title: Neocortical calretinin neurons in primates: increase in proportion and microcircuitry structure.
abstract: In this article we first point at the expansion of associative cortical areas in primates, as well as at the intrinsic changes in the structure of the cortical column. There is a huge increase in proportion of glutamatergic cortical projecting neurons located in the upper cortical layers (II/III). Inside this group, a novel class of associative neurons becomes recognized for its growing necessity in both inter-areal and intra-areal columnar integration. Equally important to the changes in glutamatergic population, we found that literature data suggest a 50% increase in the proportion of neocortical GABAergic neurons between primates and rodents. This seems to be a result of increase in proportion of calretinin interneurons in layers II/III, population which in associative areas represents 15% of all neurons forming those layers. Evaluating data about functional properties of their connectivity we hypothesize that such an increase in proportion of calretinin interneurons might lead to supra-linear growth in memory capacity of the associative neocortical network. An open question is whether there are some new calretinin interneuron subtypes, which might substantially change micro-circuitry structure of the primate cerebral cortex.
authors.affiliation: Laboratory for Neuromorphometry, Department of Neuroscience, Croatian Institute for Brain Research, School of Medicine, University of Zagreb Zagreb, Croatia.
authors.forename: Domagoj
authors.initials: D
authors.lastname: Džaja
authors.affiliation: Department of Anatomy and Clinical Anatomy, School of Medicine, University of Zagreb Zagreb, Croatia.
authors.forename: Ana
authors.initials: A
authors.lastname: Hladnik
authors.affiliation: Department of Anatomy and Clinical Anatomy, School of Medicine, University of Zagreb Zagreb, Croatia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Bičanić
authors.affiliation: Institute of Forensic Medicine and Criminalistics, School of Medicine, University of Zagreb Zagreb, Croatia.
authors.forename: Marija
authors.initials: M
authors.lastname: Baković
authors.affiliation: Laboratory for Neuromorphometry, Department of Neuroscience, Croatian Institute for Brain Research, School of Medicine, University of Zagreb Zagreb, Croatia ; Department of Anatomy and Clinical Anatomy, School of Medicine, University of Zagreb Zagreb, Croatia.
authors.forename: Zdravko
authors.initials: Z
authors.lastname: Petanjek
keywords: GABA; calretinin; neocortex; pyramidal neurons; species differences