Limb Assignment Task B006cd

Skin location of touch is said to be recoded, by default,
into a 3D-spatial location. Here, human participants
received tactile stimulus pairs on a common or on two
different limbs and judged either whether stimuli had
occurred on the same limb, or on a common side of space.
Misaligning skin and 3D-spatial codes through limb
crossing had a stronger effect on spatial than on limb
judgments, contradicting the notion that the 3D location
of touch is readily available. Additionally, crossing
effects were significantly reduced when stimulus pairs lay
in a common dermatome, suggesting that limb choice was
based on anatomical, not 3D-spatial, stimulus information.
These results suggest that it is limbs, not touch, which
are coded in 3D space. Commonly observed errors in
reporting where touch occurred on the body depend on
confusion due to where the touched limb usually resides
with the spatial layout of the currently action-relevant
limbs.