  The thalamus is the major gate to the cortex and its control over cortical
responses is well established. Cortical feedback to the thalamus is, in turn,
the anatomically dominant input to relay cells, yet its influence on thalamic
processing has been difficult to interpret. For an understanding of complex
sensory processing, detailed concepts of the corticothalamic interplay need yet
to be established. Drawing on various physiological and anatomical data, we
elaborate the novel hypothesis that the visual cortex controls the
spatiotemporal structure of cortical receptive fields via feedback to the
lateral geniculate nucleus. Furthermore, we present and analyze a model of
corticogeniculate loops that implements this control, and exhibit its ability
of object segmentation by statistical motion analysis in the visual field.
