concurrently having fewer overall state transitions. These sex differences were found in children with ADHD and in typically developing controls. Children with ADHD were also found to be more variable in terms of state transitions than controls. These findings add to the growing literature on neural sex differences and may be related to the sex difference in focal versus diffuse attention.

Failure to reactivate salient episodic information during indirect and direct tests of memory retrieval.

Several fMRI and EEG studies have demonstrated that successful episodic retrieval is accompanied by the reactivation of cortical regions that were active during encoding. These findings are consistent with influential models of episodic memory that posit that conscious retrieval (recollection) relies on hippocampally-mediated cortical reinstatement. Evidence of reactivation corresponding to episodic information that is beyond conscious awareness at the time of memory retrieval, however, is limited. A recent exception is from an EEG study by Wimber, Maaß, Staudigl, Richardson-Klavehn, and Hanslmayr et al. (2009) in which words were encoded in the context of highly salient visual flicker entrainment and then presented at retrieval in the absence of any flicker. In that study, coherent (phase-locked) neural activity was observed at the corresponding entrained frequencies during retrieval, consistent with the notion that encoding representations were reactivated. Given the important implications of unconscious reactivation to past findings and the modeling literature, the current study set out to provide a direct replication of the previous study. Additionally, an attempt was made to extend such findings to intentional retrieval by acquiring EEG while subjects were explicitly asked to make memory judgments about the flicker frequency from encoding. Throughout a comprehensive set of analyses, the current study consistently failed to demonstrate evidence for unconscious reactivation, and instead provided support that test items were indistinguishable according to their prior encoding context. The findings thus establish an important boundary condition for the involvement of cortical reinstatement in episodic memory.

Beta-adrenergic antagonism modulates functional connectivity in the default mode network of individuals with and without autism spectrum disorder.

The beta-adrenergic antagonist propranolol benefits some social and communication domains affected in autism spectrum disorder (ASD), and these benefits appear to be associated with increased functional connectivity (FC) in the brain during task performance. FC is implicated in ASD, with the majority of studies suggesting long distance hypo-connectivity combined with regionally specific local hyper-connectivity. The objective in the current investigation was to examine the effect of propranolol on FC at rest and determine whether ASD-specific effects exist. Participants with and without ASD attended three sessions in which propranolol, nadolol (a beta-adrenergic antagonist that does not cross the blood-brain barrier), or placebo were administered. Resting-state fMRI data were acquired, and graph theory techniques were utilized to assess additional aspects of FC. Compared to placebo, propranolol administration was associated with decreased FC in the dorsal medial prefrontal cortex subnetwork of the default mode network and increased FC in the medial temporal lobe subnetwork, regardless of diagnosis. These effects were not seen with nadolol suggesting that the alterations in FC following propranolol administration were not exclusively due to peripheral cardiovascular effects. Thus, beta-adrenergic antagonism can up- or down- regulate FC, depending on the network, and alter coordinated functional activation in the brain. These changes in information processing, as demonstrated by FC, may mediate some of the clinical and behavioral effects of beta-adrenergic antagonism previously reported in patients with ASD.

Vibratory stimulus reduces in vitro biofilm formation on tracheoesophageal voice prostheses.

OBJECTIVES/HYPOTHESIS: Demonstrate that biofilm formation will be reduced on tracheoesophageal prostheses when vibratory stimulus is applied, compared to controls receiving no vibratory stimulus, in a dynamic in vitro model of biofilm accumulation simulating the interface across the tracheoesophageal puncture site. STUDY DESIGN: Prospective, randomized, controlled, crossover in university laboratory. METHODS: Ex vivo tracheoesophageal prostheses were obtained from university-affiliated speech language pathologists at Indiana University School of Medicine, Indianapolis. Prostheses demonstrating physical integrity and an absence of gross biofilm accumulation were utilized. Sixteen prostheses were cleansed and sterilized prior to random placement by length in two modified Robbins devices arranged in parallel. Each device was seeded with a polymicrobial oral flora on day 1 and received basal artificial salivary flow continuously with three growth medium meals daily. One device was randomly selected for vibratory stimulus, and 2 minutes of vibration was applied to each prosthesis before and after meals for 5 days. The prostheses were explanted and sonicated, and the biofilm cultured for enumeration. This process was repeated after study arm crossover. RESULTS: Tracheoesophageal prostheses in the dynamic model receiving vibratory stimulus demonstrated reduced gross biofilm accumulation and a significant biofilm colony forming unit per milliliter reduction of 5.56-fold compared to nonvibratory controls (P < 0.001). Significant reductions were observed within length subgroups. CONCLUSION: Application of vibratory stimulus around meal times significantly reduces biofilm accumulation on tracheoesophageal prostheses in a dynamic in vitro model. Further research using this vibratory stimulus method in vivo will be required to determine if reduced biofilm accumulation correlates with longer device lifespan. LEVEL OF EVIDENCE: NA Laryngoscope, 126:2752-2757, 2016.

The Effects of Age on the Neural Correlates of Recollection Success, Recollection-Related Cortical Reinstatement, and Post-Retrieval Monitoring.

