A renewed interest in understanding the human connectome offers a novel platform to investigate the relationship between brain organization and behaviour. While much has already been learned about the organization of the brain in non-human species by looking at connectivity between neurons, the non-invasive tools to make this fruitful area of research possible in humans have only widely emerged in the past decade. The research group “Neuroanatomy & Connectivity” aims to make a unique contribution to this research endeavour by applying non-invasive connectivity mapping techniques to describing the organization of the prefrontal cortex in humans.

Numerous subdivisions within the prefrontal cortex have been described in the macaque monkey based on unique patterns of connectivity. Nonetheless, their translation to understanding the organization of the human brain remains speculative. In collaboration with Michael Petrides, an expert in cross-species prefrontal anatomy from the Montreal Neurological Institute, we will map these same areas in the human brain using hypotheses generated from the broad tract-tracing literature from the macaque monkey. Specifically, we will focus on functional connectivity using correlations of intrinsic brain activity as measured with fMRI during the “resting-state”. Intrinsic functional connectivity, which is based on the spontaneous synchronization of activity between regions, has been found to accurately characterize widespread functionally congruous brain systems. In previous work, we have demonstrated that intrinsic functional connectivity can be a powerful tool for mapping subdivisions in cortical areas (Margulies et al, NeuroImage, 2007), can be demonstrated as well in macaque monkeys, and largely reflects predictions from the tract-tracing literature (Margulies et al, PNAS, 2009). Furthermore, the patterns are reliable (Shehzad et al, Cerebral Cortex, 2009), and detectable on the individual level. In addition, this initial aim of mapping functional connectivity-based subdivisions within the prefrontal cortex will integrate complementary approaches from anatomical connectivity measures such as probabilistic tractography (based on diffusion tensor imaging data) as well as meta-analyses of task studies (thereby aiming to ascribe putative functional roles to regions and networks described through the above methods).

The second main line of research will focus on the variability in prefrontal anatomy across individuals. How do differences in structure contribute to differences in individual behavior and cognition? Using large-scale datasets of brain and phenotypic information, we will investigate these correspondences, as they relate to the aforementioned subdivisions. Finally, the malleability of prefrontal networks will be the topic of our third line of research. As our surroundings play a significant role in determining our individual behavior: how do environmental influences and recent experiences impact on functional brain architecture? To address this question, we will assess the impact of contextual priming and learning on prefrontal organization. In this initial phase, we will begin data collection for the brain-phenotypic studies, as well data collection for a small cohort of highly characterized subjects for anatomical studies.