Biomedical subjects

José A Barela

Publications and source records attributed to José A Barela.

4 recordsLinked to original sources

PubMed2005

Visual timing and adaptive behavior in a road-crossing simulation study.

In this road-crossing simulation study, we assessed both participant's ability to visually judge whether or not they could cross a road, and their adaptive walking behavior. To this end, participants were presented with a road inside the laboratory on which a bike approached with different velocities from different distances. Eight children aged 5-7, ten children aged 10-12, and ten adults were asked both to verbally judge whether they could cross the road, and to actually walk across the road if possible. The results indicated that the verbal judgments were not similar to judgments to actually cross the road. With respect to safety and accuracy of judgments, groups did not differ from each other, although the youngest group tended to be more cautious. All groups appeared to use a strategy to cross the road based both on the distance and the velocity of the approaching bike. Young children waited longer on the curb before crossing the road than older children and adults. All groups adjusted their crossing time to the time-to-arrival of the bike. These findings are discussed in relation to the ecological psychological approach and the putative dissociation between vision for perception (i.e. verbal judgment) and vision for action (i.e. actual crossing).

Accidents, Traffic↗

PubMed2004

Postural control as a function of self- and object-motion perception.

The goals of this study were to examine the visual information influence on body sway as a function of self- and object-motion perception and visual information quality. Participants that were aware (object-motion) and unaware (self-motion) of the movement of a moving room were asked to stand upright at five different distances from its frontal wall. The visual information effect on body sway decreased when participants were aware about the sensory manipulation. Moreover, while the visual influence on body sway decreased as the distance increased in the self-motion perception, no effects were observed in the object-motion mode. The overall results indicate that postural control system functioning can be altered by prior knowledge, and adaptation due to changes in sensory quality seem to occur in the self- but not in the object-motion perception mode.

Adult↗

PubMed2003

Postural control in children. Coupling to dynamic somatosensory information.

The purpose of this investigation was to determine whether the coupling between dynamic somatosensory information and body sway is similar in children and adults. Thirty children (4-, 6-, and 8-year-olds) and 10 adults stood upright, with feet parallel, and lightly contacting the fingertip to a rigid metal plate that moved rhythmically at 0.2, 0.5, and 0.8 Hz. Light touch to the moving contact surface induced postural sway in all participants. The somatosensory stimulus produced a broadband frequency response in children, while the adult response was primarily at the driving frequency. Gain, as a function of frequency, was qualitatively the same in children and adults. Phase decreased less in 4-year-olds than other age groups, suggesting a weaker coupling to position information in the sensory stimulus. Postural sway variability was larger in children than adults. These findings suggest that, even as young as age 6, children show well-developed coupling to the sensory stimulus. However, unlike adults, this coupling is not well focused at the frequency specified by the somatosensory signal. Children may be unable to uncouple from sensory information that is less relevant to the task, resulting in a broadband response in their frequency spectrum. Moreover, higher sway variability may not result from the sensory feedback process, but rather from the children's underdeveloped ability to estimate an internal model of body orientation.

Adult↗

PubMed2003

Proprioceptive and behavior impairments in individuals with anterior cruciate ligament reconstructed knees.

OBJECTIVE: To assess sensory deficits and their effects on proprioceptive and motor function in patients who had undergone unilateral anterior cruciate ligament (ACL) reconstruction. DESIGN: Four evaluations were conducted: (1) joint position perception of the knee for predetermined angles (0 degrees, 15 degrees, 30 degrees, 45 degrees, 60 degrees ); (2) threshold for detection of passive knee motion at 0 degrees, 15 degrees, 30 degrees, 45 degrees, and 60 degrees moving into flexion and at 15 degrees, 30 degrees, 45 degrees, and 60 degrees moving into extension; (3) latency onset of hamstring muscles; and (4) postural control during upright double- and single-leg stance. SETTING: Movement laboratory in Brazil. PARTICIPANTS: Ten participants who had surgical reconstruction of the ACL (reconstructed group) and 10 participants without knee injury (control group). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Absolute error, angular displacement, hamstring muscles latency, and mean sway amplitude. RESULTS: Individuals with a reconstructed knee showed decreased joint position perception, a higher threshold for detection of passive knee motion, longer latency of hamstring muscles, and decreased performance in postural control. CONCLUSIONS: After lesion and ACL reconstruction, sensory and motor behavior changes were still observed. This may be because of the lack of proprioceptive information resulting from the ACL lesion and/or substitution of ACL by the graft.

Adult↗