Volumetric measurements of neopallium and frontal lobe white and grey matter.

Species #: identification number of the individual used in the collection; N: neopallium; w: white matter; g: grey matter; FR: frontal neopallial lobe; Brain: total brain volume; BG: basal ganglia. The ratio of frontal lobe relative to neopallium are indicated for the current study and for the analyses done on different individuals by Semendeferi et al (1997) and Semendeferi et al. (2002). Basal ganglia is measured as the sum of its two largest constituent parts (striatum and pallidum) that are also responsible for (respectively) the primary input from neopallium and primary output to other brain structures. Volumetric data for substantia nigra and subthalamic nucleus (the two other, but significantly smaller, constituent parts of the basal ganglia) are not available for the individuals used in the current analysis. Data from Stephan (unpublished) comprises the individual-specific data underlying the data presented in Stephan et al. [37] and was made available by H. Frahm. Data on brain size from Pan paniscus and Pongo pygmaeus, however, comes from Macleod et al. [61].