SPATIAL MEMORY OF BODY LINEAR DISPLACEMENT - WHAT IS BEING STORED

The ability to evaluate traveled distance is common to most animal spe cies. Head trajectory in space is measured on the basis of the converg ing signals of the visual, vestibular, and somatosensory systems, toge ther with efferent copies of motor commands. Recent evidence from huma n studies has shown that head trajectory in space can be stored in spa tial memory. A fundamental question, however, remains unanswered: How is movement stored? In this study, humans who were asked to reproduce passive linear whole-body displacement distances while blindfolded wer e also able to reproduce velocity profiles. This finding suggests that a spatiotemporal dynamic pattern of motion is stored and can be retri eved with the use of vestibular and somesthetic cues.