Examining the equivalence between imagery and execution - Do imagined and executed movements code relative environmental features?

Imagined actions engage some of the same neural substrates and related sensorimotor codes as executed actions. The equivalency between imagined and executed actions has been frequently demonstrated by the mental and physical chronometry of movements; namely, the imagination and execution of aiming movements in a Fitts paradigm. The present study aimed to examine the nature or extent of this equivalence, and more specifically, whether imagined movements encompass the relative environmental features as do executed movements. In two separate studies, participants completed a series of imagined or executed reciprocal aiming movements between standard control targets (no annuli), perceptually small targets (large annuli) and perceptually large targets (small annuli) (Ebbinghaus illusions). The findings of both studies replicated the standard positive relation between movement time and index of difficulty for imagined and executed movements. Furthermore, movement times were longer for targets with surrounding annuli compared to the movement times without the annuli suggesting a general interference effect. Hence, the surrounding annuli caused a longer time, independent of the illusory target size, most likely to avoid a potential collision and more precisely locate the endpoint. Most importantly, this feature could not be discriminated as a function of the task (imagined vs. executed). These findings lend support to the view of a common domain for imagined and executed actions, while elaborating on the precision of their equivalence

The effect of modeled absolute timing variability and relative timing variability on observational learning.

There is much evidence to suggest that skill learning is enhanced by skill observation. Recent research on this phenomenon indicates a benefit of observing variable/erred demonstrations. In this study, we explore whether it is variability within the relative organization or absolute parameterization of a movement that facilitates skill learning through observation. To do so, participants were randomly allocated into groups that observed a model with no variability, absolute timing variability, relative timing variability, or variability in both absolute and relative timing. All participants performed a four-segment movement pattern with specific absolute and relative timing goals prior to and following the observational intervention, as well as in a 24h retention test and transfers tests that featured new relative and absolute timing goals. Absolute timing error indicated that all groups initially acquired the absolute timing, maintained their performance at 24h retention, and exhibited performance deterioration in both transfer tests. Relative timing error revealed that the observation of no variability and relative timing variability produced greater performance at the post-test, 24h retention and relative timing transfer tests, but for the no variability group, deteriorated at absolute timing transfer test. The results suggest that the learning of absolute timing following observation unfolds irrespective of model variability. However, the learning of relative timing benefits from holding the absolute features constant, while the observation of no variability partially fails in transfer. We suggest learning by observing no variability and variable/erred models unfolds via similar neural mechanisms, although the latter benefits from the additional coding of information pertaining to movements that require a correction

Impression or expression? The influence of self-monitoring on the social modulation of motor contagion

Social primes (pro-social, anti-social) can modulate mimicry behaviour. To date, these social modulation effects have been explained by the primed incentive to affiliate with another (Social Top-Down Response Modulation; STORM) and the primed active-self-concept leading to behaviour that is either consistent or inconsistent with the prime-construct (Active-Self account). The present study was designed to explore the explanatory power for each of these accounts, and thereby gain a greater understanding of how social modulation unfolds. To do this, we assessed social modulation of motor contagion in individuals high or low in self-monitoring. It was reasoned that high self-monitors would modulate mimicry according to the primed social incentive, whereas low self-monitors would modulate according to the primed active-self-concept. Participants were primed with a pro-social and anti-social cue in the first-person and third-person perspective. Next, they completed an interpersonal observation-execution task featuring the simultaneous observation and execution of arm movements that were either congruent or incongruent to each other. Results showed increased incongruent movement deviation (motor contagion) for the anti-social compared to the pro-social prime in the high self-monitors only. Findings support the STORM account of mimicry by showing observers modulate behaviour based on the social incentive underpinning an interpersonal exchange

Top-Down Attentional Processes Modulate the Coding of Atypical Biological Motion Kinematics in the Absence of Motor Signals

