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Retinal cells have been induced to project into the medial geniculate nucleus, the principal auditory thalamic nucleus, in newborn ferrets by reduction of targets of retinal axons in one hemisphere and creation of alternative terminal space for these fibers in the auditory thalamus. Many cells in the medial geniculate nucleus are then visually driven, have(More)
How does cortex that normally processes inputs from one sensory modality respond when provided with input from a different modality? We have addressed such a question with an experimental preparation in which retinal input is routed to the auditory pathway in ferrets. Following neonatal surgical manipulations, a specific population of retinal ganglion cells(More)
We have previously reported that following specific neonatal brain lesions in ferrets, a retinal projection is induced into the auditory thalamus (Sur et al., Science 242:1437, '88). In these "rewired" ferrets, a novel visual pathway is established through auditory thalamus [the medial geniculate nucleus (MGN)] and primary auditory cortex (A1); cells in(More)
The organization of cortical circuitry responsible for processing sensory information is a subject of intense examination. However, it is not known whether cortical cells in different sensory cortices process information in a way that is specific to the modality of their input, or whether there are commonalities in processing circuitry across different(More)
Early developmental manipulations can induce sensory afferents of one modality to project to central targets of a different sensory modality. We and other investigators have used such cross-modal plasticity to examine the role of afferent inputs and their patterns of activity in the development of sensory neocortex. We suggest that the afferent rewiring can(More)
Maps of sensory surfaces are a fundamental feature of sensory cortical areas of the brain. The relative roles of afferents and targets in forming neocortical maps in higher mammals can be examined in ferrets in which retinal inputs are directed into the auditory pathway. In these animals, the primary auditory cortex contains a systematic representation of(More)
The mammalian lateral geniculate nucleus (LGN) is known to regulate signal transfer from the retina to the brain neocortex in a highly complex manner. Besides inputs from the brainstem, extraretinal inputs via corticogeniculate projections and local inhibitory neurons modulate signal transfer in the LGN. However, very little is known about whether the(More)
Monocular enucleation at E36, followed by intracellular labeling of single, physiologically identified X and Y axons, demonstrates fundamental differences in their termination patterns within the lateral geniculate nucleus (LGN). X axons have arbors that appear normal in their dorsoventral extent, though some are located in inappropriate regions of the LGN.(More)
The lateral geniculate nucleus of the ferret contains not only eye-specific layers, but a further subdivision of layers A and A1 into inner and outer sublaminae that contain, respectively, ON-center and OFF-center cells (Stryker and Zahs, '83). To study how the arbors of single retinal ganglion cell axons correlate with these cellular divisions, we have(More)
The autoradiographic analysis of neurotransmitter receptor distribution is a powerful technique that provides extensive information on the localization of neurotransmitter systems. Computer methodologies are described for the analysis of autoradiographic material which include quench correction, 3-dimensional display, and quantification based on anatomical(More)