What should inter-individual and inter-primate differences tell us about auditory cortical organization?
* Presenting author
Our current conceptualization of human auditory cortical organization is largely based on a synthesis of results from a relatively small number of exceptionally detailed electrophysiological and histology studies in macaque, owl, and squirrel monkey from the 1970s-early 2000s. Such a synthesis requires mentally quilting together small, partially overlapping patches of mapped cortex from multiple individuals, with the necessary assumption that individuals within a species - and across related species - share a common organizational scheme. This approach has been quite successful in predicting patterns of human auditory regionalization as shown in fMRI and electrocorticography studies. However, the power of MRI to image all of cortex in many individuals at multiple timepoints has also shown that the topography of tonotopic and inferred 'myelin maps' can vary considerably across people, and even between the two hemispheres of a single person. Here, we compare individual auditory maps from a large (>50) combined tonotopy and multiparameter map study to each other, and to previously published human and non-human primate auditory maps and theoretical schemes. We show there is significantly more 'true' variability in auditory organization than is generally appreciated, and suggest ways that such variability can inform models of cortical development and regionalization.