What is where and why it is important

Abstract

The paper by Devlin and Poldrack entitled 'In praise of Tedious Anatomy' deals with an increasingly important topic. Namely, how do we effectively communicate, with appropriate accuracy and precision, the 'where' of our measurements? They make cogent arguments for the use of anatomical maps to reference the location of functionally active regions of brain as measured with fMRI. We agree with this premise and would like to amplify further (with some additional suggestions) the rationale for equating functional measures with observations about structure. But before we do that, it might be useful to first generalize this issue, as one that pertains to 1) comparing data collected across multiple subjects, modalities, experiments and laboratories and 2) integrating this data as a comprehensive whole.Specifying the site of activation, in anatomic terms, is intended (in part) to provide the ability to compare and contrast different studies. The notion of an atlas is, among other things, to help with this localization. Unfortunately many anatomic terms are sometimes interpreted variably and the boundaries of anatomic regions are sometimes in dispute. Given the mostly descriptive history of anatomy, its application, in a traditional sense, to modern volumetric MRI surveys of the brain sometimes produces more problems than it solves. Atlases such as the (Talairach and Tournoux, 1988) are woefully inadequate as an anatomic reference but did encourage the use and further development of spatial normalization schemes to reduce size and shape variability of brains. Other atlases such as (Ono et al., 1990) and (Duvernoy, 1991 provide far more complete and detailed delineations but either do not provide any principles or algorithms for spatial normalization or Cartesian coordinate systems. And finally, the question of how a single brain based atlas can represent a population is rarely argued anymore. Describe Where you areWhat then can facilitate this need to compare and contrast brain image data? We believe this requires more complete descriptions. Just as when we give directions to our house we might say, "… the address is 123 Main street, it's the third house on the left after the intersection, it's a white house with a porch, two stories tall…", etc. If using certain Global Positioning Systems (GPS) we might specify the latitude and longitude, in coordinates. We provide several ways to locate and identify the house. The different descriptions, collectively, make it easy to find and often compare it to others that may be geographically close. In brain mapping, this is difficult because often the only reference we have is an accompanying macroscopic structural MRI. So we might say the site of activation is in Brodmann area 46 or Talairach and Tournoux coordinate (x,y,z) or in the pars opercularis of the inferior frontal gyrus. We might say the

Quantifying the heritability of task-related brain activation and performance during the N-back working memory task: A twin fMRI study

“…Also, we used a probabilistic atlas to attribute activation in a voxel to the most likely cytoarchitectonic area, compared with the use of single-subject atlases, which can be misleading for anatomical localisation in group data (Devlin and Poldrack, 2007;Toga and Thompson, 2007). Indeed, in comparing the hippocampal coordinates used by Egan et al (2003) with the LONI probabilistic brain atlas that we used, most of the coordinates were not in the hippocampus, but more likely in the putamen, parahippocampal gyrus or middle temporal gyrus.…”

Different patterns of cerebral activation in genuine and malingered cognitive effort during performance on the Word Memory Test

“…Subjects were not stratified by any other cognitive measure, with the assumption that all had normal cognitive ability. Since level of intellectual ability may relate to fMRI activation patterns [54] this would have to be considered in future studies. The malingering condition was simulated and no subject was actually in litigation.…”

Whole Brain Magnetic Resonance Image Atlases: A Systematic Review of Existing Atlases and Caveats for Use in Population Imaging

“…It has been used to describe the site of a biopsy, or to compare data from structural MRI, functional MRI (fMRI), SPECT, and PET studies. However, the Talairach and Tournoux atlas has been described as “woefully inadequate” (Toga and Thompson, 2007). The reasons for this, including that it was derived from a single fixed cadaveric brain from an elderly female with limited clinical information, have been listed by many and well-known since the atlases' inception (Evans et al, 1993, 2012; Devlin and Poldrack, 2007).…”