These classes of
sensors monitor any mismatch between the intended
and actual positions. A so-called ‘postural body scheme’
provides an internal representation of the body geometry,
the body dynamics (support conditions) and the body orientation with respect to verticality. The postural
reactions, like the ‘anticipatory’ postural adjustments
associated with voluntary movements, are organized on
the basis of this internal representation, as is the whole set
of interactions involved in perception and action towards
the external world.