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A Weighted and Directed Interareal Connectivity Matrix for Macaque Cerebral Cortex

2012; Oxford University Press; Volume: 24; Issue: 1 Linguagem: Inglês

10.1093/cercor/bhs270

1460-2199

Nikola T. Markov, Mária Ercsey-Ravasz, Ana Rita Ribeiro Gomes, Camille Lamy, Loïc Magrou, Julien Vezoli, Pierre Misery, Arnaud Falchier, René Quilodran, Marie-Alice Gariel, Jérôme Sallet, Răzvan Gămănuț, Cyril Huissoud, Simon Clavagnier, Pascale Giroud, Dominique Sappey‐Marinier, Pascal Barone, Colette Dehay, Zoltán Toroczkai, Kenneth Knoblauch, David C. Van Essen, Henry Kennedy,

Advanced Neuroimaging Techniques and Applications

Retrograde tracer injections in 29 of the 91 areas of the macaque cerebral cortex revealed 1,615 interareal pathways, a third of which have not previously been reported. A weight index (extrinsic fraction of labeled neurons [FLNe]) was determined for each area-to-area pathway. Newly found projections were weaker on average compared with the known projections; nevertheless, the 2 sets of pathways had extensively overlapping weight distributions. Repeat injections across individuals revealed modest FLNe variability given the range of FLNe values (standard deviation <1 log unit, range 5 log units). The connectivity profile for each area conformed to a lognormal distribution, where a majority of projections are moderate or weak in strength. In the G29 × 29 interareal subgraph, two-thirds of the connections that can exist do exist. Analysis of the smallest set of areas that collects links from all 91 nodes of the G29 × 91 subgraph (dominating set analysis) confirms the dense (66%) structure of the cortical matrix. The G29 × 29 subgraph suggests an unexpectedly high incidence of unidirectional links. The directed and weighted G29 × 91 connectivity matrix for the macaque will be valuable for comparison with connectivity analyses in other species, including humans. It will also inform future modeling studies that explore the regularities of cortical networks.