What Do Eye Gaze Metrics Tell Us about Motor Imagery?

Many of the brain structures involved in performing real movements also have increased activity during imagined movements or during motor observation, and this could be the neural substrate underlying the effects of motor imagery in motor learning or motor rehabilitation. In the absence of any objective physiological method of measurement, it is currently impossible to be sure that the patient is indeed performing the task as instructed. Eye gaze recording during a motor imagery task could be a possible way to “spy” on the activity an individual is really engaged in. The aim of the present study was to compare the pattern of eye movement metrics during motor observation, visual and kinesthetic motor imagery (VI, KI), target fixation, and mental calculation. Twenty-two healthy subjects (16 females and 6 males), were required to perform tests in five conditions using imagery in the Box and Block Test tasks following the procedure described by Liepert et al. Eye movements were analysed by a non-invasive oculometric measure (SMI RED250 system). Two parameters describing gaze pattern were calculated: the index of ocular mobility (saccade duration over saccade + fixation duration) and the number of midline crossings (i.e. the number of times the subjects gaze crossed the midline of the screen when performing the different tasks). Both parameters were significantly different between visual imagery and kinesthesic imagery, visual imagery and mental calculation, and visual imagery and target fixation. For the first time we were able to show that eye movement patterns are different during VI and KI tasks. Our results suggest gaze metric parameters could be used as an objective unobtrusive approach to assess engagement in a motor imagery task. Further studies should define how oculomotor parameters could be used as an indicator of the rehabilitation task a patient is engaged in.     

What is the relationship between the global structures of apo and holo proteins?

It is well known that ligand binding and release may induce a wide range of structural changes in a receptor protein, varying from small movements of loops or side chains in the binding pocket to large‐scale domain hinge‐bending and shear motions or even partial unfolding that facilitates the capture and release of a ligand. An interesting question is what in general are the conformational changes triggered by ligand binding? The aim of this work is analyze the magnitude of structural changes in a protein resulting from ligand binding to assess if the state of ligand binding needs to be included in template‐based protein structure prediction algorithms. To address this issue, a nonredundant dataset of 521 paired protein structures in the ligand‐free and ligand‐bound form was created and used to estimate the degree of both local and global structure similarity between the apo and holo forms. In most cases, the proteins undergo relatively small conformational rearrangements of their tertiary structure upon ligand binding/release (most root‐mean‐square‐deviations from native, RMSD, are <1 Å). However, a clear difference was observed between single‐ and multiple‐domain proteins. For the latter, RMSD changes greater than 1 Å and sometimes larger were found for almost 1/3 of the cases; these are mainly associated with large‐scale hinge‐bending movements of entire domains. The changes in the mutual orientation of individual domains in multiple‐domain proteins upon ligand binding were investigated using a mechanistic model based on mass‐weighted principal axes as well as interface buried surface calculations. Some preferences toward the anticipated mechanism of protein domain movements are predictable based on the examination of just the ligand‐free structural form. These results have applications to protein structure prediction, particularly in the context of protein domain assembly, if additional information concerning ligand binding is exploited. Proteins 2008. © 2007 Wiley‐Liss, Inc.     

The “χ” of the Matter: Testing the Relationship between Paleoenvironments and Three Theropod Clades

The view of spinosaurs as dinosaurs of semi-aquatic habits and strongly associated with marginal and coastal habitats are deeply rooted in both scientific and popular knowledge, but it was never statistically tested. Inspired by a previous analysis of other dinosaur clades and major paleoenvironmental categories, here we present our own statistical evaluation of the association between coastal and terrestrial paleoenvironments and spinosaurids, along with other two theropod taxa: abelisaurids and carcharodontosaurids. We also included a taphonomic perspective and classified the occurrences in categories related to potential biases in order to better address our interpretations. Our main results can be summarized as follows: 1) the taxon with the largest amount of statistical evidence showing it positively associated to coastal paleoenvironments is Spinosauridae; 2) abelisaurids and carcharodontosaurids had more statistical evidence showing them positively associated with terrestrial paleoenvironments; 3) it is likely that spinosaurids also occupied spatially inland areas in a way somehow comparable at least to carcharodontosaurids; 4) abelisaurids may have been more common than the other two taxa in inland habitats.     

The Relationship between Respiration-Related Membrane Potential Slow Oscillations and Discharge Patterns in Mitral/Tufted Cells: What Are the Rules?

