Preserved neural dynamics across animals performing similar behaviour

Animals of the same species exhibit similar behaviours that are advantageously adapted to their body and environment. These behaviours are shaped at the species level by selection pressures over evolutionary timescales. Yet, it remains unclear how these common behavioural adaptations emerge from the idiosyncratic neural circuitry of each individual. The overall organization of neural circuits is preserved across individuals1 because of their common evolutionarily specified developmental programme2-4. Such organization at the circuit level may constrain neural activity5-8, leading to low-dimensional latent dynamics across the neural population9-11. Accordingly, here we suggested that the shared circuit-level constraints within a species would lead to suitably preserved latent dynamics across individuals. We analysed recordings of neural populations from monkey and mouse motor cortex to demonstrate that neural dynamics in individuals from the same species are surprisingly preserved when they perform similar behaviour. Neural population dynamics were also preserved when animals consciously planned future movements without overt behaviour12 and enabled the decoding of planned and ongoing movement across different individuals. Furthermore, we found that preserved neural dynamics extend beyond cortical regions to the dorsal striatum, an evolutionarily older structure13,14. Finally, we used neural network models to demonstrate that behavioural similarity is necessary but not sufficient for this preservation. We posit that these emergent dynamics result from evolutionary constraints on brain development and thus reflect fundamental properties of the neural basis of behaviour

LookOut! Interactive Camera Gimbal Controller for Filming Long Takes

The job of a camera operator is more challenging, and potentially dangerous, when filming long moving camera shots. Broadly, the operator must keep the actors in-frame while safely navigating around obstacles, and while fulfilling an artistic vision. We propose a unified hardware and software system that distributes some of the camera operator's burden, freeing them up to focus on safety and aesthetics during a take. Our real-time system provides a solo operator with end-to-end control, so they can balance on-set responsiveness to action vs planned storyboards and framing, while looking where they're going. By default, we film without a field monitor. Our LookOut system is built around a lightweight commodity camera gimbal mechanism, with heavy modifications to the controller, which would normally just provide active stabilization. Our control algorithm reacts to speech commands, video, and a pre-made script. Specifically, our automatic monitoring of the live video feed saves the operator from distractions. In pre-production, an artist uses our GUI to design a sequence of high-level camera "behaviors." Those can be specific, based on a storyboard, or looser objectives, such as "frame both actors." Then during filming, a machine-readable script, exported from the GUI, ties together with the sensor readings to drive the gimbal. To validate our algorithm, we compared tracking strategies, interfaces, and hardware protocols, and collected impressions from a) film-makers who used all aspects of our system, and b) film-makers who watched footage filmed using LookOut.Comment: V2: - Fixed typos. - Cleaner supplemental. - New plot in control section with same data from a supplemental vide

Structure-from-motion in Spherical Video using the von Mises-Fisher Distribution

In this paper, we present a complete pipeline for computing structure-from-motion from the sequences of spherical images. We revisit problems from multiview geometry in the context of spherical images. In particular, we propose methods suited to spherical camera geometry for the spherical-n-point problem (estimating camera pose for a spherical image) and calibrated spherical reconstruction (estimating the position of a 3-D point from multiple spherical images). We introduce a new probabilistic interpretation of spherical structure-from-motion which uses the von Mises-Fisher distribution to model noise in spherical feature point positions. This model provides an alternate objective function that we use in bundle adjustment. We evaluate our methods quantitatively and qualitatively on both synthetic and real world data and show that our methods developed for spherical images outperform straightforward adaptations of methods developed for perspective images. As an application of our method, we use the structure-from-motion output to stabilise the viewing direction in fully spherical video

HYDRODYNAMICS OF FRESHWATER TURTLES: MANEUVERABILITY, STABILITY, AND EFFECTS OF SHELL SHAPE

Aquatic organisms exhibit tremendous diversity in body design and modes of propulsion that can strongly influence locomotor performance. Understanding how such differences affect locomotor performance is a major focus of research in integrative organismal biology and can provide insight into the evolutionary origins of such variation. Turtles are unique among extant tetrapods (i.e., amphibians, reptiles, birds, and mammals) in that they possess rigid bodies. In turtles, the vertebrae are fused dorsally with a bony carapace, precluding movement of the axial skeleton between the base of the neck and the tail. As a result of their immobilized axial skeleton and reduced tail, thrust in swimming turtles is generated exclusively by the movements of fore- and hind-limbs. Despite the potential constraints of a rigid body on locomotion in turtles, over 100 extant species inhabit aquatic environments. Moreover, these turtles display considerable variation in shell and propulsor morphology and have evolved two different modes of propulsion (four-limbed rowing vs. forelimb flapping). My dissertation is a collection of three studies that examined the interaction between morphology and hydrodynamic performance (maneuverability, stability, and drag) in freshwater turtles. First, I described the patterns of limb movements used to produce turns and quantified turning performance, comparing results to that of other rigid- and flexible-bodied animals. Second, I assessed kinematics and hydrodynamic stability during straight-line swimming. I also compared data I collected from freshwater turtles to previous data collected from two species of sea turtles to assess how the different modes of propulsion used by the two groups affect stability. Finally, I examined the relationship between habitat (environmental flow regime), morphology (shell shape), and performance (hydrodynamic drag) among intraspecific populations of the large riverine turtle Pseudemys concinna. Specially, I tested for three-dimensional differences in shell shape between turtles from slow- and fast-flowing habitats, while concomitantly testing whether the carapace and plastron demonstrate the same propensity for environmentally correlated differences. I also used physical models to test whether morphological differences of the shell confer reductions in drag, and provide preliminary data regarding the potential role of phenotypic plasticity in generating the morphological variation observed in turtles between the two flow regimes. Data from these studies provides insight into the evolutionary origins of intra- and inter-specific variation in shell shape

CONSTRAINTS OF THE IMAGINATION: HOW PHENOTYPES ARE SHAPED THROUGH GENETICS, THE ENVIRONMENT, AND DEVELOPMENT

Phenotypic constraints are ubiquitous throughout nature, being found throughout all stages of life and at multiple different biological levels including cellular, genetic, environmental, behavioral, evolutionary, and developmental. These constraints have shaped, not only the natural world, but the way that we perceive what is possible, or impossible, an observation made clear by François Jacob in his 1977 paper “Evolution and Tinkering”. This is reflected in the literature, repeatedly, by the regular occurrence of densely packed visualization of phenotypic space that seemingly always have large areas that go unoccupied. Despite constrained regions of space being observable across countless taxa, identifying the mechanisms of those constraints remains elusive. Given that constraints are widespread and have influenced how evolution may work, my aim was to identify mechanisms of constraint throughout multiple biological levels. Chapter one is divided into two parts, sections A and B, but largely focuses on how constraints are influenced by genetics. For this, we investigated crocc2, a protein that encodes for a structural component of the ciliary rootlet which in turn plays a major role as a mechanosensory for nearly all cells. We found dysfunctional crocc2 resulted in both dysmorphic bone development and a decrease in the plastic response potential of zebrafish (section A), as well as altered developmental trajectories in juvenile morphology, presumably due to alterations in cellular polarity and inadequate extracellular communication. Importantly, all results from this chapter point toward crocc2 play a canalizing role in the production of phenotypes at multiple life-history stages. Chapter 2 takes a different approach into understanding constrains by looking at broad ecological alterations and how those alterations may alter morphology of resident taxa. Here, we utilized the heavily altered habitat of the Tocantins River in the Amazon and the existing museum collections to evaluate how select representatives of the cichlid community had responded to such change. We found significant changes in contemporary morphology across all included cichlid species compared to their historical counterparts. These data show that alterations to the environment have resulted in changes to the local resident species, and possibly an alteration to their future evolutionary trajectories. Among the species included, one was found to have the most substantial morphological changes, which is what we followed up in the next chapter. Chapter 3 dug into the morphological changes of Satanoperca, a Geophagine cichlid with a unique feeding mechanism known as winnowing. Winnowing is a poorly understood mechanical process involving substrate manipulation. Given that anthropogenic alterations to local hydrology oft result in changes to the benthic sediment composition, we wanted to know if differing substrates was enough to induce a plastic response in winnowing fishes, and if so which traits were effected. We found significant differences across our experimental populations in both shape and disparity and present evidence in support of wide-spread integration across craniofacial traits. In addition, these data suggest that the novel anatomical structure, the epibranchial lobe, is more modular than other craniofacial traits involved in the winnowing process. Chapters 4 and 5 utilize a unique lineage of fishes, the Bramidae, to understand how developmental and evolutionary constraints are broken to produce morphological novelties. We used a combination of DNA sequences from GenBank and numerous museum specimens to illuminate constraints and determine how constraints are broken to produce complex phenotypic novelties. In Chapter 4, we found that the fanfishes had experienced greater rates of morphological evolution than other members of the Bramidae family, resulting in their occupation of an entirely novel region of phenotypic space. In Chapter 5, we elaborated on this by investigating the developmental processes involved in producing an extreme morphological novelty. The data presented in Chapter 5 provide evidence suggesting that the fanfishes have broken various constraints, resulting in prominent anatomical and morphological changes to accommodate their novel phenotype. In all, my dissertation provides examples of how constraints have shaped the variability that we see throughout life and shows examples of how constraints can be identified, what happens when they are broken, and how they work to control the pace and trajectory of evolutionary processes

