The dorsomedial and dorsolateral forebrain of the zebra finch, Taeniopygia guttata: a Golgi study

Abstract

Neurones in the zebra finch dorsal forebrain (hippocampal and lateral corticoid complexes) were described and located using Golgi methods. We distinguish two main classes of neurones, spinous with distant projecting axons, and aspinous with local axons. Spinous neurones are subclassified into bitufted pyramids, localised in the medial hippocampus, modified bitufted pyramids in the intermediate corticoid area, multipolar neurones in the parahippocampal area, lateral hippocampus and corticoid complex, and stellate neurones in the corticoid complex. Among the aspinous neurones, we distinguish neurones with basket axons, dense pericellular axons, radial axons, and net-like axons, and horizontal cells seen in the dorsolateral corticoid area. This group includes sparsely spinous neurones found in the intermediate corticoid area. On the basis of the neuronal characteristics, we divide the hippocampal complex into 5 fields: medial and lateral hippocampus, parahippocampal area, central field of the parahippocampal area, and crescent field. The lateral corticoid complex is subdivided into an intermediate corticoid area and a dorsolateral corticoid area. We conclude that the avian dorsal forebrain is an assembly of fields interconnected by axonal collaterals. The medial hippocampus and possibly the intermediate corticoid area display a primitive cortex-like organisation, whereas the other fields lack any sign of cortical structure.

Efferent connectivity of the hippocampal formation of the zebra finch (Taenopygia guttata): An anterograde pathway tracing study usingPhaseolus vulgaris leucoagglutinin

“…Following iontophoresis, the skin was sutured, and the birds were allowed to recover in a hospital cage until their balance and flying abilities were normal. between these subdivisions and those of the mammalian hippocampus have used cytoarchitectural (Montagnese et al, 1996) and immunocytochemical Krebs et al, 1991) landmarks. In the present paper, we describe the efferent connections of the zebra finch HP by using Phaseolus vulgaris leucoagglutinin (PHAL), a sensitive anterograde tracer, to complement these other approaches.…”

The CA3 network as a memory store for spatial representations

“…Unfortunately, staining the avian brain for the distribution of Zinc with the Timm stain, which in mammals and reptiles stains the projection from neurons in the granular cell layer to a group of large pyramidal cells, does not provide useful clues. In birds the Timm stain only results in rather diffuse and weak staining (Faber et al 1989;Montagnese et al 1993Montagnese et al , 1996.…”

Contribution of Genoarchitecture to Understanding Hippocampal Evolution and Development

“…Birds, particularly flying birds, have remarkable navigation abilities and the interest on their HF has justified numerous studies on its anatomical and neurochemical organization, connections and function [Benowitz and Karten, 1976;Bingman et al, 1984Bingman et al, , 2003Casini et al, 1986;Erichsen et al, 1991;Montagnese et al, 1996;Székely and Krebs, 1996;Colombo and Broadvent, 2000;Atoji et al, 2002;Atoji and Wild, 2004;Suárez et al, 2006;Mayer et al, 2013;Herold et al, 2014]. Some of these studies have led to various proposals of subdivisions [reviewed by Suárez et al, 2006] and to the finding of serial projections between several hippocampal and APH [Atoji and Wild, 2004].…”