![]() This methodology provided a crucial tool for studying in detail the role of the distinct visual areas in visual information processing. With such an approach, the functional topography of early visual areas could be objectively mapped in individual human subjects and compared to topography of areas in the monkey visual cortex ( Van Essen, 2004). Because adjacent areas have opposite representations of the retinal image, the area borders can be outlined by calculating the sign of the local visual field ( Sereno et al., 1995). Functional magnetic resonance imaging (fMRI) has enabled mapping of the retinotopic organization in the human visual cortex in vivo and non-invasively ( Engel et al., 1994 Sereno et al., 1995 Goebel et al., 1998). Research into the visual system is a prominent example where such an approach has been successful. Furthermore, such a parcellation is crucial for understanding homologies and differences between human and animal cortex. Establishing an accurate parcellation of the cortical areas is thus essential in human research for studying the functional role of the various areas and for comparing results across experiments and laboratories. Whereas in animal models the link between micro-structural and functional properties of an area can be studied directly and in the same individual animal, in non-invasive research in humans such a link is much more labile, as it relies on the gross correspondence to macro-anatomical landmarks or matching to probabilistic atlases derived from post-mortem analysis of different brains ( Morosan et al., 2001). Introduction: Challenges for the Investigation of the Human Auditory CortexĪ major scientific approach in brain research has been to divide the cortex into smaller anatomical areas based on their micro-structural properties ( Brodmann, 1909 Zilles and Amunts, 2009 Nieuwenhuys, 2012) and examine each area's functional properties through the analysis of the responses of neurons and neuronal populations. We propose and discuss a topography of areas that is consistent with old and recent anatomical post-mortem characterizations of the human auditory cortex and that may serve as a working model for neuroscience studies of auditory functions. Furthermore, we show that considering multiple maps indicative of anatomical (i.e., myelination) as well as of functional properties (e.g., broadness of frequency tuning) is helpful in identifying auditory cortical areas in individual human brains. Importantly, we illustrate that-whereas a group-based approach to analyze functional (tonotopic) maps is appropriate to highlight the main tonotopic axis-the examination of tonotopic maps at single subject level is required to detail the topography of primary and non-primary areas that may be more variable across subjects. ![]() Here, we propose a topography of the human auditory areas based on insights on the anatomical and functional properties of human auditory areas as revealed by studies of cyto- and myelo-architecture and fMRI investigations at ultra-high magnetic field (7 Tesla). While advances in magnetic resonance imaging (MRI) throughout the last decades have enabled the detailed anatomical and functional inspection of the human brain non-invasively, to date there is no consensus regarding the precise subdivision and topography of the areas forming the human auditory cortex. 3Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA.2Maastricht Brain Imaging Center, Maastricht University, Maastricht, Netherlands.1Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands.Michelle Moerel 1,2,3 Federico De Martino 1,2 Elia Formisano 1,2 *
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