The acquisition of sensorimotor parameters that control goal-directed motor behaviors occurs by observing another person in the absence of efferent and afferent motor signals. This is observational practice. During such observation, biological motion properties associated with the observed person are coded into a representation that controls motor learning. Understanding the underlying processes, specifically associated with coding biological motion, has theoretical and practical significance. Here, we examined the following questions. Experiment 1: Are the underlying velocity characteristics associated with observed biological motion kinematics imitated? Experiment 2: Is attention involved in imitating biological motion kinematics? Experiment 3: Can selective attention modulate how biological motion kinematics are imitated/represented? To this end, participants practiced by observing a model performing a movement sequence that contained typical or atypical biological motion kinematics. The differences in kinematics were designed to dissociate the movement constraints of the task and the anatomical constraints of the observer. This way, we examined whether novel motor behaviors are acquired by adopting prototypical movements or coding biological motion. The kinematic analyses indicated the timing and spatial position of peak velocity were represented. Using a dual-task protocol, we attenuated the coding of biological motion kinematics (Experiment 2) and augmented coding using a selective attention protocol (Experiment 3). Findings indicated that velocity characteristics of biological motion kinematics are coded during observational practice, most likely through bottom-up sensorimotor processes. By modulating motion coding using 2 attentional protocols, we showed that bottom-up processes are influenced by input modulation, which is consistent with top-down control during observational practice

Top-down and bottom-up processes during observation: Implications for motor learning

Neurophysiological and behavioural research has linked observational practice to a 2 mirroring mechanism encompassing the action-observation network (AON). Although the 3 original findings indicate that biological stimuli alone activate the AON, recent evidence 4 has shown sensitivity to non-biological stimuli. Thus, the AON is suggested to be 5 influenced by interacting bottom-up and top-down processes. In this review, we describe 6 the multi-functional properties of the AON, and discuss the implications for observational 7 practice and subsequent motor learning

Inkjet printed multimetal microelectrodes on PDMS for functionalized microfluidic systems

A novel direct method of metal microelectrode patterning on polydimethylsiloxane (PDMS) using inkjet printed gold and silver nanoparticles to form electrochemical sensors is presented. Inkjet printing is an additive microfabrication technique enabling microelectrode patterning directly over large areas at low-temperatures. (3-mercaptopropyl) trimethoxysilane (MPTMS) to promote PDMS surface wettability and improve metal adhesion and a pixel-printing subsampling method to overcome surface tension driven ink-droplet coalescence, are then employed to form a robust fabrication process. The resulting printed gold and silver microelectrodes exhibit good compactness, continuity and conductivity, and are used to manufacture functionalized microfluidic systems with in-situ three-electrode electrochemical sensors.published_or_final_versio

Aalto’s landscape ontology : conceptualising landscape in Alvar Aalto’s architecture using phenomenological concepts of place, atmosphere and embodiment