Background

A slow respiration-related rhythm strongly shapes the activity of the olfactory bulb. This rhythm appears as a slow oscillation that is detectable in the membrane potential, the respiration-related spike discharge of the mitral/tufted cells and the bulbar local field potential. Here, we investigated the rules that govern the manifestation of membrane potential slow oscillations (MPSOs) and respiration-related discharge activities under various afferent input conditions and cellular excitability states.

Methodology and Principal Findings

We recorded the intracellular membrane potential signals in the mitral/tufted cells of freely breathing anesthetized rats. We first demonstrated the existence of multiple types of MPSOs, which were influenced by odor stimulation and discharge activity patterns. Complementary studies using changes in the intracellular excitability state and a computational model of the mitral cell demonstrated that slow oscillations in the mitral/tufted cell membrane potential were also modulated by the intracellular excitability state, whereas the respiration-related spike activity primarily reflected the afferent input. Based on our data regarding MPSOs and spike patterns, we found that cells exhibiting an unsynchronized discharge pattern never exhibited an MPSO. In contrast, cells with a respiration-synchronized discharge pattern always exhibited an MPSO. In addition, we demonstrated that the association between spike patterns and MPSO types appeared complex.

Conclusion

We propose that both the intracellular excitability state and input strength underlie specific MPSOs, which, in turn, constrain the types of spike patterns exhibited.     

The production of “bacteria-free” mice. Relationship between fecal flora and bacterial population of the skin

In mice, after a few days of oral treatment with antibiotics which are minimally absorbed, the bacterial fecal flora is eliminated. In the course of such treatment, the bacterial population of the skin becomes drastically reduced. After 9 weeks, cultures from the skin of the back are negative. Following 12 weeks of treatment, about 50% of the mice are shown to be persistently free of microbes that are detectable by conventional methods of culturing.Disinfection of the skin (chlorhexidine) on the fourth day of treatment had no effect on the time required to obtain negative whole-body cultures in these animals.We are indebted to Mrs. J. E. C. Lekkerkerk for skilful aid in the bacteriological evaluation of the samples and to Mr. W. Aarssen for assistance in the maintenance of the mice.     

Relationship between the Autoantibody and Expression of β3-Adrenoceptor in Lung and Heart

Background

Evidences suggest that β₃ -adrenoceptor (β₃-AR) plays an important role in heart failure (HF), although no data is reported indicating how these effects may change with the increasing age. Pulmonary congestion and edema are the major life-threatening complications associated with HF. The purpose of this study is to explore the relationship between the anti-β₃-AR autoantibody and the expression of β₃-AR in the lungs and heart for both aged patients and rats with HF.

Methods

Synthetic β₃-AR peptides served as the target antigens in ELISA were used to screen the anti-β₃-AR autoantibody in aged patients and rats. Two aged rat models were constructed based on aortic banding and sham-operation. The expression of β₃-AR mRNA and protein in the lung and heart was measured in intervention and non-intervention groups by Western blot analysis at the baseline, 5^th, 7^th, 9^th and 11^th week, respectively.

Results

The frequency and titer of anti-β₃-AR autoantibody in aged patients and rats with HF were higher than those in the control group (p<0.05). The expression of β₃-AR mRNA and protein in pulmonary tissues decreased continually from the 7^th week (p<0.05), followed by HF observed during the 9^th week. The expression of β₃-AR in myocardial tissues continued to increase after the 9^th week (p<0.05), and the expression of both β₃-AR mRNA and protein in the BRL group [HF group with BRL37344 (4-[-[2-hydroxy-(3-chlorophenyl)ethyl-amino] phenoxyacetic acid) (a β₃-AR agonist) injection] was positively correlated with BRL37344 when compared with non-BRL group (HF group without BRL37344 injection) (p<0.05).

Conclusion

Anti-β₃-AR autoantibody was detected in aged patients and rats with HF. The expression of β₃-AR mRNA and protein in pulmonary tissues decreased continually, and began earlier than in the heart, but its expression in myocardial tissues increased continually and could be further promoted by β₃-AR agonist.     

Do the evolutionary interactions between moths and bats promote niche partitioning between bats and birds?

