A systems and neurobiological model of nucleus angularis and nucleus laminaris in the barn owl

2004 ◽  
Vol 116 (4) ◽  
pp. 2599-2599
Author(s):  
Brian J. Fischer ◽  
Charles H. Anderson
Keyword(s):  
Barn Owl ◽  
Nucleus Laminaris ◽  
Neurobiological Model ◽  
Nucleus Angularis

scholarly journals Maps of interaural delay in the owl's nucleus laminaris

2015 ◽  
Vol 114 (3) ◽  
pp. 1862-1873 ◽  
Author(s):  
Catherine E. Carr ◽  
Sahil Shah ◽  
Thomas McColgan ◽  
Go Ashida ◽  
Paula T. Kuokkanen ◽  
...  
Keyword(s):  
Conduction Velocity ◽  
Delay Line ◽  
Field Potential ◽  
Barn Owl ◽  
Conduction Delay ◽  
Interaural Time Differences ◽  
Nucleus Laminaris ◽  
Nucleus Magnocellularis

Axons from the nucleus magnocellularis form a presynaptic map of interaural time differences (ITDs) in the nucleus laminaris (NL). These inputs generate a field potential that varies systematically with recording position and can be used to measure the map of ITDs. In the barn owl, the representation of best ITD shifts with mediolateral position in NL, so as to form continuous, smoothly overlapping maps of ITD with iso-ITD contours that are not parallel to the NL border. Frontal space (0°) is, however, represented throughout and thus overrepresented with respect to the periphery. Measurements of presynaptic conduction delay, combined with a model of delay line conduction velocity, reveal that conduction delays can account for the mediolateral shifts in the map of ITD.

scholarly journals Connections of the auditory brainstem in a Songbird,Taeniopygia guttata.I. Projections of nucleus angularis and nucleus laminaris to the auditory torus

2010 ◽  
Vol 518 (11) ◽  
pp. 2109-2134 ◽  
Author(s):  
Nils O.E. Krützfeldt ◽  
Priscilla Logerot ◽  
M. Fabiana Kubke ◽  
J. Martin Wild
Keyword(s):  
Auditory Brainstem ◽  
Nucleus Laminaris ◽  
Nucleus Angularis

scholarly journals In vivo Recordings from Low-Frequency Nucleus Laminaris in the Barn Owl

2015 ◽  
Vol 85 (4) ◽  
pp. 271-286 ◽  
Author(s):  
Nicolas Palanca-Castan ◽  
Christine Köppl
Keyword(s):  
Delay Line ◽  
Low Frequency ◽  
Barn Owl ◽  
Divergent Evolution ◽  
Medial Superior Olive ◽  
Data Set ◽  
Line Model ◽  
Nucleus Laminaris ◽  
Interaural Level Differences

Localization of sound sources relies on 2 main binaural cues: interaural time differences (ITD) and interaural level differences. ITD computing is first carried out in tonotopically organized areas of the brainstem nucleus laminaris (NL) in birds and the medial superior olive (MSO) in mammals. The specific way in which ITD are derived was long assumed to conform to a delay line model in which arrays of systematically arranged cells create a representation of auditory space, with different cells responding maximally to specific ITD. This model conforms in many details to the particular case of the high-frequency regions (above 3 kHz) in the barn owl NL. However, data from recent studies in mammals are not consistent with a delay line model. A new model has been suggested in which neurons are not topographically arranged with respect to ITD and coding occurs through assessment of the overall response of 2 large neuron populations - 1 in each brainstem hemisphere. Currently available data comprise mainly low-frequency (<1,500 Hz) recordings in the case of mammals and higher-frequency recordings in the case of birds. This makes it impossible to distinguish between group-related adaptations and frequency-related adaptations. Here we report the first comprehensive data set from low-frequency NL in the barn owl and compare it to data from other avian and mammalian studies. Our data are consistent with a delay line model, so differences between ITD processing systems are more likely to have originated through divergent evolution of different vertebrate groups.

scholarly journals Variability Reduction in Interaural Time Difference Tuning in the Barn Owl

2008 ◽  
Vol 100 (2) ◽  
pp. 708-715 ◽  
Author(s):  
Brian J. Fischer ◽  
Masakazu Konishi
Keyword(s):  
Anterior Part ◽  
Interaural Time Difference ◽  
Barn Owl ◽  
Time Difference ◽  
Central Nucleus ◽  
Nucleus Laminaris ◽  
Cochlear Nuclei ◽  
Reduction Property ◽  
Single Burst ◽  
Barn Owls

The interaural time difference (ITD) is the primary auditory cue used by the barn owl for localization in the horizontal direction. ITD is initially computed by circuits consisting of axonal delay lines from one of the cochlear nuclei and coincidence detector neurons in the nucleus laminaris (NL). NL projects directly to the anterior part of the dorsal lateral lemniscal nucleus (LLDa), and this area projects to the core of the central nucleus of the inferior colliculus (ICcc) in the midbrain. To show the selectivity of an NL neuron for ITD requires averaging of responses over several stimulus presentations for each ITD. In contrast, ICcc neurons detect their preferred ITD in a single burst of stimulus. We recorded extracellularly the responses of LLDa neurons to ITD in anesthetized barn owls and show that this ability is already present in LLDa, raising the possibility that ICcc inherits its noise reduction property from LLDa.

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