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1.  Transgenic Quail as a Model for Research in the Avian Nervous System – A Comparative Study of the Auditory Brainstem 
Research performed on transgenic animals has led to numerous advances in biological research. However, using traditional retroviral methods to generate transgenic avian research models has proven problematic. As a result, experiments aimed at genetic manipulations on birds remained difficult for this popular research tool. Recently, lentiviral methods have enabled production of transgenic birds, including a transgenic Japanese quail (Coturnix coturnix japonica) line showing neuronal-specificity and stable expression of eGFP across generations (termed here as GFP quail). To test whether the GFP quail may serve as a viable alternative to the popular chicken model system, with the additional benefit of gene manipulation, we compared the development, organization, structure and function of a specific neuronal circuit in chicken (Gallus gallus domesticus) to that of the GFP quail. This study focuses on a well-defined avian brain region, the principal nuclei of the sound localization circuit in the auditory brainstem, nucleus magnocellularis (NM) and nucleus laminaris (NL). Our results demonstrate that structural and functional properties of NM and NL neurons in the GFP quail, as well as their dynamic properties in response to changes in the environment, are nearly identical to those in chickens. These similarities demonstrate that the GFP quail, as well as other transgenic quail lines, can serve as an attractive avian model system, with the advantage of being able to build on the wealth of information already available from the chicken.
doi:10.1002/cne.23187
PMCID: PMC3488602  PMID: 22806400
transgenic quail; auditory brainstem
2.  Topography and Morphology of the Inhibitory Projection From Superior Olivary Nucleus to Nucleus Laminaris in Chickens (Gallus gallus) 
The avian nucleus laminaris (NL) is involved in computation of interaural time differences (ITDs) that encode the azimuthal position of a sound source. Neurons in NL are bipolar, with dorsal and ventral dendritic arbors receiving input from separate ears. NL neurons act as coincidence detectors that respond maximally when input from each ear arrives at the two dendritic arbors simultaneously. Computational and physiological studies demonstrated that the sensitivity of NL neurons to coincident inputs is modulated by an inhibitory feedback circuit via the superior olivary nucleus (SON). To understand the mechanism of this modulation, the topography of the projection from SON to NL was mapped, and the morphology of the axon terminals of SON neurons in NL was examined in chickens (Gallus gallus). In vivo injection of AlexaFluor 568 dextran amine into SON demonstrated a coarse topographic projection from SON to NL. Retrogradely labeled neurons in NL were located within the zone of anterogradely labeled terminals, suggesting a reciprocal projection from SON to NL. In vivo extracellular physiological recording further demonstrated that this topography is consistent with tonotopic maps in SON and NL. In addition, three-dimensional reconstruction of single SON axon branches within NL revealed that individual SON neurons innervate a large area of NL and terminate on both dorsal and ventral dendritic arbors of NL neurons. The organization of the projection from SON to NL supports its proposed functions of controlling the overall activity level of NL and enhancing the specificity of frequency mapping and ITD detection.
doi:10.1002/cne.22523
PMCID: PMC3299086  PMID: 21165979
auditory brainstem; axonal projection; γ-aminobutyric acid (GABA); interaural time difference (ITD); tonotopic organization

Results 1-2 (2)