Collateral projection from the locus coeruleus to whisker-related sensory and motor brain regions of the rat

• Published in: Journal of comparative neurology (1911) Vol. 514; no. 4; pp. 387 - 402
• Main Authors: Lee, Sat-Byol, Beak, Suk K., Park, Seung H., Waterhouse, Barry D., Lee, Hyun S.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.06.2009
• Subjects: Analysis of Variance; Animals; Dopamine beta-Hydroxylase - metabolism; Female; Gold Colloid; Immunohistochemistry; locus coeruleus; Locus Coeruleus - anatomy & histology; Locus Coeruleus - metabolism; Male; Motor Cortex - anatomy & histology; Neural Pathways - anatomy & histology; Neurons - metabolism; Rats; Rats, Sprague-Dawley; sensorimotor integration; Somatosensory Cortex - anatomy & histology; Thalamic Nuclei - anatomy & histology; tract tracing; Trigeminal Nuclei - anatomy & histology; Vibrissae; Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate
• ISSN: 0021-9967; 1096-9861
• DOI: 10.1002/cne.22012

The primary goal of this study was to examine whether the locus coeruleus (LC) provides collateral projections to whisker‐related, sensorimotor brain regions. After injections of retrograde tracers into the primary sensory (S1) barrel field/primary whisker motor (M1) cortices, ventroposteromedial (VPM)/ventrolateral (VL) thalamic nuclei, or principal sensory trigeminal (Pr5)/facial motor (Mo7) nuclei, the distribution of double‐labeled neurons within the LC was examined. Our observations indicated that a large number of individual LC cells provided axon collaterals to S1‐M1 or VPM‐VL regions, whereas only a few projected to Pr5‐Mo7 nuclei. The laterality and the distribution of dual‐projecting LC neurons were as follows. 1) The neurons projecting to the S1‐M1 cortices were predominantly ipsilateral (96% ± 0.7%). Labeled neurons were located ventrally at the rostral pole but were evenly distributed along the dorsoventral aspect of the principal LC. 2) The cells projecting to the VPM‐VL nuclei were bilateral, with ipsilateral (68% ± 2.3%) dominance. Neurons were observed at the rostrocaudal extent of the LC, where the labeling was most pronounced at the ventral, principal LC. 3) The neurons projecting to the Pr5‐Mo7 regions exhibited slightly contralateral (56% ± 2.9%) dominance, where labeled cells were confined within the ventral margin of the principal subdivision. Taken together, the present observations demonstrate that each subdivision of the LC possesses a differential functional organization with respect to its collateral projection to whisker‐related sensorimotor targets, suggesting that the nucleus might play a modulatory role in vibrissal sensorimotor integration that allows the guidance of behavioral action essential for the survival of the animal. J. Comp. Neurol. 514:387–402, 2009. © 2009 Wiley‐Liss, Inc.