Tectoreticular pathways in the turtle, <i>Pseudemys scripta</i>. I. Morphology of tectoreticular axons

Sereno, Martin I.; Ulinski, Philip S.

doi:10.1002/cne.902330105

Cited by 41 publications

(39 citation statements)

References 57 publications

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“…The present results also showed strong qualitative similarities between target areas of tectal efferents in teleosts compared with other species of elasmobranchs (Ebbesson, 1972;Smeets, 1981), amphibians, (Lázá r, 1969Masino and Grobstein, 1990), reptiles (Ulinski, 1977;Sereno, 1985), avians (Hunt and Kü nzle, 1976;Masino and Knudsen, 1992), and even mammals (Graham, 1977;Harting, 1977;Grantyn and Grantyn, 1982;Huerta and Harting, 1982;Redgrave et al, 1987a;Cowie and Holstege, 1992). This suggests that the functional properties of the tectum maintain a quite conservative structural pattern of connectivity with regions of the brainstem across vertebrates.…”

Section: General Considerationssupporting

confidence: 65%

Influence of the tectal zone on the distribution of synaptic boutons in the brainstem of goldfish

1998

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This study investigated whether the topographic differences in the functional properties of the tectal motor map of goldfish are related to particular patterns of connections with downstream structures. With this aim, the distribution of synaptic boutons in the mesencephalic and rhombencephalic structures was studied after discrete injections of the tracer biotinylated dextran amine were placed at separate sites along the tectal anteroposterior axis. Irrespective of the location of the injection site, the boutons were more abundant in the mesencephalon than in the rhombencephalon, and they were located chiefly ipsilaterally all throughout the brainstem. In the mesencephalon, the boutons were found in its ventrolateral reticular formation and, to a lesser extent, in the nucleus of the medial longitudinal fasciculus, the oculomotor and isthmi nuclei, and the torus semicircularis. In the mesencephalic reticular formation, the bouton location was distributed topographically with respect to the injection site. Terminals were also observed in the nucleus of the medial longitudinal fasciculus after injections into anteromedial or middle tectal zones. In the oculomotor nucleus, boutons were present exclusively in the case of the anteromedial injection. In the rhombencephalon, most boutons were found in the superior reticular formation, and their number decreased in the medial and inferior reticular formations. A topographic distribution could be observed within the superior reticular formation, although its density was attenuated compared with that observed in the mesencephalic reticular formation. The domains of synaptic endings on the ipsilateral side were different from those on the contralateral side: The ipsilateral synaptic endings were located more medially. Finally, a few boutons were also found in the vestibulocerebellar area on either the ipsilateral or the contralateral side, depending on the injection site. From these data, the authors conclude that, in goldfish, irrespective of the tectal injection site, the endings are in similar nuclei in the brainstem; however, the distribution of synaptic boutons within such nuclei can be related to the functional properties of each tectal zone.

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Section: General Considerationssupporting

confidence: 65%

Influence of the tectal zone on the distribution of synaptic boutons in the brainstem of goldfish

1998

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“…The brain was postfixed overnight at 4°C, sectioned in cold pH 7.2 phosphate buffer with a vibratome, and allowed to react with diaminobenzidine as a chromagen. Several of the best-labeled fibers were reconstructed in each case by the method of Sereno (13). The tonotopic organization of the nucleus magnocellularis resulted in labeled fibers traveling together.…”

Section: Methodsmentioning

confidence: 99%

Axonal delay lines for time measurement in the owl's brainstem.

Carr

Konishi²

1988

Proc. Natl. Acad. Sci. U.S.A.