This thesis investigates the work of the twentieth-century Finnish modernist architect Alvar Aalto (1898-1976), as involved and intertwined with ideas and experiences of landscape. Late in his life, Aalto said that from his earliest years the Finnish landscape ‘was there all around me, all the time.’ Aalto has been regarded historically as the modernist misfit, a Northern humanist outlier working at the margins of rational modern architecture. Aalto’s architecture arguably extends, expands and evolves modernism to embrace a body-based humanism, informed by a socio-ethical agenda supporting the everyday ‘little man’, confronted by twentieth-century modernity. Aalto’s alternative or heterodox architecture is argued in this study as based in the historically acknowledged, yet largely unexplored, involvement of his work with landscape, evident in the conceptualisation, siting, design, details, and the experience of his work. This thesis investigates the significance of landscape in Aalto’s work by conceptualising his architecture in terms of its relationship to landscape, addressing the lack of a sustained study of the significance of landscape in Aalto’s work. This historical-theoretical study investigates Aalto’s architecture, in buildings, details and elements, drawings, unbuilt projects, and architectural images, from the 1920s to the 1970s. Through these selected historical examples, the involvement of landscape in Aalto’s work emerges as an essential difference, distinguishing his heterodox practice from the orthodoxy of twentieth-century modern architecture. The study innovatively organises Aalto’s work into three landscape-related historical themes, of White, Waves and Ruins. While landscape offered a topic for investigating landscape in Aalto’s work in this author’s MPhil(Arch) research into prospect-refuge symbolism (2010), these three themes emerged as relevant to investigating landscape through research articles published or presented by this author between 2010-2018. This study makes its particular contribution to architectural scholarship through a series of close readings of Aalto’s work, interpreting landscape in his architecture with reference to key phenomenological concepts of Place, Atmosphere and Embodiment. The study investigates renowned Aalto works such as Villa Mairea, Muuratsalo House and Aalto Atelier, along with lesser-known works such as Summa House, Alajärvi Town Hall and Seinäjoki Theatre, as well as sketches, images and details of Aalto works. The thesis describes, analyses and interprets the significance of both Aalto’s architecture in the landscape, and landscape elements in his architecture, with reference to Aalto’s ‘own words’, to the wider Aalto literature, and to interdisciplinary literature on the phenomenology of Place, Atmosphere and Embodiment. Aalto’s lifelong familiarity with the Finnish landscape and his experience of its topography, geology, vegetation, water, weather mythology gave him a unique capacity to involve his work with landscape. Aalto’s familiarity with landscape was further informed by his interests in biology, art, history and literature, and was driven in part by his empathy for the ‘little man’, the everyday person struggling with the conflicts and changes of the twentieth century. The analysis of the study refers to the thinking of Norberg-Schulz and Pallasmaa on architectural phenomenology. It builds also on Wylie’s geographical theorisation of the phenomenology of landscape, and is based indirectly on the phenomenological philosophies of Merleau-Ponty and of Heidegger, through architectural readings of their work. The study uses recent theoretical and historical work – including Malpas on place, Böhme on atmosphere, and Goldhagen on embodiment – to locate Aalto’s work within recent and contemporary thinking on phenomenology in landscape and architecture. Landscape is argued through the thesis as giving an ontological basis to Aalto’s method. Landscape emerges as forming a fundamental, originary architectural beginning, without which Aalto could not have imagined and created his architecture, without which experience of his work could not be fully described or investigated, and without which contemporary understanding of his work would remain less comprehensive. As such, landscape, categorised into historical themes of White, Waves and Ruins and read through phenomenological concepts of Place, Atmosphere and Embodiment, offers a unique resource for investigating the meaning and significance of Aalto’s architecture. As an investigation of landscape through its close reading of Aalto’s work, the present study aims to expand understanding of Aalto’s complex and enduring modern architecture, and of the broader significances of landscape for contemporary architectural thinking and practice

The Impact of Strategic Trajectory Optimization on Illusory Target Biases During Goal-Directed Aiming

During rapid aiming, movements are planned and executed to avoid worst-case outcomes that require time and energy to correct. As such, downward movements initially undershoot the target to avoid corrections against gravity. Illusory target context can also impact aiming bias. Here, the authors sought to determine how strategic biases mediate illusory biases. Participants aimed to Müller-Lyer figures in different directions (forward, backward, up, down). Downward biases emerged late in the movement and illusory biases emerged from peak velocity. The illusory effects were greater for downward movements at terminal endpoint. These results indicate that strategic biases interact with the limb-target control processes associated with illusory biases. Thus, multiple control processes during rapid aiming may combine and later affect endpoint accuracy (D. Elliott et al., 2010)

Gunslinger Effect and Muller-Lyer Illusion: Examining Early Visual Information Processing for Late Limb-Target Control

The multiple process model contends that there are two forms of online control for manual aiming: impulse regulation and limb-target control. This study examined the impact of visual information processing for limb-target control. We amalgamated the Gunslinger protocol (i.e., faster movements following a reaction to an external trigger compared with the spontaneous initiation of movement) and Müller-Lyer target configurations into the same aiming protocol. The results showed the Gunslinger effect was isolated at the early portions of the movement (peak acceleration and peak velocity). Reacted aims reached a longer displacement at peak deceleration, but no differences for movement termination. The target configurations manifested terminal biases consistent with the illusion. We suggest the visual information processing demands imposed by reacted aims can be adapted by integrating early feedforward information for limb-target control