Ecological theory suggests that the coexistence of species is promoted by the partitioning of available resources, as in dietary niche partitioning where predators partition prey. Yet, the mechanisms underlying dietary niche partitioning are not always clear. We used fecal DNA metabarcoding to investigate the diets of seven nocturnal insectivorous bird and bat species. Low diet overlap (2%–22%) supported resource partitioning among all species. Differences in diet corresponded with species identity, prey detection method, and foraging behavior of predators. Insects with ultrasonic hearing capabilities were consumed significantly more often by birds than bats, consistent with an evolved avoidance of echolocating strategies. In turn, bats consumed a greater proportion of noneared insects such as spruce budworms. Overall, our results suggest that evolutionary interactions among bats and moths translate to dietary niche partitioning and coexistence among bats and nocturnal birds.     

γ-Activity of the cerebral cortex: Relationship between intelligence and the accuracy of time perception

Relationships of the indices of intelligence and the accuracy of time perception with the level of cortical interactions in the γ frequency band, as well as the phase ratios between the γ rhythm and low-frequency EEG components have been established. The pattern of these relationships are different in young men and women and depends on the frequency range of the γ rhythm, as well as the type and stage of the activity performed by the subjects.     

What determines the relationship between plant diversity and habitat productivity?

The relationship between biodiversity and habitat productivity has been a fundamental topic in ecology. Although the relationship between these parameters may exhibit different shapes, the unimodal shape has been frequently encountered. The decrease in diversity at high productivity has usually been attributed to competitive exclusion. We suggest that evolutionary history and dispersal limitation may be even more important in shaping the diversity–productivity relationship. On a global scale, unimodal diversity–productivity relationships dominate in temperate regions, whereas positive relationships are more common in the tropics. This difference can be accounted for by contrasting evolutionary history. Temperate regions have smaller species pools for productive habitats since these habitats have been scarce historically for speciation, while the opposite is true for the tropics. In addition, dispersal within a region may limit diversity either due to the lack of dispersal syndromes at low productivity or the low number of diaspores at high productivity. Thereafter, biotic interactions (competition and facilitation) can shape the relationship. All these processes can act independently or concurrently. We recommend that the common approach to examining empirical diversity–environmental relationships should start with the role of large‐scale processes such as evolutionary history and dispersal limitation, followed by influences associated with ecological interactions.     

Do qualifiers of ASCUS distinguish between low- and high-risk patients?

OBJECTIVE: To evaluate the qualification of a Pap smear classified as atypical squamous cells of undetermined significance (ASCUS) favor reactive or neoplasia as recommended by the Bethesda System. STUDY DESIGN: The smears from 105 concurrent patients with a cytologic diagnosis of ASCUS not otherwise qualified were reviewed and subclassified as ASCUS favor reactive, low grade squamous intraepithelial lesion (LSIL) or high grade squamous intraepithelial lesion (HSIL) based on the Bethesda System criteria. The cervical biopsy diagnoses were correlated. RESULTS: Of the 105 cases classified as ASCUS, 37 were subclassified as favor reactive, 51 as favor LSIL and 17 as favor HSIL on cytologic review. In the ASCUS favor reactive group, 19 (51%) had reactive changes on biopsy, 17 (46%) had cervical intraepithelial neoplasia (CIN) 1, and 1 (2%) had CIN 3. A total of 48% patients had CIN. In the favor LSIL group, there was CIN 1 in 28 cases (55%), CIN 2 or 3 in 12 (23%) and benign changes in 11 (22%) on biopsy. Seventy-eight percent had CIN. In the 17 cases classified as ASCUS favor HSIL group, all had CIN. CONCLUSION: Of the total 105 cases of ASCUS, 71% had CIN, 29% had reactive changes on follow-up biopsies, and 48% of patients in the ASCUS favor reactive group had CIN. Qualifiers of ASCUS have questionable utility in patient management.     

Who Tweets with Their Location? Understanding the Relationship between Demographic Characteristics and the Use of Geoservices and Geotagging on Twitter

In this paper we take advantage of recent developments in identifying the demographic characteristics of Twitter users to explore the demographic differences between those who do and do not enable location services and those who do and do not geotag their tweets. We discuss the collation and processing of two datasets—one focusing on enabling geoservices and the other on tweet geotagging. We then investigate how opting in to either of these behaviours is associated with gender, age, class, the language in which tweets are written and the language in which users interact with the Twitter user interface. We find statistically significant differences for both behaviours for all demographic characteristics, although the magnitude of association differs substantially by factor. We conclude that there are significant demographic variations between those who opt in to geoservices and those who geotag their tweets. Not withstanding the limitations of the data, we suggest that Twitter users who publish geographical information are not representative of the wider Twitter population.     