Functional magnetic resonance imaging (fMRI) was used to investigate whether age-related differences in episodic memory performance are accompanied by a reduction in the specificity of recollected information. We addressed this question by comparing recollection-related cortical reinstatement in young and older adults. At study, subjects viewed objects and concrete words, making 1 of 2 different semantic judgments depending on the study material. Test items were words that corresponded to studied words or the names of studied objects. Subjects indicated whether each test item was recollected, familiar, or novel. Reinstatement of information differentiating the encoding tasks was quantified both with a univariate analysis of the fMRI signal and with a multivoxel pattern analysis, using a classifier that had been trained to discriminate between the 2 classes of study episode. The results of these analyses converged to suggest that reinstatement did not differ according to age. Thus, there was no evidence that specificity of recollected information was reduced in older individuals. Additionally, there were no age effects in the magnitude of recollection-related modulations in regional activity or in the neural correlates of post-retrieval monitoring. Taken together, the findings suggest that the neural mechanisms engaged during successful episodic retrieval can remain stable with advancing age.

Electrophysiological evidence for strategically orienting retrieval toward the specific age of a memory.

For over a century, memory researchers have extensively studied the differences between retrieving memories that were encoded in the remote past as opposed to recently. Although this work has largely focused on the changes that these memory traces undergo over time, an unexplored issue is whether retrieval attempts and other strategic processes might be differentially oriented in order to effectively access memories of different ages. The current study addressed this issue by instructing participants to retrieve words that were encoded either one week (remote) or about 30 minutes earlier (recent). To maximize the possibility that participants adopted distinct retrieval orientations, separate blocks of the memory test employed exclusion task procedures in which the words from only one encoding period were targeted at a given time, in the face of distractors from the other period. Event-related potentials (ERPs) elicited by correctly-rejected new items were contrasted to minimize confounding effects of retrieval success. The new-item ERPs revealed differences according to the targeted week, such that the ERPs over posterior scalp were more positive-going for the recent compared to remote blocks. Furthermore, using multiple methods, these ERP effects were dissociated from differences in difficulty across the two conditions. The findings provide novel evidence that knowledge about when a memory was initially encoded leads to differences in the adoption of retrieval processing strategies.

Pattern reactivation co-varies with activity in the core recollection network during source memory.

Neuroimaging studies of episodic memory have consistently demonstrated that memory retrieval involves reactivating patterns of neural activity that were present during encoding, and these effects are thought to reflect the qualitative retrieval (recollection) of information that is specific to the content of an episode. By contrast, recollection is also accompanied by other neural correlates that generalize across episodic content and are consequently referred to as the "core recollection network". The neural mechanism by which these specific and core effects interact to give rise to episodic memory retrieval is largely unknown. The current study addressed this issue by testing for correlations (connectivity) between pattern reactivation and activity in the core recollection network. Subjects encoded a series of words with different tasks and then completed a two-step source memory test, whereby they identified the task (source) previously associated with the word and the confidence of that judgment. Multivariate pattern analysis (MVPA) was used in combination with fMRI to first identify encoding-related neural patterns and then test for their reactivation during retrieval. Consistent with prior findings, the magnitude of reactivation increased with source-memory confidence. Moreover, individual-trial measures of reactivation exhibited positive correlations with activity in multiple regions of the core recollection network. Importantly, evidence of functional connectivity between pattern reactivation and a region of left posterior parietal cortex supports the role of this region in tracking the retrieval of episodic information in service of making subjective memory decisions.

Episodic retrieval involves early and sustained effects of reactivating information from encoding.

Several fMRI studies have shown a correspondence between the brain regions activated during encoding and retrieval, consistent with the view that memory retrieval involves hippocampally-mediated reinstatement of cortical activity. With the limited temporal resolution of fMRI, the precise timing of such reactivation is unclear, calling into question the functional significance of these effects. Whereas reactivation influencing retrieval should emerge with neural correlates of retrieval success, that signifying post-retrieval monitoring would trail retrieval. The present study employed EEG to provide a temporal landmark of retrieval success from which we could investigate the sub-trial time course of reactivation. Pattern-classification analyses revealed that early-onsetting reactivation differentiated the outcome of recognition-memory judgments and was associated with individual differences in behavioral accuracy, while reactivation was also evident in a sustained form later in the trial. The EEG findings suggest that, whereas prior fMRI findings could be interpreted as reflecting the contribution of reinstatement to retrieval success, they could also indicate the maintenance of episodic information in service of post-retrieval evaluation.

Neural reinstatement and the amount of information recollected.

Recent functional neuroimaging studies have attempted to understand the cognitive and neural bases of episodic memory retrieval, as well as the extent to which different retrieval judgments reflect qualitative as opposed to continuous changes in neural signals. The present study addressed this issue by investigating the reinstatement of episodic content according to the amount of information available at retrieval. Subjects encoded a series of words in the context of three distinct tasks, while a manipulation of presentation duration (4 or 8s) was also employed. A later recognition memory test was used to segregate trials according to whether or not they were accompanied by the recollection of details from encoding. Functional MRI data acquired during both the encoding and retrieval phases were used in conjunction with multi-voxel pattern-analysis (MVPA) to provide a measure of the degree to which encoding-related patterns of brain activity were later reactivated (reinstated) at the time of retrieval. Critically, the magnitude of reinstatement differed with respect to the encoding manipulation, such that reinstatement was stronger for items associated with the longer presentation duration. Together with duration-related differences in retrieval activity in left posterior parietal cortex, the results provide neural evidence for the reinstatement of different amounts of episodic information, consistent with the idea that recollection is based on a continuous neural signal.

