The effects of yoked prisms on body posture and egocentric perception in a normal population

The principal theme of this thesis is the effect of yoked prisms on body posture and egocentric perception. Yoked prisms have been clinically used in the management of a variety of visual and neuro-motor dysfunctions. Most studies have been conducted in pathological populations by studying the effects of prismatic adaptation, without distinguishing short and long term effects. In this study, postural and perceptual prismatic effects have been studied by preventing prism adaptation. A healthy population was selected in order to investigate the immediate prismatic effects, when there is no obvious benefit from their use for the individual. Posturography was used to assess changes in weight distribution and shifts in centre of pressure (barycentre). In addition, photographic analyses were used to assess effects on posture on the x and z axis. Experiments with space board and visual midline shift were used for the evaluation of spatial perception and egocentric localisation. One pair of 8 Δ yoked prisms base left (BL) and one pair of 8 Δ yoked prisms base up (BU) were applied randomly and compared to a pair of plano lenses. Results suggest that immediate prismatic effects take place on a perceptual level and are reflected on an altered body posture respectively without significant changes in weight distribution. Yoked prisms BL showed a rightward rotational effect on spatial perception by expanding space on the z axis when viewing through the base of the prism and constricting space through the apex of the prism. Body posture responded respectively to what was visually perceived by altering posture. A rightward shift and tilt of the head was recorded along with the hips shift and shoulders tilt in the dame direction. Additionally, right shoulder shifted backwards and an angular midline shift to the right was recorded. The egocentric localisation was affected by shifting the midline perception to the left. Yoked prisms BU resulted on a head shift forward and a reduction of the head-neck angle by bringing the chin closer to the chest. The egocentric localisation was altered on the vertical axis providing subjects the perception that their eye level was higher during the experiment. In conclusion, yoked prisms seemed to induce changes in body posture, mainly in the upper body and head, without any significant changes in weight distribution. These changes are partially reflected in spatial perception tests and egocentric localisation before any prismatic adaptation takes place

Aperture Crossing in Challenging Environments: An Examination of the Factors that Influence the Passability of Narrow Spaces

In order to get to where we need to go, locomotion often involves walking through narrow spaces. Whether an aperture affords passage is thought to be determined by the body size/aperture size relationship. For normal, ground-level aperture crossing, spaces 1.3x the shoulder width or smaller are considered impassible (requiring a shoulder rotation) and as such, 1.3x SW is said to be the critical point of aperture crossing. However, daily activities often involve navigating through apertures under more challenging circumstances, such as when walking through a busy airport while carrying luggage. As such, additional factors other than simply the body size and the aperture size may contribute to whether an aperture is deemed passable. Therefore, the purpose of this thesis was to investigate how the factors associated with challenging environments contribute to the way in which the body-environment relationship determines the affordance of aperture crossing. Through a series of experiments, participants walked through apertures: 1) while carrying a wide object, 2) under conditions of increased postural threat, 3) where the narrow spaces were created by other individuals, and 4) where there were multiple, misaligned apertures. In general, aperture crossing behaviour was monitored through the frequency and magnitude of shoulder rotations at time-of-crossing (TOC), the critical point, the amount of space between the shoulders and the obstacles at TOC (spatial margin), the position of the body relative to midline (M-L COM at TOC) and the walking speed leading up to and crossing through the aperture (approach velocity and velocity at TOC). The results from study one reveal that the passability of apertures adapts to objects being carried by rescaling the body-environment relationship to consider the new person-plus-object width and maintaining a critical point of 1.3x the widest dimension. However, this rescaling occurred at different rates across individuals. Studies two and three demonstrate that action capabilities (postural threat) and characteristics of the aperture (people instead of poles) alter the passability of apertures, as evident by more cautious crossing behaviours. Specifically, individuals maintained a larger critical point, a higher frequency and larger magnitude of rotation, as well as a slower approach velocity and velocity at TOC. Lastly in study four, rather than walk through the center of an aperture and equalize the size of the spatial margin of each shoulder (as observed in single aperture crossing), individuals walking through multiple misaligned apertures reduce the size of the spatial margin by walking closer to the object nearest midline. Furthermore, participants choose to rotate their shoulders at apertures that would not normally require a rotation, likely in an attempt to maintain the straightest possible walking path. Together, these studies suggest that additional factors other than the body size/aperture size ratio are considered when determining the affordance of aperture crossing. Specifically, in addition to supporting the idea that individual abilities are an important contributing factor to the identification of affordances, these results demonstrate that the affordance of aperture crossing is influenced by: 1) the level of postural threat, 2) characteristics of the aperture, and 3) the number and position of apertures. Understanding the typical behaviour for walking through narrow spaces and knowing what and how specific factors influence the passability of apertures provides the necessary groundwork for understanding how these behaviours are altered with age or disease and can provide insightful suggestions for the future design of cluttered environments