288

144

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Interaural time difference is an important cue for sound localization. In the barn owl (Tyto alba) neuronal sensitivity to this disparity originates in the brainstem nucleus laminaris, Afferents from the ipsilateral and contralateral magnocellular cochlear nuclei enter the nucleus laminaris through its dorsal and ventral surfaces, respectively, and interdigitate in the nucleus. Intracellular recordings from these afferents show orderly changes in conduction delay with depth in the nucleus. These changes are comparable to the range of interaural time differences available to the owl. Thus, these afferent axons act as delay lines and provide anatomical and physiological bases for a neuronal map of interaural time differences in the nucleus laminaris.Jeffress (1) proposed a model, the place theory, for measurement of the interaural time differences that underlie sound localization. His theory contained two important concepts, the first being the principles of delay lines and coincidence detection. The second states that the "place" or anatomical location of the neuron in an array encodes the place or location of the sound. In the model, the coincidence detectors are binaural neurons which require simultaneous arrival of spikes from the two sides to elicit a maximal discharge. Signals reach these coincidence detectors by axonal paths which are unequal for the two sides. This difference in path lengths translates into a disparity in spike conduction time. The coincidence detectors respond preferentially to an interaural time difference that delays the arrival of spikes on the shorter path, and advances the arrival of spikes on the longer path so as to cause the spikes to arrive simultaneously. Subsequently, several authors proposed cross-correlation models of sound localization using the same principles (2, 3). Goldberg and Brown (4), working on the superior olive ofdogs, obtained data consistent with the Jeffress model, and similar results have been obtained in cats (5).Barn owls use interaural time differences to localize sound in azimuth (6). Neuronal sensitivity to these time differences arises in the nucleus laminaris (7), the avian homologue of the medial superior olive. As in the superior olive, physiological responses from nucleus laminaris are consistent with the principles of the Jeffress model (8).Despite the widespread acceptance of the Jeffress model, the nature of the delay lines and the cellular mechanisms of coincidence detection remain to be investigated. Conduction delays can be produced by several different methods, such as variation in membrane time constants, number of synapses, length of dendrites, and length of axonal path (9, 10). We present both anatomical and physiological evidence for axonal delay lines in the barn owl's nucleus laminaris.MATERIALS AND METHODS Anatomy. Horseradish peroxidase (HRP) was used as a tracer to study the innervation of nucleus laminaris in five owls (Tyto alba) (11). Detailed protocols may be found in ref.12. Birds were anesthetized by intramuscular (i.m.)...

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“…Tectal efferent axons have been shown in cats [Grantyn and Grantyn, 1982], turtles [Sereno, 1985] and snakes [Dacey and Ulinski. 1986] to be highly branched and diffuse in their projections to tegmental target nuclei.…”

Section: Tecto-reticulo-spinal Circuits Underlying Orienting Movementsmentioning

confidence: 99%

Brainstem Control of Orienting Movements: Intrinsic Coordinate Systems and Underlying Circuitry

Masino¹

1992

Brain Behav Evol

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A fundamental issue in the understanding of how the nervous system processes information is the way in which sensory information is used to initiate and guide movements. Recent progress has been made by taking an information processing approach in which information - for example, the spatial location of an object towards which an animal will orient - is tracked through the nervous system from sensory to motor levels. In this approach, neurally encoded information is characterized in terms of its representation within a neural or intrinsic coordinate system or set of neural coding parameters. For example, the retina codes spatial location in terms of the location of activity on the retinal surface, whereas motoneurons code spatial location in terms of the pulling directions of the muscles they activate. In between these two peripheral stages, the information passes through intermediate coordinate systems. These intermediate coordinate systems can be characterized by recording or altering the activity of small groups of neurons while an animal is performing a well-defined sensorimotor task. Spatial location information is used to guide orienting movements, those movements made by the eyes, ears, head, or body which function to center an object of interest in the animal's visual field. The optic tectum and forebrain, their connections to the medial mesencephalic and rhombencephalic brainstem tegmental cell groups, and subsequent connections to brainstem motor nuclei and spinal cord are employed to control fundamental aspects of this behavior. Studies reviewed herein indicate that following the retinotopic coding of spatial location in the retina and tectum, spatial location information appears to enter a different coordinate system at tegmental levels in which spatial aspects of orienting movement are coded in terms of their discrete horizontal and vertical components. This Cartesian coordinate system is an example of an abstract neural coordinate system, in that it is a simple, low-dimensional representation of spatial location which differs greatly from both sensory and motor representations. Also, this Cartesian representation may be common to many orienting movements, yet it appears to differ from the coordinate systems controlling other movement types such as stabilization or phasic movements. This suggests an hypothesis in which coordinate systems, especially at intermediate levels of processing, may be organized according to behavioral task as opposed to being determined by the particular sensory or motor system involved in the behavior. Understanding the evolutionary heritage and computational function of abstract neural coordinate systems, and the relation between different coordinate systems and behavioral tasks may be useful in understanding general aspects of sensory information processing and motor control.

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Tectoreticular pathways in the turtle, Pseudemys scripta. I. Morphology of tectoreticular axons

Cited by 41 publications

References 57 publications

Influence of the tectal zone on the distribution of synaptic boutons in the brainstem of goldfish

Influence of the tectal zone on the distribution of synaptic boutons in the brainstem of goldfish

Axonal delay lines for time measurement in the owl's brainstem.

Brainstem Control of Orienting Movements: Intrinsic Coordinate Systems and Underlying Circuitry

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