Relationship between the structures of flavonoids and their NF-κB-dependent transcriptional activities

It has been previously shown that some flavonoids inhibit NF-κB; however, the structure-activity relationships between chalcone, flavanone, flavone, and isoflavone derivatives and their TNFα induced NF-κB inhibitory effects on HCT116 human colon cancer cells have not yet been reported. Therefore, in this study, the effects of flavonoid structure on inhibition of NF-κB were investigated. Based on the combined results of this study, the structure of the flavonoids was shown to affect NF-κB activation.     

Do American Crows Pay Attention to Human Gaze and Facial Expressions?

Interactions between species can lead to the evolution of interspecific communication. Non‐verbal communication by humans, both intentional and unintentional, can be interpreted by other species. We tested whether American crows (Corvus brachyrhynchos) were sensitive to human facial features under field conditions by comparing flight initiation distances and urgency of escape behavior to human approaches varying in eye contact and facial expression. We first examined whether crows distinguish between an approaching human who is directly gazing at them and a human approaching them with an averted gaze. In a second experiment, we tested whether crows differentiate a smiling from scowling human approaching them with direct or averted gaze. In the first experiment, we found that crows fled sooner and more urgently when humans were directly gazing at them. Similarly, in the second experiment, crows responded sooner to a direct vs. averted gaze; however, they did not react differently to varying human facial expressions. We suggest that crows use human gaze as a reliable visual cue compared with facial expressions when making decisions about responding to approaching humans. This is the first study to show that a wild corvid species changes its behavior based on human gaze, possibly representing an adaptation to living in human‐dominated urban areas and suggesting crows might perceive human intention by this visual cue.     

Inference or Enaction? The Impact of Genre on the Narrative Processing of Other Minds

Do narratives shape how humans process other minds or do they presuppose an existing theory of mind? This study experimentally investigated this problem by assessing subject responses to systematic alterations in the genre, levels of intentionality, and linguistic complexity of narratives. It showed that the interaction of genre and intentionality level are crucial in determining how narratives are cognitively processed. Specifically, genres that deployed evolutionarily familiar scenarios (relationship stories) were rated as being higher in quality when levels of intentionality were increased; conversely, stories that lacked evolutionary familiarity (espionage stories) were rated as being lower in quality with increases in intentionality level. Overall, the study showed that narrative is not solely either the origin or the product of our intuitions about other minds; instead, different genres will have different—even opposite—effects on how we understand the mind states of others.     

The role of the anticodon in the interaction between methionyl-tRNA synthetase and bacterial initiator tRNA?

Complementary and antiparallel oligonucleotides bind to exposed regions of the tRNA molecule. Aminoacylation in the presence of triplets has been used to determine the role of the anticodon in the interaction between methionyl-tRNA synthetase and initiator tRNA. ApUpG has no effect on the charging even when 70% of the tRNA is bound to the triplet, whereas in the presence of GpGpU which binds to the A-C-C sequence adjacent to the 3' terminal adenosine that fraction of the tRNA which is bound to the triplet is completely unavailable for charging. Hence the anticodon is probably not involved in a primary interaction while the A-C-C-A-OH clearly is. This conclusion is supported by the failure of the isolated anticodon loop and stem oligonucleotides to inhibit the aminoacylation reaction.     

Relationship between kinetic properties of γ-glutamyl transpeptidase and the structure of its saccharide moiety

Gamma-glutamyl transpeptidase (EC 2.3.2.2; GGT) is a plasma-membrane bound glycoenzyme, the saccharide moiety of which is rather heterogeneous and organ specific. It has been stated that GGT catalyses three types of reactions, i.e., hydrolysis, transpeptidation and autotranspeptidation. The initial velocity equation, involving all these reactions, is shown in the present report. Mathematical analysis of the equation resulted in a. definition of the constant of half saturation (K_hs). The value of K_hs was used for characterization of kinetics of GGT from rat organs differing in the structure of GGT oligosaccharide chains. No significant organ differences were found, when the K_hs values of GGT from the brain, kidney and pancreas equalled 0.61 mM, 0.68 mM and 0.68 mM, respectively. On the contrary, when two different glycoforms of GGT from the pancreas were compared, distinct values of K_hs were obtained (l.43 mM and 0.67 mM, respectively). It is therefore being suggested that the saccharide chains of GGT are involved in its kinetic properties. However, this effect is masked when the enzyme, non-fractionated into glycoforms, is analysed, even though the saccharide moiety is specific for the organ studied.