Dendritic orientation and laminar architecture in the rabbit auditory thalamus.

Full Abstract

A laminar organization composed of the dendritic fields of principal neurons and afferent axonal arbors has been proposed as the anatomical substrate for the frequency map at several levels of the mammalian central auditory system, including the inferior colliculus and medial geniculate body (MGB). In contrast to the auditory thalamus in most mammals, the ventral division of the rabbit medial geniculate body (MGV) has cellular laminae visible in routine Nissl stains, allowing a direct comparison of the laminar organization with the dendritic architecture and frequency organization. In total 30 presumptive relay neurons in the MGV were labeled with the juxtacellular recording method, and their dendritic arbors were fully reconstructed from serial sections with the aid of a computer microscope. The spatial organization of MGV dendritic fields was analyzed using the dendritic prism, dendritic stick, and fan-in projection methods. Quantitative spatial analyses revealed that, for MGV neurons in the central pars lateralis subdivision, the major axis of the dendritic fields (approximately 29 degrees relative to the horizontal plane) was closely aligned with that of the Nissl laminae (approximately 25 degrees). Both were oriented orthogonally to the tonotopic axis. In contrast, cells in the pars ovoidea had their major axis of orientation parallel to the anteroposterior axis of the brain. Although a bitufted dendritic field was the norm, it was not uncommon for MGV neurons to have pronounced spatial asymmetries in their dendritic fields. A model is presented that incorporates cellular laminae and oriented dendritic growth to form frequency-related slabs within the MGV. Copyright 2003 Wiley-Liss, Inc.

Author information

Author/s: Cetas, Justin S (JS); Price, Robin O (RO); Crowe, Jennifer (J); Velenovsky, David S (DS); McMullen, Nathaniel T (NT);

Affiliation: Department of Cell Biology and Anatomy, University of Arizona College of Medicine, Tucson, Arizona 85724, USA.

Grants: DC02410 (Agency:NIDCD NIH HHS) ; NS07434 (Agency:NINDS NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.

Journal: The Journal of comparative neurology (J Comp Neurol), published in United States. (Language: eng)

Reference: 2003-Apr; vol 458 (issue 3) : pp 307-17

Dates: Created 2003/03/05; Completed 2003/04/18; Revised 2007/11/14;

PMID: 12619083, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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