Gradual changes of cell size and density with distance from innervated regions in the partially deafferented lateral geniculate nucleus

Abstract

Single neurons were recorded with tungsten microelectrodes in the lateral geniculate nucleus of adult cats (LGN). Moving light bars and electrical impulses applied to the optic tract were used for stimulation. The lateral part of layer A in the contralateral LGN was chronically deafferented by photocoagulator lesions in the nasal retina. The cell properties were determined with respect to the distance of the cells from the border of normal retinal innervation. The maintained activity decreased over a distance of 200 #m accompanied by a characteristic change of interval histograms. The light-excitability decreased over the same distance, demonstrating the main role of the retinogeniculate inputs for maintained and evoked activity of LGN cells. The transmission of electrically evoked responses decreased concomitantly. But it was still possible to elicit responses in cells which were no more light-excitable. The stimulus response latencies suggested that the cells which were excitable at longer distances from the region of normal innervation belonged to the fast conducting Y type. These cells have large dendritic fields and receive retinogeniculate axons with comparatively large lateral arborizations. It is assumed that the gradually decreasing maintained activity and excitability of LGN cells with increasing distance from the remaining visual inputs in the partially deafferented LGN are due to the decreasing overlap between optic tract terminals and LGN cell dendrites. (Supported by the DFG, Ey 8).

DOI: 10.1007/BF02580824

Cite this paper

@article{Eysel2007GradualCO, title={Gradual changes of cell size and density with distance from innervated regions in the partially deafferented lateral geniculate nucleus}, author={Ulf T. Eysel and Ulf Mayer and Ulrich Wolfhard}, journal={Pfl{\"{u}gers Archiv}, year={2007}, volume={394}, pages={R62-R62} }