The Synthetic Biology Open Language (SBOL) provides a community standard for communicating designs in synthetic biology.

The re-use of previously validated designs is critical to the evolution of synthetic biology from a research discipline to an engineering practice. Here we describe the Synthetic Biology Open Language (SBOL), a proposed data standard for exchanging designs within the synthetic biology community. SBOL represents synthetic biology designs in a community-driven, formalized format for exchange between software tools, research groups and commercial service providers. The SBOL Developers Group has implemented SBOL as an XML/RDF serialization and provides software libraries and specification documentation to help developers implement SBOL in their own software. We describe early successes, including a demonstration of the utility of SBOL for information exchange between several different software tools and repositories from both academic and industrial partners. As a community-driven standard, SBOL will be updated as synthetic biology evolves to provide specific capabilities for different aspects of the synthetic biology workflow.

Goals, symptoms, signs, and treatments among women with pelvic floor disorders.

OBJECTIVE: This study aimed to identify associations between patient-centered goals and pelvic floor measures and treatment choice. METHODS: A retrospective study of women seen for a pelvic floor disorder by a single surgeon in a specialty clinic from January 2008 to December 2009 was done. Goals were categorized as information-seeking, improving across any of 6 pelvic floor symptom categories, and "other." Pelvic floor symptom burden was determined using validated surveys. Health-related quality of life (HRQoL) and vaginal Pelvic Organ Prolapse Quantification points were assessed. Correlations of goals with symptom burden, HRQoL, and anatomic severity and surgical versus nonoperative care were determined. RESULTS: Ninety patients met inclusion criteria. The mean (SD) age was 56 (14) years, with 67% younger than 65 years; 23.3% of the patients reported a surgery treatment preference; 30.7% had at least 1 Pelvic Organ Prolapse Quantification point greater than or equal to 1 cm. A single goal was reported by 18% of patients with 28%, 37%, 14%, and 3.3% reporting 2, 3, 4, or 5 goals. Goals reflected symptom burden for bowel and bladder complaints, whereas a cosmetic goal seems to reflect both prolapse symptoms and impact as well as measurably altered anatomy. Goals related to sexual function reflected overall mental HRQoL but not symptoms or anatomy. Women with an activity-based goal preferred surgery but the low number of patients who chose surgery did allow statistical significance. CONCLUSIONS: There are not always correlations between a patient's therapeutic goals and subjective and objective assessments of the pelvic floor or treatment choice.

Recollection, familiarity, and content-sensitivity in lateral parietal cortex: a high-resolution fMRI study.

Numerous studies have identified brain regions where activity is consistently correlated with the retrieval (recollection) of qualitative episodic information. This 'core recollection network' can be contrasted with regions where activity differs according to the contents of retrieval. The present study used high-resolution fMRI to investigate whether these putatively-distinct retrieval processes engage common versus dissociable regions. Subjects studied words with two encoding tasks and then performed a memory test in which they distinguished between recollection and different levels of recognition confidence. The fMRI data from study and test revealed several overlapping regions where activity differed according to encoding task, suggesting that content was selectively reinstated during retrieval. The majority of recollection-related regions, though, did not exhibit reinstatement effects, providing support for a core recollection network. Importantly, lateral parietal cortex demonstrated a clear dissociation, whereby recollection effects were localized to angular gyrus and confidence effects were restricted to intraparietal sulcus. Moreover, the latter region exhibited a non-monotonic pattern, consistent with a neural signal reflecting item familiarity rather than a generic form of memory strength. Together, the findings show that episodic retrieval relies on both content-sensitive and core recollective processes, and these can be differentiated from familiarity-based recognition memory.

Dissociation of Recollection-Related Neural Activity in Ventral Lateral Parietal Cortex.

fMRI responses to recognition memory test items in two regions of ventral lateral parietal cortex-the angular gyrus and temporo-parietal junction (TPJ)-are enhanced when recognition is accompanied by recollection. According to the 'episodic buffer' hypothesis, ventral parietal recollection effects reflect processes involved in maintaining or representing recollected information. According to the 'attention to memory' hypothesis, however, the effects reflect attentional re-orienting to the products of recollection. The present experiment addressed the question whether these operations map on to the angular gyrus and TPJ, respectively. Subjects were scanned during a memory test that required a Remember/Know/New and a source memory judgment, allowing recollected items to be segregated by amount of contextual information recollected. Angular gyrus activity tracked amount of recollected information, whereas activity in the TPJ was enhanced for items endorsed as recollected, but was insensitive to amount of information recollected. Thus, the two regions likely support functionally dissociable processes.