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Young people's perception of the space shuttle disaster: case study.

To explore how young people were affected by the space shuttle disaster, the responses of 79 females in 5th, 8th, and 12th grades and 18 males in 5th grade who had witnessed the event on video at school were examined. Six days after the Challenger accident, they were asked to list and rank the three things that had affected them most over the last seven days and to explain the reason behind their first choice. Only 8.9% of the females ranked the space shuttle first, and only 30.4% ranked it in the top three. Competing issues were school-related activities, grades, and family relations. Of the 5th-grade males, 88.9% mentioned the space shuttle and 38.9% saw it as their top concern. For both males and females, this choice was based on sadness and empathy. The youths did not relate the disaster to the fragility of modern technology or the threat of nuclear war. The relatively low response rate of the females who had witnessed this event was interpreted as being indicative of repression-denial. It was concluded that future research should address the extent to which post-crisis denial could be masking more significant psychological trauma in youth.

Adolescent↗

[Perception of 2-dimensional space coordinates during prolonged experimental hypokinesia].

The effect of a 30-day hypokinesia on the perception of the subjective optic vertical (SOV) was studied. The test subjects who were in the antiorthostatic position (at an angle of 96 degrees to the vertical) showed the greatest changes in the SOV perception and illusive perception of the spatial position of the body. During the first two days of the experiment and ten days after it they displayed a 1.5-fold increase in the error of the SOV perception. In addition, they exhibited an asymmetrical perception of the SOV on the right and left side. In all cases the direction of the SOV displacement from the true line coincided with the body position. The test subjects who were kept at an angle of 84 degrees to the vertical (orthostatic hypokinesia) demonstrated only illusions of the body position during the first hypokinetic day and a unilateral increase in the error of the SOV perception after the experiment. The test subjects who underwent preventive treatment following antiorthostatic hypokinesia (at an angle of 94 degrees to the vertical) exhibited no asymmetry and an insignificant error in the SOV perception. These findings are discussed with regards to the changes in the function of pressuretension receptors and disorders in the skeletal tone during hypokinesia.

Adult↗

Spatial attention and two modes of visual consciousness.

The relationship between spatial attention and visual consciousness was critically examined in an attempt to show the operation of two simultaneously available modes of visual consciousness (i.e., object consciousness, which concerns the conscious identification of objects, and background consciousness, which deals with conscious monitoring of the background scene). The traditional view seems to pay attention only to object consciousness, which is a product of spatial attention. To substantiate the hypothesis, five topics from varied fields of human experimental psychology were chosen: iconic storage, stabilized retinal image disappearance, stable perception of external space, texture segregation and attention, and spatial frequency sensitivity in a figure-ground reversal figure. The findings of these studies suggest that there may be visual consciousness outside of focal attention and that background consciousness operates as a default mode for global scene analysis and early warning of anomalies. Finally, neural substrata for these two modes of consciousness are suggested.

Attention↗

Evidence from a line bisection task for visuospatial neglect in left hemiparkinson's disease.

The perception of extrapersonal space in Parkinson's disease was examined with two line bisection tasks. One was a conventional pencil and paper test, the line bisection section of the Behavioural Inattention Test. In the other, the stimuli were displayed on a large (2x2.4 m) screen and varied in length (48-480 mm) and also in location on the screen (left, centre and right). They were presented at two viewing distances (0.6 and 1.5 m). Subjects remotely adjusted the position of a cursor until it appeared to bisect the stimulus line, using two push-buttons, one in each hand. The PD participants (n=18) had a marked asymmetry of motor symptoms. They were divided into two groups, those with predominantly left-sided motor symptoms (LPD, n=9), and those with predominantly right-sided motor symptoms (RPD, n=9). The control group (n=9) were all right-handed. No significant differences between the groups were found on the BIT bisection task. In contrast, when the stimuli were presented on the screen, LPD subjects showed a significant rightward bias in their settings of the cursor, particularly for lines on the left and centre of the screen, which was greater, the longer the stimulus line. The RPD group bisected lines slightly to the left, in common with the control group (pseudo-neglect). In a second experiment, Parkinsonian subjects repeated this task, but with the buttons reversed between the hands, so that the cursor was moved to the left by the right hand, and vice versa, but the pattern of results was the same as in the first experiment. The data suggest a small but reliable neglect in left hemiparkinson's disease, which is contralateral to the non-dominant (and probably worse affected) hemisphere. The dissociation between the response and the bisection error suggests a visuospatial impairment in LPD.

Aged↗

Active vision in parietal and extrastriate cortex.

Vision is an active process. We do not see the world directly; rather, we construct a representation of it from sensory inputs in combination with internal, nonvisual signals. In the case of spatial perception, our representation of the visual scene must take into account our own movements. This allows us to perceive the world as stationary despite the constant eye movements that produce new images on the retina. How is this perceptual stability achieved? Our central hypothesis is that a corollary discharge of the eye movement command updates, or remaps, an internal representation when the eyes move. In support of this hypothesis, the authors review evidence that parietal cortex and extrastriate visual areas in both monkeys and humans participate in spatial updating. These findings shed new light on the neural circuitry involved in producing a stable and coherent perception of visual space.

Action Potentials↗