Cognición y representación interna de entornos dinámicos en el cerebro de los mamíferos

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Biológicas, leída el 07/05/2021El tiempo es una de las dimensiones fundamentales de la realidad. Paradójicamente, los fenómenos temporales del mundo natural contienen ingentes cantidades de información redundante, y a pesar de ello, codificar internamente el tiempo en el cerebro es imprescindible para anticiparse a peligros en ambientes dinámicos. No obstante, dedicar grandes cantidades de recursos cognitivos a procesar las características espacio-temporales de entornos complejos debería ser incompatible con la supervivencia, que requiere respuestas rápidas. Aun así, los animales son capaces de tomar decisiones en intervalos de tiempo muy estrechos. ¿Cómo consigue hacer esto el cerebro? Como respuesta al balance entre complejidad y velocidad, la hipótesis de la compactación del tiempo propone que el cerebro no codifica el tiempo explícitamente, sino que lo integra en el espacio. En teoría, la compactación del tiempo simplifica las representaciones internas del entorno, reduciendo significativamente la carga de trabajo dedicada a la planificación y la toma de decisiones. La compactación del tiempo proporciona un marco operativo que pretende explicar cómo las situaciones dinámicas, percibidas o producidas, se representan cognitivamente en forma de predicciones espaciales o representaciones internas compactas (CIR), que pueden almacenarse en la memoria y recuperarse más adelante para generar respuestas. Aunque la compactación del tiempo ya ha sido implementada en robots, hasta ahora no se había comprobado su existencia como mecanismo biológico y cognitivo en el cerebro...Time is one of the most prominent dimensions that organize reality. Paradoxically, there are loads of redundant information contained within the temporal features of the natural world, and yet internal coding of time in the brain seems to be crucial for anticipating time-changing, dynamic hazards. Allocating such significant brain resources to process spatiotemporal aspects of complex environments should apparently be incompatible with survival, which requires fast and accurate responses. Nonetheless, animals make decisions under pressure and in narrow time windows. How does the brain achieve this? An effort to resolve the complexity-velocity trade-off led to a hypothesis called time compaction, which states the brain does not encode time explicitly but embeds it into space. Theoretically, time compaction can significantly simplify internal representations of the environment and hence ease the brain workload devoted to planning and decision-making. Time compaction also provides an operational framework that aims to explain how perceived and produced dynamic situations are cognitively represented, in the form of spatial predictions or compact internal representations (CIRs) that can be stored in memory and be used later on to guide behaviour and generate action. Although successfully implemented in robots, time compaction still lacked assessment of its biological soundness as an actual cognitive mechanism in the brain...Fac. de Ciencias BiológicasTRUEunpu

Using Reflexive Photography to Investigate Design Affordances for Creativity in Digital Entertainment Games

This article aims to provide an account of the use of reflexive photography in capturing player creativity in practice and present a guide to how game design can support player creativity. While previous literature has examined some aspects of player creativity in digital games, there remains a dearth of work, which examines how design elements of games contribute to creative behavior. Using a reflexive photography method with photo-elicitation interviews, this study identifies eight design affordances for player creativity in digital games and outlines the effectiveness of the reflexive photography method within the context of digital games. The identified design affordances related to the degree of flexibility of the game structure (e.g., open versus linear), narrative exploration, extent and diversity of game variables, opportunities for content creation, environmental interaction and exploration, avatar customization, progression, and replayability. Implications for the design of games that support creativity are discussed

