Does Action Make the Link Between Number and Space Representation?

Abstract

If the visual world is artificially shifted by only 10 degrees, people initially experience difficulty in directing their actions toward visual goals, but then rapidly compensate the visual distortion. The consequence of such adaptation can be measured as visual and proprioceptive aftereffects, as well as by performance on pointing tasks without visual feedback. Recent work has shown that more cognitive deficits can be improved following prism adaptation in patients with unilateral neglect. Here we show that a short visuo-manual adaptation to prisms improves performance on a mental number-bisection task recently shown to be impaired in unilateral neglect. The association previously found between space and number representation (the mental number line) may thus be grounded in common action principles. Our results suggest that visuo-motor plasticity functionally links parietal areas involved in space and number representation.

Visualizing numbers in the mind's eye: The role of visuo-spatial processes in numerical abilities

“…Some studies Zorzi et al, 2002) have argued that, when assessed by this task, the performance of brain-damaged patients with left neglect parallels the rightward error found in the bisection of physical lines (Heilman and Valenstein, 1979;Schenkenberg et al, 1980), by showing a displacement of the numerical centre towards the right side, namely the larger number. Double dissociations between the bisection of physical lines vs. numerical imagined lines are also on record, however, with patients being selectively impaired only in one of these tasks (Doricchi et al, 2005;Rossetti et al, 2004). These findings extend to the spatial representations of numbers the distinction between left neglect for objects in extra-personal space vs. in internally generated visuo-spatial mental images (Anderson, 1993;Bisiach and Luzzatti, 1978;Guariglia et al, 1993).…”

Beyond the SNARC effect: distance–number mapping occurs in the peripersonal space

“…The common representation hypothesis is also supported by studies of brain damaged patients with left neglect syndrome. When the patients were required to point out the midpoint of a number line and a physical line, the same rightward error was evident, indicating that number representation has a spatial nature (Rossetti et al 2004;Zorzi et al 2002).…”

A perception theory in mind–body medicine: guided imagery and mindful meditation as cross-modal adaptation

“…Prism adaptation is the paradigmatic example of cross-modal adaptation (Chapman et al, 2010;Held, 1965;Helmholtz, 1866Helmholtz, /2005Rossetti et al, 2004;Welch, 1978). An observer looks at her own hand through a wedge prism with the thin end to the left.…”