Different sets of afferents are demonstrated by the fluorescent tracers fast blue and rhodamine

Güntürkün, Onur; Melsbach, Gudrun; Hörster, Wolfgang; Daniel, Stefanie

doi:10.1016/0165-0270(93)90114-7

Cited by 41 publications

(19 citation statements)

References 22 publications

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“…As reported previously (Bischof and Niemann, 1990;Gü ntü rkü n et al, 1993;Deng and Rogers, 1996), RITC labelled retrogradely both the ipsilateral and contralateral tectal neurones after it was injected into the Rt, but TB and FG, which labelled the ipsilateral tectal neurones well, led to much less labelling of the contralateral tectal neurones after being injected into similar sites. Red beads, the same as RITC, labelled both the ipsilateral and contralateral tectal cells.…”

Section: Resultssupporting

confidence: 63%

“…In addition, red (rhodamine) beads were found to label the contralaterally projecting neurones in the tectum well, whereas green (fluorescein) beads labelled only a few of the same contralateral projections. Unfortunately, so far, there is no explanation why only rhodamine is effective in labelling the contralaterally projecting neurones in the avian tectofugal pathway (Bischof and Niemann, 1990;Gü ntü rkü n et al, 1993;Deng and Rogers, 1996). It is possible that rhodamine (free or in the form of latex beads) fluoresces more brightly and therefore can be detected even when only low levels of tracer have accumulated in the cell bodies.…”

Section: Discussionmentioning

confidence: 97%

“…Although these researchers found that there was topographical organisation of the ipsilateral tecto-Rt projections, the detailed pattern of this organisation was unclear. Furthermore, after the recent finding that a considerable number of tectal efferents project to the contralateral Rt (Bischof and Niemann, 1990;Gü ntü rkü n et al, 1993;Ngo et al, 1994), the possible topographical organisation of this contralateral projection awaits examination.…”

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confidence: 97%

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Organisation of the tectorotundal and SP/IPS‐rotundal projections in the chick

Deng

Rogers

1998

J. Comp. Neurol.

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The organisation of the neural projections from the optic tectum and pretectal nuclei complex, n. subpretectalis / n. interstitio-pretecto-subpretectalis (SP/IPS), to the nucleus rotundus (Rt) in chicks was studied by using retrograde tracing techniques. After the injection of fluorescent retrograde tracers, rhodamine-conjugated latex microspheres, fluorescein-conjugated latex microspheres, True Blue, Fluoro-Gold, or rhodamine B isothiocyanate, into different regions of Rt and its middorsal extension, the nucleus triangularis (T), the distribution of retrogradely labelled neuronal cell bodies in the tectum and pretectal nuclei was assessed. Both the ipsilateral and contralateral tectorotundal projections were found to be organised topographically in as much as different sublaminas of the stratum griseum centrale (SGC) project in an orderly manner to Rt and T. The deepest stratum of SGC overlapping into the stratum album centrale projects to T. Deep SGC projects to the dorsal Rt and superficial SGC to the ventral Rt. A band running through the centre of Rt receives input from the central sublamina of SGC, and the caudal central Rt receives input from a deeper sublamina than does the rostral central Rt. The SP/IPS projects to the ipsilateral Rt only and the projection order is dorsal SP to dorsal Rt, ventral SP to ventral Rt and middle SP to the central band of Rt. The neurones in IPS and the nucleus of the tractus tectothalamicus project to T. Thus, Rt and T receive topographically both tecto- (excitatory) and SP/IPS- (inhibitory) projections. The possible functional implications for parallel information processing in these projections are discussed.

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Section: Resultssupporting

confidence: 63%

Section: Discussionmentioning

confidence: 97%

mentioning

confidence: 97%

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Organisation of the tectorotundal and SP/IPS‐rotundal projections in the chick

Deng

Rogers

1998

J. Comp. Neurol.

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“…The small size of the hyperpallium (visual and perhaps somatosensory Wulst) in kiwi is in contrast to that reported for other nocturnal species and is unlike that of its closest relative, the emu. Nocturnal owls, such as the boobook owl (Ninox boobook) , Northern saw-whet owl (Aegolius acadicus) and barn owl (Tyto alba) , show enlargement of the visual Wulst [Iwaniuk and Hurd, 2005;Iwaniuk et al, 2008], the primary telencephalic representation of the thalamofugal system [Güntürkün et al, 1993;Shimizu and Karten, 1993]. The most extreme hypotrophy in kiwi was seen in the entopallium, the end station of the tectofugal visual pathway.…”