Morphological and Behavioral Traits Associated with Locomotion in Lizards

Morphology, locomotion, and behavior are co-adapted to optimize performance and ultimately fitness. Successfully navigating a complex environment is dictated by an animal’s locomotor behavior, and for some behaviors, its locomotor performance. The locomotor performance of an organism is directly related to the form and function of the structures involved in locomotion such that movement is efficient – that is, minimal loss of energy. The first chapter of this thesis focuses on the effects of obstacle placement and forelimb position on facultative bipedalism. Placing an obstacle beyond a lizard’s acceleration threshold did not affect the frequency of bipedal posture. Furthermore, the forelimb position of streamlined species is stereotyped during bipedal running, whereas the forelimb positions are varied in short stocky species. The second chapter investigates shape variation in the scapula among Phrynosomatid lizards across a gradient of species that vary in the use of horizontal to vertical locomotor planes. I determined that while global scapula shape is relatively conserved among lizards, localized changes occur at the muscle attachment sites used in vertical vs. horizontal locomotion. Furthermore, scapular shape in relation to habitat use is phylogenetically conserved with the exception of some Sceloporus species which diverged independently towards terrestrial locomotion

Vowel Production in Down Syndrome: An Ultrasound Study

The present study investigated the articulatory and acoustic characteristics of vowel production in individuals with Down syndrome (DS). Speech production deficits and reduced intelligibility are consistently noted in this population, attributed to any combination of phonological, structural, and/or motor control deficits. Speakers with DS have demonstrated impaired vowel production, as indicated by perceptual, acoustic, and articulatory data, with emerging evidence of vowel centralization. Participants in the study included eight young adults with DS, as well as eight age- and gender-matched controls. Ultrasound imaging was utilized to obtain midsagittal tongue contours during single-word productions, specifically targeting the corner vowels /ɑ/, /æ/, /i/, and /u/. Measurements of tongue shape, as related to its curvature and vowel differentiation, were calculated and contrasted between the participant groups. Acoustic measures of vowel centralization and variability of production were applied to concurrent vowel data. Single-word intelligibility testing was also conducted for speakers with DS, to obtain intelligibility scores and for analysis of error patterns. Results of the analyses demonstrated consistent differentiation for low vowel production between the two speaker groups, across both articulatory and acoustic measures. Speakers with DS exhibited reduced tongue shape curvature and/or complexity of low vowels /ɑ/ and /æ/, and high-vowel /u/, than did TD speakers, as well as some evidence of reduced differentiation between tongue shapes of all four corner vowels. Acoustic analysis revealed a lack of group differentiation across some metrics of vowel centralization, while a reduction in acoustic space dispersion from a centroid was demonstrated for the low vowels in speakers with DS. Increased variability of acoustic data was also noted among speakers in the DS group in comparison to TD controls. Single-word intelligibility scores correlated strongly with measures of acoustic variability among speakers with DS, and moderately with measures of articulatory differentiation. Clinical implications, as related to understanding the nature of the impairment in DS and effective treatment planning, are discussed

Aerial Vehicles

This book contains 35 chapters written by experts in developing techniques for making aerial vehicles more intelligent, more reliable, more flexible in use, and safer in operation.It will also serve as an inspiration for further improvement of the design and application of aeral vehicles. The advanced techniques and research described here may also be applicable to other high-tech areas such as robotics, avionics, vetronics, and space