Hominin paleoneurology: where are we now?

Hominin paleoneurology is the subfield of paleoanthropology that investigates brain evolution in human ancestors. For over a century, paleoneurologists have focused on analyses of cranial capacities (as surrogates for brain size) and endocranial casts (endocasts), which are prepared from the interiors of fossilized braincases and reproduce details of external brain morphology. This review discusses recent improvements in our understanding of hominin brain evolution in terms of brain size, sulcal patterns, and cortical shape features. To the extent possible, the evolution of neurological reorganization is assessed in light of findings from paleoneurology. In order to make inferences about cognitive evolution, paleoneurologists interpret their data within a framework that incorporates behavioral information from comparative primatological studies and findings from comparative neuroanatomical and medical imaging investigations. Advances in our knowledge about the evolution of the prefrontal cortex (Brodmann's area 10) provide an example of a productive synthesis of comparative neuroanatomical and behavioral research with investigations of the fossil record of hominin endocasts.