The myth of upright vision. A psychophysical and functional imaging study of adaptation to inverting spectacles.

The adaptation to inverting prisms and mirror spectacles was studied in four subjects over periods of six to ten days. Subjects showed rapid adaptation of visuomotor functions, but did not report return of upright vision. The persistence of the transformed visual image was confirmed by the subjects' perception of shape from shading. No alteration of the retinotopy of early visual cortical areas was seen in the functional magnetic resonance images. These results are discussed in the context of previous claims of upright vision with inverting prisms and mirror spectacles.