The nature of culture : an eight-grade model for the evolution and expansion of cultural capacities in hominins and other animals

Tracing the evolution of human culture through time is arguably one of the most controversial and complex scholarly endeavors, and a broad evolutionary analysis of how symbolic, linguistic, and cultural capacities emerged and developed in our species is lacking. Here we present a model that, in broad terms, aims to explain the evolution and portray the expansion of human cultural capacities (the EECC model), that can be used as a point of departure for further multidisciplinary discussion and more detailed investigation. The EECC model is designed to be flexible, and can be refined to accommodate future archaeological

The influence of attentional focus on neuroplasticity following a seven-day balance training intervention

It is well established that focusing on the external effect of one’s movement (an external focus of attention) results in enhanced motor learning and produces superior motor performance compared to focusing inward on the body’s own physical execution of the motor movement (an internal focus). While the benefits of an external focus in motor learning, and the detriments of an inward or ‘internal’ focus have been highly replicated, there is still little mechanistic understanding pertaining to the brain-related changes that may result from these two different foci of attention during motor training. Since the brain is highly malleable and has been shown to adapt in response to motor training (i.e., neuroplasticity), it is postulated that attentional focus may change the brain’s structure and function. However, no direct examination exploring the influence of attentional focus on neuroplasticity (structural or functional) exists. The primary objective of this study was to determine the effects of balance training with different attentional foci on brain-related neuroplasticity in a young healthy population. Participants (n = 33) were randomly assigned to a control, internal focus, or external focus condition. Functional and structural brain connectivity analyses was conducted using neuroimaging data collected through functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) prior to (baseline) and following a seven-day balance training intervention (retention). Between baseline and retention data collection, participants in the internal and external focus training groups practiced a dynamic balance task for one hour per day, each day for seven consecutive days (acquisition). For the internal focus trials, participants were asked to, ‘focus on keeping their feet level;’ whereas, for the external focus trials participants were asked to, ‘focus on keeping the board level.’ The control group did not complete any balance training, but completed baseline and retention balance measurements. An inertial measurement unit was attached to the center of the balance board to assess the performance and learning of the balance task. Resting-state brain connectivity analyses were performed on the fMRI data to contrast connectivity differences for each group at retention relative to baseline, and, for the diffusion data (DTI), fractional anisotropy analyses (a metric to quantify water diffusion within a voxel of white-matter) was performed to quantify the relationship between changes in balance and water diffusivity within white-matter tracts. Classical attentional focus effects were observed for acquisition, with those in the external focus condition producing significantly less mean and standard deviation velocity compared to the internal focus group (both p .05). These results suggest that a seven-day balance training program with attentional focus in a young healthy population influences brain function (specifically correlated activity at rest), but longer training programs or more rest may be needed to influence brain structure (as measured by fractional anisotropy). These findings have important implications for a variety of clinical populations who show altered resting-sate connectivity and deteriorations in balance control (e.g., Alzheimer’s disease, stroke survivors). Seven days of balance training with an external focus may be useful in improving balance control and may influence correlated brain activity at rest, but longer training programs or more rest may be needed to influence brain structure. We discuss these findings in the context of the constrained-action hypothesis and OPTIMAL theory

Embodied geosensification-models, taxonomies and applications for engaging the body in immersive analytics of geospatial data

This thesis examines how we can use immersive multisensory displays and body-focused interaction technologies to analyze geospatial data. It merges relevant aspects from an array of interdisciplinary research areas, from cartography to the cognitive sciences, to form three taxonomies that describe the senses, data representations, and interactions made possible by these technologies. These taxonomies are then integrated into an overarching design model for such "Embodied Geosensifications". This model provides guidance for system specification and is validated with practical examples

