The principal brain regions involved in language production include the inferior frontal gyrus and the anterior insula. To date, there have been few neuroanatomical investigations of these regions in humans and even fewer studies involving multiple species. Additional neuroanatomical data on humans and their closest relatives would enhance our scientific understanding of changes in cognition and language throughout human evolution. Similarly, additional cross-species data would enhance existing debates concerning possible differences in cognitive capabilities among primate species.
This study will analyze the inferior frontal gyrus and the anterior insula at microstructural and macrostructural levels in multiple primate species, including humans, chimpanzees and macaques. The data from this study will not only contribute to the understanding of human and primate evolution, but will also facilitate an understanding of how language is organized in the human brain. Greater understanding of language organization can aid in the study and treatment of speech pathologies such as stuttering. Furthermore, the data from additional species, such as the apes, will facilitate the interpretation of findings from human imaging studies and those from experimental studies of macaques.
A key component of the proposed project is the training of the co-principal investigator in a variety of techniques (including stereology, neurochemistry and magnetic resonance imaging) that are important in the study of neuroanatomy. This learning and training will take place in selected laboratories in the United States and Germany that have previously analyzed some of the regions of interest in individual species. These activities will not only serve to train the co-principal investigator, but will also serve to enhance collaborative networks and partnerships among several laboratories currently working on issues relating to primate brain evolution.
