Byrne & Russon provide illustrative examples of imitative abilities in nonhuman primates. The convincing aspects of the examples are not, however, their hierarchical or structured nature: Such organization may be inevitable and hence, does not require explanation via imitation. Rather, examples of imitation are derived from reproduction of behaviors and sequences that, from the organism's perspective, are arbitrary.

Recently, βIII spectrins have been recognized as ataxia disease genes, with the identification by Ikeda and co‐workers of pathogenic mutations in the SPTBN2 gene in three large (and mapped) SCA5 families of American and European origin.(1) With their discovery, the large “Lincoln” family has been traced back to the underlying genetic defect for the slowly progressive cerebellar ataxia. In addition, the involvement of this component of the cytoskeleton directs attention towards the possible role of organelle stability during neurodegeneration. The findings (...) suggest that the mechanical properties of neurons and their dynamics may be as important as altered Ca2+ homeostasis, transcriptional dysregulation, and impaired protein degradation in neurodegeneration conditions. BioEssays 28: 785–787, 2006. © 2006 Wiley Periodicals, Inc. (shrink)