Section: Discussionmentioning

confidence: 99%

Morphometric Analysis of Telencephalic Structure in a Variety of Neognath and Paleognath Bird Species Reveals Regional Differences Associated with Specific Behavioral Traits

Corfield¹,

Wild²,

Parsons³

et al. 2012

Brain Behav Evol

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Birds exhibit a huge array of behavior, ecology and physiology, and occupy nearly every environment on earth, ranging from the desert outback of Australia to the tropical rain forests of Panama. Some birds have adopted a fully nocturnal lifestyle, such as the barn owl and kiwi, while others, such as the albatross, spend nearly their entire life flying over the ocean. Each species has evolved unique adaptations over millions of years to function in their respective niche. In order to increase processing power or network efficiency, many of these adaptations require enlargements and/or specializations of the brain as a whole or of specific brain regions. In this study, we examine the relative size and morphology of 9 telencephalic regions in a number of Paleognath and Neognath birds and relate the findings to differences in behavior and sensory ecology. We pay particular attention to those species that have undergone a relative enlargement of the telencephalon to determine whether this relative increase in telencephalic size is homogeneous across different brain regions or whether particular regions have become differentially enlarged. The analysis indicates that changes in the relative size of telencephalic regions are not homogeneous, with every species showing hypertrophy or hypotrophy of at least one of them. The three-dimensional structure of these regions in different species was also variable, in particular that of the mesopallium in kiwi. The findings from this study provide further evidence that the changes in relative brain size in birds reflect a process of mosaic evolution.

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“…The optic tectum displays cell size asymmetries with larger cell bodies in layers 2-12 on the left side [17], while neurons of the efferent layer 13 are enlarged on the right [5]. These efferent cells project bilaterally onto the nucleus rotundus whereby the crossed portion of this pathway is asymmetrically organized with more fibers ascending from the right optic tectum to the left nucleus rotundus than vice versa [9,10]. The higher bilateral input to the left nucleus rotundus is accompanied by larger cell bodies of rotundal relay neurons on this side [15].…”

Section: Introductionmentioning

confidence: 99%

A morphological study of the nucleus subpretectalis of the pigeon

Freund

Güntürkün

Manns

2008

Brain Research Bulletin

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In pigeons, the tectofugal system is functionally as well as structurally lateralized. So for example the right nucleus rotundus is less modulated by right forebrain influences than the left nucleus rotundus by the left ones. This functional lateralization pattern may depend on a dynamic balance between left and right tectal processing. Apart from inhibitory interactions at tectal level, suppressive influences might directly affect rotundal neurons by GABAergic input from a cluster of nuclei, the bed nuclei of the tecto-thalamic tract. A major afferent of these nuclei is the side branch of the tectorotundal projection which is of bilateral origin and which is involved in the regulation of ipsilateral as well as bilateral visual processing. Hence, an important role of the bed nuclei could be the interhemispheric communication and in turn the mediation of functional asymmetries. In a first step to unravel asymmetric influences of these nuclei, the present study investigated if the largest of the bed nuclei, the nucleus subpretectalis displays morphological asymmetries in the pigeon. We found that the nucleus subpretectalis in fact exhibits asymmetric cell sizes with larger cell bodies on the left side. This asymmetrical pattern was not present in dark-incubated animals indicating that cell size asymmetries within nucleus subpretectalis are induced by asymmetric photic stimulation during embryonic development.

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Different sets of afferents are demonstrated by the fluorescent tracers fast blue and rhodamine

Cited by 41 publications

References 22 publications

Organisation of the tectorotundal and SP/IPS‐rotundal projections in the chick

Organisation of the tectorotundal and SP/IPS‐rotundal projections in the chick

Morphometric Analysis of Telencephalic Structure in a Variety of Neognath and Paleognath Bird Species Reveals Regional Differences Associated with Specific Behavioral Traits

A morphological study of the nucleus subpretectalis of the pigeon

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