The Journal of Neuroscience, December 15, 1999, 19(24):10908-10922
Corticostriatal Projections from Rat Barrel Cortex Have an
Anisotropic Organization that Correlates with Vibrissal Whisking
Behavior
Kevin D.
Alloway,
Jennifer
Crist,
Joshua J.
Mutic, and
Stephane A.
Roy
Department of Neuroscience and Anatomy, Penn State University
College of Medicine, Hershey, Pennsylvania 17033-2255
To elucidate the detailed organization of corticostriatal
projections from rodent somatosensory cortex, the anterograde tracers biotinylated dextran amine (BDA) and fluoro-ruby (FR) were injected into separate parts of the whisker "barrel" representation. In one
group of rats, the two tracers were injected into different barrel
columns residing in the same row; in the other group of rats, the
tracers were deposited into barrel columns residing in different rows.
Reconstructions of labeled axonal varicosities in the neostriatum and
ventrobasal thalamus were analyzed quantitatively to compare the extent
of overlapping projections to these subcortical structures. For both
groups of animals, corticostriatal projections terminated in densely
packed clusters that occupied curved lamellar-shaped regions along the
dorsolateral edge of the neostriatum. When the tracers were injected
into different whisker barrel rows, the distribution of BDA- and
FR-labeled terminals in the neostriatum followed a crude somatotopic
organization in which the amount of overlap was approximately the same
as in the ventrobasal thalamus. When both tracers were injected into
the same whisker barrel row, however, the amount of corticostriatal
overlap was significantly higher than the amount of overlap observed in
the ventrobasal thalamus. These results indicate that
corticostriatal projections from whisker barrel cortex have an
anisotropic organization that correlates with the pattern of vibrissal
movements during whisking behavior.
Key words:
anterograde tracing; axonal varicosities; convergence; divergence; neostriatum; pattern recognition; somatosensory cortex; ventrobasal thalamus
Copyright © 1999 Society for Neuroscience 0270-6474/99/192410908-15$05.00/0