Intrinsic inhibitory pathways in mouse barrel cortex.
The organization of intrinsic connections in the mouse somatosensory cortex was studied by combining tract-tracing and immunocytochemical techniques. Injections of HRP or fluorescent beads were made into the supragranular or infragranular layers of the posteriomedial barrel subfield. Numerous cells were retrogradely labeled within a vertical column centered on each injection site. Retrogradely labeled cells were also found > 3 mm horizontal to the injection. Dual-label immunocytochemistry identified the population of inhibitory, GABAergic cells forming intrinsic horizontal connections. Double-labeled cells were found predominantly within a 200 microns radius horizontal to an injection site. These findings indicate that intrinsic inhibitory pathways in the barrel cortex do not provide a substrate for direct GABAergic interactions among barrel columns, and that inter-columnar interactions are primarily excitatory.
Aroniadou-Anderjaska
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Department of Anatomy, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
Keller
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D000818:Animals; D001370:Axonal Transport; D001931:Brain Mapping; D005456:Fluorescent Dyes; D006735:Horseradish Peroxidase; D008297:Male; D051379:Mice; D008863:Microspheres; D013003:Somatosensory Cortex / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000502:physiology
D005456:Fluorescent Dyes; D005680:gamma-Aminobutyric Acid; D006735:Horseradish Peroxidase