Head, eye and arm coordination in table tennis

The aim of this study was to determine the role of head, eye and arm movements during the execution of a table tennis forehand stroke. Three-dimensional kinematic analysis of line-of-gaze, arm and ball was used to describe visual and motor behaviour. Skilled and less skilled participants returned the ball to cued right or left target areas under three levels of temporal constraint: pre-, early- and late-cue conditions. In the pre- and early-cue conditions, both high and low skill participants tracked the ball early in flight and kept gaze stable on a location in advance of the ball before ball-bat contact. Skilled participants demonstrated an earlier onset of ball tracking and recorded higher performance accuracy than less skilled counterparts. The manipulation of cue condition showed the limits of adaptation to maintain accuracy on the target. Participants were able to accommodate the constraints imposed by the early-cue condition by using a shorter quiet eye duration, earlier quiet eye offset and reduced arm velocity at contact. In the late-cue condition, modifications to gaze, head and arm movements were not sufficient to preserve accuracy. The findings highlight the functional coupling between perception and action during time-constrained, goal-directed actions.

Evaluation of Pupillary Diameter in Preschool Children

Few quantitative data exist on pupil diameter, particularly in children. In this article we describe an analysis of pupil diameter and pupil area in normal preschool children during attentive gaze (AG) and spontaneous gaze (SG) using digital imaging. The pupil diameter and pupil area of 200 preschool children aged 4 to 6 years were evaluated. The images were recorded with a digital camera, transferred to a computer, processed by movie software and submitted to the Invert filter of Adobe Photoshop (R) software. Three consecutive measures of pupil diameter and pupil area were taken for both eyes during AG and SG. Arithmetic means of each parameter were calculated and data were expressed in millimeters. Mean pupil diameter was similar for both eyes, presenting values of 4.9 mm during AG and 4.1 mm during SG. Mean pupil area was also similar for both eyes, presenting values of 15.6 mm(2) and 9.1 mm(2) during AG and SG, respectively. There were no differences between boys and girls. However, 6-year-old children showed lower pupil diameter and area under both evaluation conditions.

Effects of saccadic eye movements on postural control in older adults

Saccadic eye movements have been shown to affect posture by decreasing the magnitude of body sway in young adults. However, there is no evidence of how the search for visual information that occurs during eye movements affects postural control in older adults. The purpose of the present study was to determine the influence of saccadic eye movements on postural control in older adults while they stood on 2 different bases of support. Twelve older adults stood upright in 70-s trials under 2 stance conditions (wide and narrow) and 3 gaze conditions (fixation, saccadic eye movements at 0.5 Hz, and saccadic eye movements at 1.1 Hz). Head and trunk sway amplitude and mean sway frequency were measured in both the anterior/posterior (AP) and medial/lateral (ML) directions. The results showed that the amplitude of body sway was reduced during saccades compared with fixation, as previously observed in young adults. However, older adults exhibited similar sway amplitude and frequency in the AP direction under the wide and narrow stance conditions, which is different from observations in young adults, who display larger sway in a narrow stance compared with a wide stance while performing saccades. These results suggest that although older adults are affected by saccadic eye movements by a decrease in the amplitude of body sway, as observed in young adults, they present a more rigid postural control strategy that does not allow larger sway during a more challenging stance condition.

Efeito distrator do telefone celular sobre a condução simulada de automóveis: situações de uso manual e viva-voz

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Um estudo da arte-sequencial: os componentes imagéticos e textuais em homem-aranha : azul

Comic books, graphic narrative and sequential art, had their origin in newspapers, in the period of the Industrial Revolution. First published weekly in the comic strip format, with the passage of time, the new form of literature has gained more and more public and comic strips became complete stories in the format of comic books and later, graphic novels. This course's final paper aims to present the main components of comics: the picture and the text; and to examine the way in which these two elements overlap and complement each other in the configuration of comics as a whole. As the object of analysis, it was chosen the graphic novel Spider-Man: Blue, first published in 2002 as part of a project composed by three other titles from the double winning cartoonists of the Eisner Award, Jeph Loeb and Tim Sale. For theoretical background, was chosen the book Os Quadrinhos - Linguagem e Semiótica: Um Estudo Abrangente da Arte Sequencial written by the researcher Antonio Luiz Cagnin, which presents a study of all components found in the sequential art and treated in this work: the narrative time, visual plans, balloons, caption, and onomatopoeia

Gaze pursuit and arm control of adolescent males diagnosed with attention deficit hyperactivity disorder (ADHD) and normal controls: evidence of a dissociation in processing visual information of short and long duration

Three-dimensional kinematic analysis of line of gaze, arm and ball was used to describe the visual and motor behaviour of male adolescents diagnosed with attention deficit hyperactivity disorder (ADHD). The ADHD participants were tested when both on (ADHD-On) and off (ADHD-Off) their medication and compared to age-matched normal controls in a modified table tennis task that required tracking the ball and hitting to cued right and left targets. Long-duration information was provided by a pre-cue, in which the target was illuminated approximately 2 s before the serve, and short-duration information by an early-cue illuminated about 350 ms after the serve, leaving -500 ms to select the target and perform the action. The ADHD groups differed significantly from the control group in both the pre-cue and early-cue conditions in being less accurate, in having a later onset and duration of pursuit tracking, and a higher frequency of gaze on and off the ball. The use of medication significantly reduced the gaze frequency of the ADHD participants, but surprisingly this did not lead to an increase in pursuit tracking, suggesting a barrier was reached beyond which ball flight information could not be processed. The control and ADHD groups did not differ in arm movement onset, duration and velocity in the short-duration early-cue condition; in the long-duration pre-cue condition, however, the ADHD group's movement time onset and arm velocity differed significantly from controls. The results show that the ADHD groups were able to process short-duration information without experiencing adverse effects on their motor behaviour; however, long-duration information contributed to irregular movement control.