Martina Manns

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Functional cerebral asymmetries, once thought to be exclusively human, are now accepted to be a widespread principle of brain organization in vertebrates [1]. The prevalence of lateralization makes it likely that it has some major advantage. Until now, however, conclusive evidence has been lacking. To analyze the relation between the extent of cerebral(More)
One-day-old pigeons (Columba livia) were monocularly deprived by occluding the left or the right eye for 10 days. Up to 3 years later, degree and direction of functional and morphological asymmetries of deprived and control pigeons were analyzed. In control pigeons, the usual right-eye superiority was obtained in a visual discrimination task. In left-eye(More)
The avian isthmic nuclei are constituted by a group of structures reciprocally connected with the tectum opticum and considered to play a role in the modulation of intratectal processes. Although the two larger isthmic nuclei, the n. isthmi pars parvocellularis (Ipc) and the n. isthmi pars magnocellularis (Imc), have been studied in detail previously, the(More)
Tetrodotoxin is one of the most potent and oldest known neurotoxins. It acts by blocking the voltage-gated sodium channels in nerve cell membranes, leading to a transient silencing of neural activity. TTX is among the most widely used pharmacological agents for the temporary and selective blocking of neural structures. As such, an exact knowledge of the(More)
The dominance for visual pattern analysis of the left hemisphere in normal pigeons and the concomitant morphological asymmetries in the optic tectum can be attributed to a 'natural' prehatch monocular deprivation of the left eye resulting from an asymmetrical embryonic position within the egg. Using control animals and pigeons which were monocularly(More)
The optic tectum of vertebrates is an essential relay station for visuomotor behavior and is characterized by a set of connections that comprises topographically ordered input from the eyes and an output that reaches premotor hindbrain regions. In the avian tectofugal system, different ascending cell classes have recently been identified based on their(More)
A large body of evidence indicates that pigeons use olfactory cues to navigate over unfamiliar areas with a differential contribution of the left and right hemispheres. In particular, the right nostril/olfactory bulb (OB) and left piriform cortex (Cpi) have been demonstrated to be crucially involved in navigation. In this study we analysed behaviour-induced(More)
The vertebrate nervous system has been shown to contain high concentrations of intracellular calcium-binding proteins, each of them with a restricted expression pattern in specific brain regions and specific neuronal subpopulations. Using immunohistochemical staining techniques, we analyzed the expression pattern of calbindin, calretinin and parvalbumin in(More)
The magnetic compass of migratory birds has been suggested to be light-dependent. Retinal cryptochrome-expressing neurons and a forebrain region, "Cluster N", show high neuronal activity when night-migratory songbirds perform magnetic compass orientation. By combining neuronal tracing with behavioral experiments leading to sensory-driven gene expression of(More)
The formation of functional and morphological asymmetries within the pigeon's tectofugal system depends on left-right differences in visual input during embryonic development. This asymmetric stimulation presumably affects activity-dependent differentiation processes within the optic tectum. Behavioral studies reveal that prehatch light stimulation(More)