Percepção e ação: direções teóricas e experimentais atuais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Developing an Anchor system to enhance postural control

This article uses an anchor metaphor to explain the dynamic interplay between the human body's active uses of nonrigid tools to mediate information about its adjacent environment to enhance postural control. The author used an anchor system (ropes attached to varying weights resting on the floor) to test blindfolded adults who performed a restricted-balance task (30 s one-foot standing). Participants were tested while holding the anchors under a variety of weight conditions (125 g, 250 g, 500 g, and I kg) and again during a baseline condition (no anchors). When compared with the baseline condition, there was a significant reduction in the amount of body sway across the anchor conditions. The author found that mechanical support provided by the anchor system was secondary to its haptic exploratory function and that an individual can use the anchoring strategy with a dual purpose: for resting and for reorientation after intrinsic disruptions.

What is Consciousness? Towards a Preliminary Definition

There is little or no general agreement about what researchers should focus on when studying consciousness. The most active scientific studies often use the methods of Cognitive Neuroscience and focus mainly on vision. Other aspects and contents of consciousness, namely thoughts and emotions, are much less studied, possibly leading to a biased view of what consciousness is and how it works. In this essay we describe what we call a referential nucleus, implicit in much of consciousness research. In this context, 'consciousness' refers to (partially) reportable content experienced by living individuals. We then discuss the philosophical concept of a phenomenal world and another contemporary view that conscious experience involves, besides integration of information in the brain, participation in action-perception cycles in a natural, social and cultural environment. These views imply a need to reconceptualize 'qualia' as the conscious aspect of subjective experiences, thus stating properties of consciousness that pose serious challenges to an exclusive approach via Cognitive Neuroscience, because experimental settings oversimplify conscious experiences, narrowing them to fragments correlated with measured brain activity and behaviour In conclusion we argue that a science of consciousness requires a broad interdisciplinary range of research, including qualitative methods from the Human Sciences.

Indução ao esforço e seus efeitos em parâmetros da percepção espacial de indivíduos atletas deficientes visuais e não deficientes

Pós-graduação em Ciências da Motricidade - IBRC

O papel das representações mentais na percepção-ação: uma perspectiva crítica

Pós-graduação em Filosofia - FFC

Perception-action and adaptation in postural control of children and adolescents with cerebral palsy

The aim of this study was to examine the coupling between visual information and body sway and the adaptation in this coupling of individuals with cerebral palsy (CP). Fifteen children with and 15 without CP. 6-15 years old, were required to stand upright inside of a moving room. All children first performed two trials with no movement of the room and eyes open or closed, then four trials in which the room oscillated at 0.2 or 0.5 Hz (peak velocity of 0.6 cm/s), one trial in which the room oscillated at 0.2 Hz (peak velocity of 3.5 cm/s), and finally two other trials in which the room oscillated again at 0.2 Hz (peak velocity of 0.6 cm/s). Participants with CP coupled body sway to visual information provided by the moving room, comparable to the coupling of participants without CP. However, participants with CP exhibited larger body sway in maintaining upright position and more variable sway when body sway was induced by visual manipulation. They showed adaptive sensory motor coupling, e.g. down-weighting visual influence when a larger stimulus was provided, but not with the same magnitude as typically developing participants. This indicates that participants with CP have less capability of adaptation. (C) 2011 Published by Elsevier Ltd.

Perception-action coupling in infants with down syndrome: Effects of experience and practice

This study examined the effects of experience and practice on the coupling between visual information and trunk sway in infants with Down syndrome (DS). Five experienced and five novice sitters were exposed to a moving room, which was oscillated at 0.2 and 0.5 Hz. Infants remained in a sitting position and data were collected on the first, fourth, and seventh days. On the first day, experienced sitters were more influenced by room oscillation than were novices. On the following days, however, the influence of room oscillation decreased for experienced but increased for novice sitters. These results suggest that the relationship between sensory information and motor action in infants with DS can be changed with experience and practice.

The calcium wave model of the perception-action cycle: Evidence from semantic relevance in memory experiments

We present a general model of brain function (the calcium wave model), distinguishing three processing modes in the perception-action cycle. The model provides an interpretation of the data from experiments on semantic memory conducted by the authors. © 2013 Pereira Jr, Santos and Barros.