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We have examined the patterns of termination of single, physiologically identified optic tract fibers in the dorsal lateral geniculate nucleus (LGNd) of the cat. The axons were impaled with a recording micropipette and characterized by their responses to light and by their conduction latencies to electrical stimulation of the optic nerve. Horseradish(More)
During animal development, the HOM-C/HOX proteins direct axial patterning by regulating region-specific expression of downstream target genes. Though much is known about these pathways, significant questions remain regarding the mechanisms of specific target gene recognition and regulation, and the role of co-factors. From our studies of the gnathal and(More)
1. Recordings were made from single axons of 218 ganglion cells in the optic nerve of the turtle, Pseudemys scripta elegans. Responses to light stimuli were used to classify 182 of the cells into four functional groups.2. Movement-sensitive cells (113 units) responded best to moving stimuli independent of the stimulus colour or direction of motion. Their(More)
Because the axons of retinal ganglion cells are the sole channels carrying information from the eye, the organization of their central projections is important in visual processing. However, their detailed destinations and patterns of synaptic distribution at the level of single, functionally identified cells are not known. Most anatomical studies involve(More)
Experiments on the lateral geniculate nucleus (LGN) of the cat based on 14C 2-deoxyglucose (2-DG) autoradiography and intraocular injections of 2-amino-4-phosphonobutyric acid (APB) provided evidence for gradients of metabolic activity in the ON and OFF pathways in layer A, but only very weakly, if at all, in layer A1. Alert and freely moving cats were(More)
The hypothesis was tested that ON and OFF cells in the A layers of the cat's lateral geniculate nucleus (l.g.n.) form separate ON and OFF columns, and new evidence for their sublaminar distributions is presented. Evidence for columns was sought in previously published results from 184 electrode tracks oriented parallel to the layers and in new experiments,(More)
Responses to light were recorded extracellularly from single cells in the A laminae of the dorsal lateral geniculate nucleus (d.l.g.n.) in the cat. Micro-electrodes were passed through the nucleus parallel to the laminar borders allowing the depths of the cells to be measured accurately and the depth distributions of the different cell types to be(More)
Using two microelectrodes, recordings were made from pairs of like-signed cells at different depths in single layers (A or A1) of the cat's lateral geniculate nucleus (LGN). The cells were chosen to have near or overlapping receptive fields so that they could be stimulated simultaneously with a single spot or bar of light. Under these controlled conditions,(More)
A novel technique for retrograde labelling was used to trace the axonal projections from the lateral geniculate nucleus (LGN) to the striate cortex in the cat. Cortical deposits of horseradish peroxidase were made in the form of long straight lines oblique to layer IV. The projections along the lengths of these linear deposits were inferred, by retinotopic(More)
1. Extracellular recordings were made from 131 X-like cells (hereafter called X cells) at different depths in layer A of the lateral geniculate nucleus (l.g.n.) in the cat. The depths of the cells were measured accurately by orienting the electrodes parallel to the borders of the layer and reconstructing the electrode tracks from histological sections. 2.(More)