| In primates,Besides the traditional visual stream which is through LGN and V1,pulvinar nuclei also play a very important role for delivery the visual information,it is the bridge between the SC and the visual cortex.The pulvinar complex of primates has been implicated in playing an important role in visual processing especially the lateral pulvinar(PL)and central lateral inferior pulvinar(PIcl).The PL and PIcl send afferent projections into thin and thick stripes of V2 in primates,but the thin and thick stripes of V2 process different visual information,Right now no evidence to certify how the projection distributed in the PL and PIcl,and its physiological and anatomical characteristics remain to be elucidated.Guided by conventional intrinsic signal optical imaging method,we identified the map of V2 sub-compartments,and three types of retrograde tracers(CTB-488,CTB-555 and BDA)were injected into different stripes of V2 and then identify the retrograde signal in pulvinar.Surprisingly,we found at least five topographically organized clusters of labeling in the pulvinar,there was little overlap of tracer signals at a single cell level,indicating the presence of more than two V2-projecting maps.Our results suggest that the PL/PIcl exhibits greater compartmentalization than previously thought.They may be functionally similar but participate in multiple cortico-pulvinar-cortical loops.Our results provide clues for future physiological studies to reveal the functional roles of the pulvinar in visual processing. |
