Spinal afferents to lamina IX of the cervical enlargement in the rat studied by the retrograde transport of horseradish peroxidase

Abstract

Spinal neurons that project to the ventrolateral, dorsolateral and ventromedial portions of lamina IX of the cervical enlargement in the rat were investigated by means of horseradish peroxidase retrograde transport. In the cervical and upper thoracic segments, labeled neurons were observed ipsilaterally in laminae V–VIII and contralaterally in laminae VII–VIII. In the lower thoracic and upper lumbar segments, labeled neurons were seen after HRP injection into the ventrolateral part of lamina IX, and were distributed mainly in the lateral parts of the ipsilateral laminae V–VI.