title: The evolution of prefrontal inputs to the cortico-pontine system: diffusion imaging evidence from Macaque monkeys and humans.
abstract: The cortico-ponto-cerebellar system is one of the largest projection systems in the primate brain, but in the human brain the nature of the information processing in this system remains elusive. Determining the areas of the cerebral cortex which contribute projections to this system will allow us to better understand information processing within it. Information from the cerebral cortex is conveyed to the cerebellum by topographically arranged fibres in the cerebral peduncle - an important fibre system in which all cortical outputs spatially converge on their way to the cerebellum via the pontine nuclei. Little is known of their anatomical organization in the human brain. New in vivo diffusion imaging and probabilistic tractography methods now offer a way in which input tracts in the cerebral peduncle can be characterized in detail. Here we use these methods to contrast their organization in humans and macaque monkeys. We confirm the dominant contribution of the cortical motor areas to the macaque monkey cerebral peduncle. However, we also present novel anatomical evidence for a relatively large prefrontal contribution to the human cortico-ponto-cerebellar system in the cerebral peduncle. These findings suggest the selective evolution of prefrontal inputs to the human cortico-ponto-cerebellar system.
authors.affiliation: Cognitive Neuroscience Laboratory, Department of Psychology, Royal Holloway University of London, UK. n.ramnani@rhul.ac.uk
authors.forename: Narender
authors.initials: N
authors.lastname: Ramnani
authors.forename: Timothy E J
authors.initials: TE
authors.lastname: Behrens
authors.forename: Heidi
authors.initials: H
authors.lastname: Johansen-Berg
authors.forename: Marlene C
authors.initials: MC
authors.lastname: Richter
authors.forename: Mark A
authors.initials: MA
authors.lastname: Pinsk
authors.forename: Jesper L R
authors.initials: JL
authors.lastname: Andersson
authors.forename: Peter
authors.initials: P
authors.lastname: Rudebeck
authors.forename: Olga
authors.initials: O
authors.lastname: Ciccarelli
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Richter
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Thompson
authors.forename: Charles G
authors.initials: CG
authors.lastname: Gross
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Robson
authors.forename: Sabine
authors.initials: S
authors.lastname: Kastner
authors.forename: Paul M
authors.initials: PM
authors.lastname: Matthews
mesh_terms: D000328:Adult; D000818:Animals; D005075:Biological Evolution; D002525:Cerebellar Cortex / Q000166:cytology*; D005260:Female; D006801:Humans; D008252:Macaca fascicularis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009434:Neural Pathways / Q000166:cytology; D011149:Pons / Q000166:cytology*; D017397:Prefrontal Cortex / Q000166:cytology*; D013045:Species Specificity