Network dynamics in the neural control of birdsong

Sequences of stereotyped actions are central to the everyday lives of humans and animals, from the kingfisher's dive to the performance of a piano concerto. Lashley asked how neural circuits managed this feat nearly 6 decades ago, and to this day it remains a fundamental question in neuroscience. Toward answering this question, vocal performance in the songbird was used as a model to study the performance of learned, stereotyped motor sequences. The first component of this work considers the song motor cortical zone HVC in the zebra finch, an area that sends precise timing signals to both the descending motor pathway, responsible for stereotyped vocal performance in the adult, and the basal ganglia, which is responsible for both motor variability and song learning. Despite intense interest in HVC, previous research has exclusively focused on describing the activity of small numbers of neurons recorded serially as the bird sings. To better understand HVC network dynamics, both single units and local field potentials were sampled across multiple electrodes simultaneously in awake behaving zebra finches. The local field potential and spiking data reveal a stereotyped spatio-temporal pattern of inhibition operating on a 30 ms time-scale that coordinates the neural sequences in principal cells underlying song. The second component addresses the resilience of the song circuit through cutting the motor cortical zone HVC in half along one axis. Despite this large-scale perturbation, the finch quickly recovers and sings a near-perfect song within a single day. These first two studies suggest that HVC is functionally organized to robustly generate neural dynamics that enable vocal performance. The final component concerns a statistical study of the complex, flexible songs of the domesticated canary. This study revealed that canary song is characterized by specific long-range correlations up to 7 seconds long-a time-scale more typical of human music than animal vocalizations. Thus, the neural sequences underlying birdsong must be capable of generating more structure and complexity than previously thought

Measuring consumer perceptions of credibility, engagement, interactivity and brand metrics of social network sites

For advertisers looking to include online media in their marketing strategies, consumer perceptions of Web sites become increasingly important. This study examined three types of endorsement in an online setting. To accommodate the many voices of a social network site, this study employed a new form of endorsement, a social-network endorsement, to account for the collective opinions and feedback of social network site members. Using an experimental design, this study tested the credibility, engagement, and interactivity of three types of endorsements: a corporate endorsement, a third-party endorsement and a social-network endorsement. Two hundred fifty-one participants examined one of three sites, a corporate site, a blog and a Facebook group page, to determine if Web site source affected credibility, engagement, interactivity, attitude toward the Web site, brand attitudes, and purchase intentions. Findings indicated consumers regard corporate Web sites with more credibility and find them more engaging and interactive. Credibility also increased positive attitudes towards the Web sites. Subjects also rated Facebook more trustworthy and engaging than the blog. However, none of the different endorsements influenced brand attitudes or purchase intentions

Enhancing Data Science Education throughout Indiana

Data science is the process of analyzing authentic real-world data sets to extract meaning, glean context, and seek insight into how to improve society. Data science promises new insights, helping transform information into knowledge that can drive science and industry (Berman et al., 2018). In recent years, employer demand for employees with the visualization, mathematical, and computational programming skill sets for this expanding niche has led to the introduction of new programs and coursework at both the K-12 and collegiate level. This research brief examines one such partnership in Indiana funded by the Lilly Endowment partnering Purdue University Fort Wayne (PFW) and the Fort Wayne Community Schools

Effects of Lightning on Trees: A Predictive Model Based on in situ Electrical Resistivity

The effects of lightning on trees range from catastrophic death to the absence of observable damage. Such differences may be predictable among tree species, and more generally among plant life history strategies and growth forms. We used field‐collected electrical resistivity data in temperate and tropical forests to model how the distribution of power from a lightning discharge varies with tree size and identity, and with the presence of lianas. Estimated heating density (heat generated per volume of tree tissue) and maximum power (maximum rate of heating) from a standardized lightning discharge differed 300% among tree species. Tree size and morphology also were important; the heating density of a hypothetical 10 m tall Alseis blackiana was 49 times greater than for a 30 m tall conspecific, and 127 times greater than for a 30 m tall Dipteryx panamensis. Lianas may protect trees from lightning by conducting electric current; estimated heating and maximum power were reduced by 60% (±7.1%) for trees with one liana and by 87% (±4.0%) for trees with three lianas. This study provides the first quantitative mechanism describing how differences among trees can influence lightning–tree interactions, and how lianas can serve as natural lightning rods for trees

Intellectual need and problem-free activity in the mathematics classroom

Intellectual need, a key part of the DNR theoretical framework, is posited to be necessary for significant learning to occur. This paper provides a theoretical examination of intellectual need and its absence in mathematics classrooms. Although this is not an empirical study, we use data from observed high school algebra classrooms to illustrate four categories of activity students engage in while feeling little or no intellectual need. We present multiple examples for each category in order to draw out different nuances of the activity, and we contrast the observed situations with ones that would provide various types of intellectual need. Finally, we offer general suggestions for teaching with intellectual need