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CCN Brown Bag Series

Wednesday, November 14, 2018,
  • Location: Wilson Hall • 111 21St Ave S • Nashville, TN 37240
  • Room: 115

Claus Hilgetag, PhD

Department of Computational Neuroscience

University Medical Center Hamburg-Eppendorf

"An architectonic type principle integrates cerebral cortical architecture and connectivity"

The connections that link neurons within as well as between cerebral cortical areas form a multi-scale structural network for communication in the brain. Which principles underlie the organisation of this complex network? Our recent work has addressed this question by systematically investigating the relation of essential features of cortico-cortical connections, such as their presence or absence as well as patterns of laminar projection origins and terminations, to fundamental structural parameters of cortical areas, such as their distance, similarity in cortical cytoarchitecture as defined by cortical lamination or neuronal density, as well as similarity in macroscopic and microscopic morphological features. These systematic analyses demonstrate the presence of an architectural type principle of cortical connections.  Across different species (primate, cat, mouse, human) and different cortical lobes, the essential features of cortico-cortical connections vary consistently and strongly with the cytoarchitectonic similarity of cortical areas.  By contrast, such relations were not found consistently for distance, similarity of cortical thickness or cellular morphological features.  Moreover, intrinsic brain architecture as characterised by architectural type and neural density also accounted for cellular neuronal features, such as cell size or shape.  The robustness of the findings across mammalian brains allows direct cross-species predictions of the existence and laminar patterns of projections, including for the human brain, where such data are not directly available experimentally. Cortical gradients in architectural types also determine the specific organisation of the local micro-circuits of different areas. Therefore, these findings illuminate a general principle of neural wiring, linking the organization of macroscopic cortical connections to intrinsic circuits of the cerebral cortex. This architectonic type principle integrates cortical connectivity and architecture across scales of organisation, with implications for cortical physiology as well as for developmental mechanisms.

 

Key words:

brain architecture, cytoarchitecture, cortical gradients, microcircuits, laminar projections, neuron density