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We constructed physical maps of rice chromosomes 1, 2, and 6–9 with P1-derived artificial chromosome (PAC) and bacterial artificial chromosome (BAC) clones. These maps, with only 20 gaps, cover more than 97% of the predicted length of the six chromosomes. We submitted a total of 193 Mbp of non-overlapping sequences to public databases. We analyzed the DNA sequences of 1316 genetic markers and six centromere-specific repeats to facilitate characterization of chromosomal recombination frequency and of the genomic composition and structure of the centromeric regions. We found marked changes in the relative recombination rate along the length of each chromosome. Chromosomal recombination at the centromere core and surrounding regions on the six chromosomes was completely suppressed. These regions have a total physical length of about 23 Mbp, corresponding to 11.4% of the entire size of the six chromosomes. Chromosome 6 has the longest quiescent region, with about 5.6 Mbp, followed by chromosome 8, with quiescent region about half this size. Repetitive sequences accounted for at least 40% of the total genomic sequence on the partly sequenced centromeric region of chromosome 1. Rice CentO satellite DNA is arrayed in clusters and is closely associated with the presence of Centromeric Retrotransposon of Rice ( CRR)- and RIce RetroElement 7 ( RIRE7)-like retroelement sequences. We also detected relatively small coldspot regions outside the centromeric region; their repetitive content and gene density were similar to those of regions with normal recombination rates. Sequence analysis of these regions suggests that either the amount or the organization patterns of repetitive sequences may play a role in the inactivation of recombination. [ABSTRACT FROM AUTHOR]

Epitaxial insulator (CaF2) layers have been grown on epitaxial metal (CoSi2 and NiSi2) layers on Si(111) by molecular beam epitaxy. The surface morphology and bulk crystallinity are much better for growth on NiSi2, with scanning electron microscopy revealing only small triangular hillocks, and channeling minimum yields as low as 3% measured in the CaF2 using 2.5 MeV 4He+ ions. CaF2 layers grown at 650 °C on CoSi2 consist of a mixture of regions either aligned or rotated 180° with respect to the CoSi2 lattice, while CaF2 layers grown at 550 °C on NiSi2 are of a single orientation, regardless of the orientation of the NiSi2 with respect to the Si substrate. [ABSTRACT FROM AUTHOR]

The capacity to pay attention is important for the cognitive ability, for example, evaluating an object for its qualities. Attention can selectively prioritize the neural processes that are relevant to a given task. Neuroimaging investigations on human attention are primarily focused on vision to the exclusion of other sensory systems, particularly olfaction. Neural underpinnings of human olfactory attention are still not clearly understood. Here, we combined electroencephalographic measurements of olfactory event related potential with electrical neuroimaging to investigate how the neural responses after inhaling the same odor differ between conditions with varying levels of attention, and, in which brain areas. We examined the neural responses when participants attended to a rose-like odor of phenylethyl alcohol for evaluating its pleasantness versus its passive inhalation. Our results gathered significant evidence for attentional modulation of the olfactory neural response. The most prominent effect was found for the late positive component, P3, of olfactory event related potential within a second from the odor onset. The source reconstruction of this data revealed activations in a distributed network of brain regions predominantly in inferior frontal cortex, insula, and  inferior temporal gyrus. These results suggest that the neuronal modulations from attention to olfactory pleasantness may be subserved by this network. [ABSTRACT FROM AUTHOR]

