Dual projections of tuberomammillary neurons to whisker-related, sensory and motor regions of the rat

• Published in: Brain research Vol. 1354; pp. 64 - 73
• Main Authors: Hong, Eun Y, Beak, Suk K, Lee, Hyun S
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2010; Elsevier
• Subjects: Animals; Axon collaterals; Biological and medical sciences; Cell Count; Female; Fundamental and applied biological sciences. Psychology; Hypothalamic Area, Lateral - physiology; Immunohistochemistry; Male; Motor Cortex - physiology; Neural Pathways - physiology; Neurology; Neuronal Tract-Tracers; Neurons - physiology; Rats; Rats, Sprague-Dawley; Sensorimotor integration; Silver Staining; Somatosensory Cortex - physiology; Somesthesis and somesthetic pathways (proprioception, exteroception, nociception); interoception; electrolocation. Sensory receptors; Tract tracing; Trigeminal Nuclei - physiology; Tuberomammillary nucleus; Vertebrates: nervous system and sense organs; Vibrissae; Vibrissae - physiology; Sensorimotor integration; Vibrissae; Tract tracing; Tuberomammillary nucleus; Rat; Rodentia; Central nervous system; Projection; Encephalon; Vertebrata; Sensorimotor coordination; Mammalia; Neuron; Animal; Sensorimotor cortex; Vibrissa
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2010.07.093

Abstract The primary goal of this study was to examine in the rat whether neurons in the tuberomammillary nucleus (TMN) provide axon collaterals to whisker-related, sensorimotor regions at cortical and brainstem levels, using two different retrograde tracers. When injections were made at primary sensory (S1) barrel field/primary whisker motor (M1) cortices, dual-projecting TMN neurons were observed mainly in the ventrolateral subdivision; the projection was almost exclusively ipsilateral. On the other hand, following injections of tracers into whisker-related, principal sensory trigeminal (Pr5)/lateral facial motor (Mo7) nuclei, dual-projecting cells were observed mainly in the dorsomedial subdivision; the projection was bilateral with a slight contralateral dominance. Taken together, the present observation demonstrated that each subdivision of the TMN possessed a differential functional organization with respect to its collateral projection to whisker-related sensorimotor targets, suggesting that the histaminergic projection might play a modulatory role in vibrissal sensorimotor integration, which allows the guidance of behavioral action essential for the survival of the animal.