A way of selectively degrading colour constancy demonstrates the experience dependence of colour vision

the star appendages reveals that a large proportion of somatosensory cortex is devoted to the star, and within the star representation the tactile fovea takes up a disproportionate amount of cortex for its size. The larger representation of the 11th, foveal appendage does not reflect the number of sensors or nerve fibers from this area, but instead seems to reflect the behavioral importance of the touch fovea. How did the star evolve? The star is unparalleled in mammalian anatomy, and so it is natural to wonder how such a complicated new structure evolved. There are no fossil noses to examine, but there is a wealth of information to be found in comparative studies of living moles and studies of star-nosed mole development. Examination of mole embryos reveals a remarkable developmental sequence for the star, during which the appendages form in place on the side of the face, and later 'peel' off the face to form forward facing extensions. This developmental sequence is unlike that of any other animal appendage, and a number of stages are arguably 'inefficient' when compared to the more straightforward mechanism of body wall outgrowth seen for other animal appendages. But some living mole species, such as the Coast mole, Scapanus orarius, have a proto-star consisting of backward facing, short modules of sensory organs attached to the side of their snout. This suggests that evolution 'tinkered' with such a structure in ancestral moles to arrive at the full-fledged star — leaving a trail of evidence in the unusual developmental sequence. The development of a biological novelty: A different way to make appendages as revealed in the snout of the star-nosed mole (Condylura cristata). Somatosensory fovea in the star-nosed mole: Behavioral use of the star in relation to innervation patterns and cortical representation. A section of the flattened neocortex processed for metabolic enzyme cytochrome oxidase showing the area where touch information from the star projects. The 11 modules in the cortex each represent one of the 11 appendages of the contralateral side of the star. Note the greatly expanded representation of the tactile fovea (appendage 11). A scanning electron micrograph of an embryonic star-nosed mole showing the nascent star. The appendages develop attached to the side of the face and later peel off to form the adult star. This unusual developmental sequence provides clues to the star's evolution. A study reported recently in Current Biology [1] shows that …