We See Into the Life of Things

Pages 47-4

Quantifying Self Perception: Multisensory Temporal Asynchrony Discrimination As A Measure of Body Ownership

There are diffuse and distinct cortical networks involved in the various aspects of body representation that organize information from multiple sensory inputs and resolve conflicts when faced with incongruent situations. This coherence is typically maintained as we maneuver around the world, as our bodies change over the years, and as we gain experience. An important aspect of a congruent representation of the body in the brain is the visual perspective in which we are able to directly view our own body. There is a clear separation of the cortical networks involved in seeing our own body and that of another person. For the projects presented in my dissertation, I used an experimental design in which participants were required to make a multisensory temporal asynchrony discrimination after self-generated movements. I measured sensitivity for visual delay detection between the movement (proprioceptive, efferent and afferent information) and the visual image of that movement under differing visual, proprioceptive, and vestibular conditions. The self-advantage is a signature of body ownership and is characterized by a significantly lower threshold for delay detection for views of the body that are considered self compared to those that are regarded as other. Overall, the results from the collection of studies suggest that the tolerance for temporally matching visual, proprioceptive and efferent copy information that informs about the perceived position of body parts depends on: whether one is viewing ones own body or someone elses; the perspective in which the body is viewed; the dominant hand; and the reliability of vestibular cues which help us situate our body in space. Further, the self-advantage provides a robust measure of body ownership. The experiments provide a window on and support for the malleable nature of the representation of the body in the brain

“When in Rome”: identifying social norms using coordination games

Previous research in economics, social psychology, and sociology has produced compelling evidence that social norms influence behavior. In this paper we apply the Krupka and Weber (2013) norm elicitation procedure and present U.S. and non-U.S. born subjects with two scenarios for which tipping and punctuality norms are known to vary across countries. We elicit shared beliefs by having subjects match appropriateness ratings of different actions (such as arriving late or on time) to another randomly selected participant from the same university or to a participant who is born in the same country. We also elicit personal beliefs without the matching task. We test whether the responses from the coordination task can be interpreted as social norms by comparing responses from the coordination game with actual social norms (as identified using independent materials such as tipping guides for travelers). We compare responses elicited with the matching tasks to those elicited without the matching task to test whether the coordination device itself is essential for identifying social norms. We find that appropriateness ratings for different actions vary with the reference group in the matching task. Further, the ratings obtained from the matching task vary in a manner consistent with the actual social norms of that reference group. Thus, we find that shared beliefs correspond more closely to externally validated social norms compared to personal beliefs. Second, we highlight the importance that reference groups (for the coordination task) can play

Functional genomics and microbiome profiling of the Asian longhorned beetle (\u3ci\u3eAnoplophora glabripennis\u3c/i\u3e) reveal insights into the digestive physiology and nutritional ecology of wood feeding beetles

Background: Wood-feeding beetles harbor an ecologically rich and taxonomically diverse assemblage of gut microbes that appear to promote survival in woody tissue, which is devoid of nitrogen and essential nutrients. Nevertheless, the contributions of these apparent symbionts to digestive physiology and nutritional ecology remain uncharacterized in most beetle lineages. Results: Through parallel transcriptome profiling of beetle- and microbial- derived mRNAs, we demonstrate that the midgut microbiome of the Asian longhorned beetle (Anoplophora glabripennis), a member of the beetle family Cerambycidae, is enriched in biosynthetic pathways for the synthesis of essential amino acids, vitamins, and sterols. Consequently, the midgut microbiome of A. glabripennis can provide essential nutrients that the beetle cannot obtain from its woody diet or synthesize itself. The beetle gut microbiota also produce their own suite of transcripts that can enhance lignin degradation, degrade hemicellulose, and ferment xylose and wood sugars. An abundance of cellulases from several glycoside hydrolase families are expressed endogenously by A. glabripennis, as well as transcripts that allow the beetle to convert microbe-synthesized essential amino acids into non-essential amino acids. A. glabripennis and its gut microbes likely collaborate to digest carbohydrates and convert released sugars and amino acid intermediates into essential nutrients otherwise lacking from their woody host plants. Conclusions: The nutritional provisioning capabilities of the A. glabripennis gut microbiome may contribute to the beetles’ unusually broad host range. The presence of some of the same microbes in the guts of other Cerambycidae and other wood-feeding beetles suggests that partnerships with microbes may be a facilitator of evolutionary radiations in beetles, as in certain other groups of insects, allowing access to novel food sources through enhanced nutritional provisioning

Mother to offspring transmission of chronic wasting disease in Reeves' Muntjac deer

The horizontal transmission of prion diseases has been well characterized in bovine spongiform encephalopathy (BSE), chronic wasting disease (CWD) of deer and elk and scrapie of sheep, and has been regarded as the primary mode of transmission. Few studies have monitored the possibility of vertical transmission occurring within an infected mother during pregnancy. To study the potential for and pathway of vertical transmission of CWD in the native cervid species, we used a small cervid model-the polyestrous breeding, indoor maintainable, Reeves' muntjac deer-and determined that the susceptibility and pathogenesis of CWD in these deer reproduce that in native mule and white-tailed deer. Moreover, we demonstrate here that CWD prions are transmitted from doe to fawn. Maternal CWD infection also appears to result in lower percentage of live birth offspring. In addition, evolving evidence from protein misfolding cyclic amplification (PMCA) assays on fetal tissues suggest that covert prion infection occurs in utero. Overall, our findings demonstrate that transmission of prions from mother to offspring can occur, and may be underestimated for all prion diseases

Pubertal timing and breast density in young women: a prospective cohort study.

BACKGROUND:Earlier age at onset of pubertal events and longer intervals between them (tempo) have been associated with increased breast cancer risk. It is unknown whether the timing and tempo of puberty are associated with adult breast density, which could mediate the increased risk. METHODS:From 1988 to 1997, girls participating in the Dietary Intervention Study in Children (DISC) were clinically assessed annually between ages 8 and 17 years for Tanner stages of breast development (thelarche) and pubic hair (pubarche), and onset of menses (menarche) was self-reported. In 2006-2008, 182 participants then aged 25-29 years had their percent dense breast volume (%DBV) measured by magnetic resonance imaging. Multivariable, linear mixed-effects regression models adjusted for reproductive factors, demographics, and body size were used to evaluate associations of age and tempo of puberty events with %DBV. RESULTS:The mean (standard deviation) and range of %DBV were 27.6 (20.5) and 0.2-86.1. Age at thelarche was negatively associated with %DBV (p trend = 0.04), while pubertal tempo between thelarche and menarche was positively associated with %DBV (p trend = 0.007). %DBV was 40% higher in women whose thelarche-to-menarche tempo was 2.9 years or longer (geometric mean (95%CI) = 21.8% (18.2-26.2%)) compared to women whose thelarche-to-menarche tempo was less than 1.6 years (geometric mean (95%CI) = 15.6% (13.9-17.5%)). CONCLUSIONS:Our results suggest that a slower pubertal tempo, i.e., greater number of months between thelarche and menarche, is associated with higher percent breast density in young women. Future research should examine whether breast density mediates the association between slower tempo and increased breast cancer risk