Olfactory perception depends not only on olfactory inputs but also on semantic context. Although multi‐voxel activity patterns of the piriform cortex, a part of the primary olfactory cortex, have been shown to represent odor perception, it remains unclear whether semantic contexts modulate odor representation in this region. Here, we investigated whether multi‐voxel activity patterns in the piriform cortex change when semantic context modulates odor perception and, if so, whether the modulated areas communicate with brain regions involved in semantic and memory processing beyond the piriform cortex. We also explored regional differences within the piriform cortex, which are influenced by olfactory input and semantic context. We used 2 × 2 combinations of word labels and odorants that were perceived as congruent and measured piriform activity with a 1‐mm isotropic resolution using 7T MRI. We found that identical odorants labeled with different words were perceived differently. This labeling effect was observed in multi‐voxel activity patterns in the piriform cortex, as the searchlight decoding analysis distinguished identical odors with different labels for half of the examined stimulus pairs. Significant functional connectivity was observed between parts of the piriform cortex that were modulated by labels and regions associated with semantic and memory processing. While the piriform multi‐voxel patterns evoked by different olfactory inputs were also distinguishable, the decoding accuracy was significant for only one stimulus pair, preventing definitive conclusions regarding the locational differences between areas influenced by word labels and olfactory inputs. These results suggest that multi‐voxel patterns of piriform activity can be modulated by semantic context, possibly due to communication between the piriform cortex and the semantic and memory regions. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Attention Deficit Hyperactivity Disorder (ADHD), a common developmental syndrome with inattention, hyperactivity, and impulsivity, is typically treated with the psychostimulant drug, methylphenidate (MPH). We explored the feasibility of using functional near-infrared spectroscopy (fNIRS) to search for a clinically implementable biological marker for the acute MPH effect on ADHD children. Methods: Following an MPH washout period, twelve ADHD children performed a go/no-go task before and 1.5h after MPH intake. fNIRS was used to monitor the lateral prefrontal cortical hemodynamics of ADHD children performing a go/no-go task. Results: There was no significant activation in the lateral prefrontal cortices examined before MPH intake. However, after MPH intake, significant MPH-elicited activation (oxygenated hemoglobin signal increase) was detected in the right lateral prefrontal cortex (LPFC) implicated with response inhibition functions. There was a large significant correlation between increases in task performance and activation in the right LPFC. Conclusions: The improved cognitive performance was associated with activation in the right LPFC, which might serve as a biological marker to monitor the effect of MPH in ADHD children. Significance: MPH-effect assessment in ADHD children using fNIRS can be performed within a 3h stay at a hospital during a single visit, and thus may be integrated into clinical practice. [Copyright &y& Elsevier]

Abstract: The effect of package images on incidental flavor memory for fruit juice was investigated. Ninety-two participants were allocated to three experimental conditions: (1) apple-label, (2) peach-label, and (3) control-label. In each condition, participants tasted a target flavor stimulus, a 1:1 mixture of 100% pure apple juice and 100% pure peach juice with pictures attached to the cups. Ten minutes later, participants were confronted with samples consisting of varying ratios of 100% peach to 100% apple juice, and were asked to rate their similarity to the target stimuli. Participants were also asked to rate how congruent the juice flavor and the image were at the initial tasting. Apple images modulated memories of the flavors of target stimuli: they shifted toward that of apples. This modulation occurred in participants who perceived the label and flavor as congruent. Peach images did not modulate memories, possibly because the subjects had significantly less experience of drinking peach juice than apple juice. These results reveal that flavor memory can be biased toward that of the image labels during initial tasting. However, memory bias depends on the perceived congruency between labels and flavors, and tasters’ prior experiences. [Copyright &y& Elsevier]

How the human brain translates olfactory inputs into diverse perceptions, from pleasurable floral smells to sickening smells of decay, is one of the fundamental questions in olfaction. To examine how different aspects of olfactory perception emerge in space and time in the human brain, we performed time-resolved multivariate pattern analysis of scalp-recorded electroencephalogram responses to 10 perceptually diverse odors and associated the resulting decoding accuracies with perception and source activities. Mean decoding accuracies of odors exceeded the chance level 100 ms after odor onset and reached maxima at 350 ms. The result suggests that the neural representations of individual odors were maximally separated at 350 ms. Perceptual representations emerged following the decoding peak: unipolar unpleasantness (neutral to unpleasant) from 300 ms, and pleasantness (neutral to pleasant) and perceptual quality (applicability to verbal descriptors such as “fruity” or “flowery”) from 500 ms after odor onset, with all these perceptual representations reaching their maxima after 600 ms. A source estimation showed that the areas representing the odor information, estimated based on the decoding accuracies, were localized in and around the primary and secondary olfactory areas at 100 to 350 ms after odor onset. Odor representations then expanded into larger areas associated with emotional, semantic, and memory processing, with the activities of these later areas being significantly associated with perception. These results suggest that initial odor information coded in the olfactory areas (<350 ms) evolves into their perceptual realizations (300 to >600 ms) through computations in widely distributed cortical regions, with different perceptual aspects having different spatiotemporal dynamics.

