Coordinates of Extracorporeal Space

Bradshaw, John L.; Nettleton, Norman C.; Pierson, Jane; Wilson, Lyn; Nathan, Gregory

doi:10.1016/s0166-4115(08)61708-2

Cited by 42 publications

(32 citation statements)

References 85 publications

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“…Evidence of an additional proximal bias is based on the observation that parietal (area 7b) "neglect" in monkeys is biased toward peripersonal space, whereas damage to the arcuate region of prefrontal cortex (containing the frontal eye fields) leads to a greater neglect of extrapersonal space (Rizzolatti et al 1985). This coincides with evidence in humans that parietal neglect -along with many other visual lateralization phenomena -appears to be framed more in terms of body-centered rather than retinotopic coordinates (Bradshaw, Nettleton et al 1987;Gazzaniga & Ladavas 1987;Kooistra & Heilman 1989).…”

Section: Wisual Attentionsupporting

confidence: 87%

Functional specialization in the lower and upper visual fields in humans: Its ecological origins and neurophysiological implications

Previc¹

1990

Behav Brain Sci

609

516

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Functional specialization in the lower and upper visual fields in humans is analyzed in relation to the origins of the primate visual system. Processing differences between the vertical hemifields are related to the distinction between near (peripersonal) and far (extrapersonal) space, which are biased toward the lower and upper visual fields, respectively. Nonlinear/global processing is required in the lower visual field in order to pergeive the optically degraded and diplopic images in near vision, whereas objects in far vision are searched for and recognized primarily using linear/local perceptual mechanisms. The functional differences between near and far visual space are correlated with their disproportionate representations in the dorsal and ventral divisions of visual association cortex, respectively, and in the magnocellular and parvocellular pathways that project to them. Advances in far visual capabilities and forelimb manipulatory skills may have led to a significant enhancement of these functional specializations.

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Section: Wisual Attentionsupporting

confidence: 87%

Functional specialization in the lower and upper visual fields in humans: Its ecological origins and neurophysiological implications

Previc¹

1990

Behav Brain Sci

609

516

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“…In the horizontal plane while sitting upright, moderate, nonsignificant leftward shifts relative to objective midline have repeatedly been described for both line bisecting (Brodie and Dunn 2005;Chokron et al 2002) and pointing straight-ahead tasks (for a review, see Jewell and McCourt 2000), termed "pseudo-neglect" (Bowers and Heilman 1980). Leftward deviations of the subjective midline have been linked to the spatial nature of the task, which may preferentially activate the right hemisphere (Heilman et al 1987;Kinsbourne 1970Kinsbourne , 1973Reuter-Lorenz et al 1990) with resultant enhancement of the left perceptual field (Bradshaw et al 1987;Scarisbrick et al 1987). The analogy in offsets in the frontal plane compared with those reported in the horizontal plane raises the question whether "pseudo-neglect" might contribute to shifts in both planes.…”

Section: Systematic Shifts In Haptic Alignments and Dependence On Thementioning

confidence: 99%

Egocentric and allocentric alignment tasks are affected by otolith input

Tarnutzer

Bockisch

Olasagasti

et al. 2012

Journal of Neurophysiology

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Gravicentric visual alignments become less precise when the head is roll-tilted relative to gravity, which is most likely due to decreasing otolith sensitivity. To align a luminous line with the perceived gravity vector (gravicentric task) or the perceived body-longitudinal axis (egocentric task), the roll orientation of the line on the retina and the torsional position of the eyes relative to the head must be integrated to obtain the line orientation relative to the head. Whether otolith input contributes to egocentric tasks and whether the modulation of variability is restricted to vision-dependent paradigms is unknown. In nine subjects we compared precision and accuracy of gravicentric and egocentric alignments in various roll positions (upright, 45°, and 75° right-ear down) using a luminous line (visual paradigm) in darkness. Trial-to-trial variability doubled for both egocentric and gravicentric alignments when roll-tilted. Two mechanisms might explain the roll-angle-dependent modulation in egocentric tasks: 1) Modulating variability in estimated ocular torsion, which reflects the roll-dependent precision of otolith signals, affects the precision of estimating the line orientation relative to the head; this hypothesis predicts that variability modulation is restricted to vision-dependent alignments. 2) Estimated body-longitudinal reflects the roll-dependent variability of perceived earth-vertical. Gravicentric cues are thereby integrated regardless of the task's reference frame. To test the two hypotheses the visual paradigm was repeated using a rod instead (haptic paradigm). As with the visual paradigm, precision significantly decreased with increasing head roll for both tasks. These findings propose that the CNS integrates input coded in a gravicentric frame to solve egocentric tasks. In analogy to gravicentric tasks, where trial-to-trial variability is mainly influenced by the properties of the otolith afferents, egocentric tasks may also integrate otolith input. Such a shared mechanism for both paradigms and frames of reference is supported by the significantly correlated trial-to-trial variabilities.

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“…In essence, this is the definition of limb dominance. However, in recent years this notion has been questioned in light of evidence that hand preference may be modified by attentional stimuli (Bradshaw, , 1987;Hellige & Kee, 1990;Peters, 1995;Verfaellie & Heilman, 1990). To illustrate, in a recent series of experiments involving choice of hand for a visual and auditory (while blindfolded) reach-tograsp task across a range of right-, mid-, and left-hemispace positions (Figure l), we observed evidence supporting attentional effects; a part of these findings has been reported (Gabbard, Iteya, & Rabb, 1997).…”

mentioning

confidence: 99%

What Determines Choice of Limb for Unimanual Reaching Movements?

Gabbard

Rabb

2000

The Journal of General Psychology

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Currently, relatively little is known about what drives the choice of limb for goal-oriented reaching. Traditionally, the explanation has been tied predominately to motor dominance as manifested in handedness. This article offers data and an argument suggesting that handedness can be modified by attentional (spatial) information. Although motor dominance may be the controlling factor in the programming and execution of reaching movements at the midline and hemispace ipsilateral (same side) to the dominant limb, attentional information alters the programming of movements in what would be contralateral space. The general trend of behavior is characterized by reaching on the same side as the stimulus, in ipsilateral fashion, a phenomenon explained by kinesthetic efficiency and hemispheric bias.

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Coordinates of Extracorporeal Space

Cited by 42 publications

References 85 publications

Functional specialization in the lower and upper visual fields in humans: Its ecological origins and neurophysiological implications

Functional specialization in the lower and upper visual fields in humans: Its ecological origins and neurophysiological implications

Egocentric and allocentric alignment tasks are affected by otolith input

What Determines Choice of Limb for Unimanual Reaching Movements?

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