Body patterning and cognition in cephalopods - a literature review

Cephalopods are a valuable model for studying the evolution of cognition due to their distinctive brain structure, organisation, and connectivity patterns compared to vertebrates. The development of large brains and behavioural complexities are believed to be triggered by evolutionary pressures stemming from factors like heightened predation, more demanding foraging conditions, and intense mating competition. While the differences between corvid and mammals are less pronounced, the cephalopod brain is closer to the vertebrate brain in terms of encephalisation of ganglionic masses observed by nerve cell clusters. The cerebral ganglion in cephalopods is similar to the vertebrate forebrain and midbrain, while the vertical lobe is similar to the vertebrate cerebral cortex and hippocampus formation, which are involved in learning and memory. These brain regions function in a hierarchical system and are intimately connected with their eyes and optic lobes where visual inputs are processed, motor commands are transmitted to the lower motor centre. Chromatophores are skin elements and the physiological control of body patterning and are visually driven and light sensitive. This sets cephalopods apart from their molluscan families such as gastropods and bivalves. Recent studies have revealed that the opsins present in the skin are like those occurring in the retina. This infers that the connection between visual processing and body patterns is not exclusively innate. Expanding on Macphail's Null Hypothesis which posits no significant qualitative or quantitative differences in intelligence across vertebrates, this study seeks to explore the link between body patterning and cognitive abilities across cephalopod species. By comparing patterns of similarities and differences in cognitive abilities, this study aims to investigate whether body patterning can serve as an indicator of cognitive capacity. In conclusion, the study finds the presence of interindividual variations within species and disparities across different species in both body patterning and cognitive abilities. There are associations between cognitive capacity and body patterns. However, establishing a direct and conclusive connection between high-level cognitive abilities and the expression of body patterns remains elusive, as concrete evidence supporting such a relationship is lacking.Cephalopoda utgör en värdefull modell för att studera den kognitiva evolutionen på grund av deras distinkta hjärnstruktur, organisation och nervernas kontaktmönster jämfört med ryggradsdjur. Utvecklingen av stora hjärnor och komplexa beteenden tros vara resultatet av evolutionär press från faktorer som ökad predation, mer krävande födosökningsförhållanden och intensiv parningskonkurrens. Medan skillnaderna mellan kråkfåglar och däggdjur är mindre uttalade, är bläckfiskhjärnan närmare ryggradsdjurshjärnan när det gäller encefalisering av nervcellkluster. Det cerebrala ganglie hos bläckfiskar liknar ryggradsdjurens främre hjärna och mellanhjärna, medan den vertikala loben liknar ryggradsdjurens hjärnbark och hippocampusformation, som är involverade i inlärning och minne. Dessa hjärnregioner fungerar inom ett hierarkiskt system och är intimt kopplade till deras ögon och optiska lober där visuell information bearbetas och motoriska kommandon överförs till de nedre motoriska centrarna. Kromatoforer är hudstrukturer som fysiologiskt kontrollerar kroppsmönster och är visuellt styrda och ljuskänsliga. Detta skiljer cephalopoder från andra molluskfamiljer som gastropoder och musslor. Studier har nyligenavslöjat att de opsin som finns i huden liknar de som förekommer i näthinnan. Detta antyder att sambandet mellan visuell bearbetning och kroppsmönster inte är uteslutande medfödd. Utöver Macphails nollhypotes, som hävdar att det inte finns några signifikanta kvalitativa eller kvantitativa skillnader i intelligens mellan ryggradsdjur, ämnar denna studie utforska kopplingen mellan kroppsmönster och kognitiva förmågor hos cephalopoda. Genom att jämföra likheter och skillnader i kognitiva förmågor syftar denna studie till att undersöka om kroppsmönster kan fungera som en indikator på kognitiv kapacitet. Resultaten visar på förekomst av variationer mellan individer inom arter och skillnader mellan olika arter både vad gäller kroppsmönster och kognitiva förmågor. Det finns samband mellan kognitiv kapacitet och funktioner samt kroppsmönster. Dock är det fortfarande svårt att fastställa en direkt och definitiv koppling mellan hög kognitiva förmågor och uttrycket av kroppsmönster, eftersom konkret bevis som stöder ett sådant samband saknas