Background: Key to curtailing the COVID-19 pandemic are wide-scale screening strategies. An ideal screen is one that would not rely on transporting, distributing, and collecting physical specimens. Given the olfactory impairment associated with COVID-19, we developed a perceptual measure of olfaction that relies on smelling household odorants and rating them online., Methods: Each participant was instructed to select 5 household items, and rate their perceived odor pleasantness and intensity using an online visual analogue scale. We used this data to assign an olfactory perceptual fingerprint, a value that reflects the perceived difference between odorants. We tested the performance of this real-time tool in a total of 13,484 participants (462 COVID-19 positive) from 134 countries who provided 178,820 perceptual ratings of 60 different household odorants., Results: We observe that olfactory ratings are indicative of COVID-19 status in a country, significantly correlating with national infection rates over time. More importantly, we observe indicative power at the individual level (79% sensitivity and 87% specificity). Critically, this olfactory screen remains effective in participants with COVID-19 but without symptoms, and in participants with symptoms but without COVID-19., Conclusions: The current odorant-based olfactory screen adds a component to online symptom-checkers, to potentially provide an added first line of defense that can help fight disease progression at the population level. The data derived from this tool may allow better understanding of the link between COVID-19 and olfaction., Competing Interests: Competing interestsThe authors declare no competing interests., (© The Author(s) 2022.)

Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments, such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation, and initial results of a multilingual, international questionnaire to assess self-reported quantity and quality of perception in 3 distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, and 8 others, aged 19-79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste, and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change ±100) revealed a mean reduction of smell (-79.7 ± 28.7, mean ± standard deviation), taste (-69.0 ± 32.6), and chemesthetic (-37.3 ± 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell but also affects taste and chemesthesis. The multimodal impact of COVID-19 and the lack of perceived nasal obstruction suggest that severe acute respiratory syndrome coronavirus strain 2 (SARS-CoV-2) infection may disrupt sensory-neural mechanisms., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The elucidation of odour awareness in children with autism spectrum disorders (ASD) is important. We compared the odour awareness of young children with ASD with those of typical development (TD) children using the Children's Olfactory Behavior in Everyday Life (COBEL) questionnaire, which is a self-report measure that mainly assesses odour awareness. Forty-five young boys (aged 5-6 years), including 20 children with ASD and 25 TD children, participated in this study. The total COBEL score of the young children with ASD was lower than that of the TD children (p < 0.01). Moreover, the total COBEL score was significantly correlated with the total VABS II score (p < 0.05). Our results improve understanding of the odour awareness in children with ASD.

Olfactory traits in individuals with autism spectrum disorder (ASD) are considered the strongest predictors of social impairment. Compared to other sensory abnormalities, olfactory abnormalities in individuals with ASD are poorly understood. In this chapter, we provide an overview of the current assessment in individuals with ASD. Several confounding factors have to be considered when conducting research on olfaction in individuals with ASD. Qualitative measures of olfaction contain only limited information about the olfactory stimuli. In addition, little systematic information is available about individual's actual uses of olfaction in daily life. Only a limited number of experimental studies have performed quantitative measurements of olfactory abnormalities in ASD. Therefore, clarifying the relationship between olfactory traits and the influence of real-life situations in a laboratory setting is very difficult. Some new methodologies for measuring olfactory traits are gradually becoming available. New methods that reveal important links between ASD and olfactory traits should be developed in the future.