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Widespread Horizontal Connections Arising from Layer 5/6 Border Inverted Cells in Rabbit Visual Cortex
Author(s) -
Reblet Conceptión,
LópezMedina Antonio,
GómezUrquijo Sonia M.,
BuenoLópez José L.
Publication year - 1992
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.1992.tb00870.x
Subject(s) - axoplasmic transport , visual cortex , striate cortex , cortex (anatomy) , horseradish peroxidase , anatomy , neuroscience , border cells , orientation column , chemistry , biology , biophysics , physics , cell , nuclear magnetic resonance , biochemistry , enzyme
Herein we describe the inverted cells [defined as those projection neurons having a major dendritic shaft abpially oriented (Bueno‐López et al., Eur. J. Neurosci. , 3, 415, 1991)] originating a unique set of cortical connections characterized by extraordinarily widespread horizontal distribution. Single and multiple injections of wheatgerm agglutinin ‐ horseradish peroxidase were made in areas 17 and 18 and the resulting retrograde labelling in the cortex was analysed. The findings were assessed in independent control experiments in which Fluoro‐Gold was used as retrograde tracer. Following single injections in area 17 several separate patches of labelled cells comprising layers 2–6 were consistently found in area 18. In addition to these associational cells a number of labelled cells appeared at the layer 5/6 border but were distributed over most of the tangential extent of the visual occipital cortex. This widespread pattern was particularly striking in brains after multiple injections. In these brains a conspicuous band of labelled cells at the 5/6 border radiated from the injection sites, making up an apparently continuous horizontal sheet that intersected the striate ‐ extrastriate boundary and merged with the patches of labelled cells in area 18 and beyond. Most of the cells in the 5/6 border band were inverted cells (82%; n = 2081). Injections in area 18 failed to produce such a widespread set of labelled cells in area 17. The functional significance of these connections furnished by the 5/6 border inverted cells remains to be determined, but their distribution would allow for convergent/divergent binding interactions both intra‐areally (within area 17) and inter‐areally (from area 18 to area 17).