The geometry of eye rotations necessitates an internal reference frame transformation between retinocentric visual codes and headcentric displacement commands for saccades. Here, we ask if this eye position-dependent transformation is bypassed inexpress saccadesa or degraded inmemory saccadesa, perhaps to favor a more direct visuomotor transformation. The answer to both was no: quanti"cation of the behavioral data against simulated predictions revealed a correct biological transformation common to all saccades. This is discussed in terms of ourconversion-on-demanda model, wherein target representations are stored and updated within an early visual frame, but then transformed into appropriate motor frames for ac- tion. 2001 Elsevier Science B.V. All rights reserved.
['Denise Y. P. Henriques', 'J. Douglas Crawford']
Testing the three-dimensional reference frame transformation for express and memory-guided saccades