* Heterarchy might be a better description than hierarchy.Anki is a free flashcard app that uses active recall and spaced repetition. Barbas H, Rempel-Clower N (1997) Cortical structure predicts the pattern of corticocortical connections. Dombrowski SM, Hilgetag CC, Barbas H (2001) Quantitative architecture distinguishes prefrontal cortical systems in the rhesus monkey. Similar neighborhoods would have one type of linkage (the “symmetric” type), whereas dissimilar neighborhoods would have another (the “asymmetric” type). If the structural model were true for cities, then neighborhoods that have similar houses and street layouts would be more closely linked that dissimilar neighborhoods. To return to the city analogy, the structural model tells us that we can infer the (transportation/social/cultural?) links between pairs of neighborhoods based on what the two neighborhoods look like. When it is out I will append it to this answer. My boss, Helen Barbas, just submitted a short review about the structural model. įor more on the details of the model, check out the references. Projections from a more differentiated area to a less differentiated area have the opposite pattern: they originate in superficial layers (2 and 3), and terminate in deep layers (4,5 and 6). Dissimilar areas are generally more weakly connected, and have an “asymmetric” laminar pattern of connections, in which projections from a less differentiated area to a more differentiated area originate in deep layers (5 and 6), and terminate in superficial layers (1,2 and 3). Areas which are similar tend to be more strongly connected to each other, with many layers linking to each other in a way that can be described as “columnar”, “lateral” or “symmetric”. Įvery functional cortical hierarchy* consists of a spectrum of cortices from limbic to eulaminate areas. Schematic representation of cortico-cortical projections. They don’t have a naming/addressing system, but at least they provide a way to make sense of the forest of areas!įig 2. Over the years my lab - the Neural Systems Laboratory at Boston University - has developed a structural model that explains cortical areas and their interconnections in terms of cytoarchitectonic features. Only instead of a 2D city, neuroanatomists are mapping a 3D planet! Over time they learn the Brodmann area numbers. The landmarks for neuroanatomists are sulci and gyri. Boston, where I live, is largely lacking in regularity, so one really has to use landmarks - like the Charles River, the Citgo sign, or the Prudential Center. Think of it like this: what they’re doing is like navigating a city that doesn’t have a neat New York -style city block structure with sensibly numbered streets and avenues. Neuroanatomists become familiar with the brain’s geography over years and years of “travel” through the brain. I’m a computational modeler working in an anatomy lab, so I confront the deficits in my anatomical knowledge on a daily basis! I can barely remember the handful of Brodmann areas relevant to my project, let alone the full list! I have a diagram of the areas taped up next to my monitor. The Brodmann numbering system for cortical areas is arbitrary. The question details added the following comment: “Brodmann area 7 is honestly where the numbering starts to seem really arbitrary.” Here’s how I responded: I was asked the following question on Quora: “How do you most easily memorize Brodmann’s areas?”.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |