The Spinobulbar System in Lamprey

Locomotor networks in the spinal cord are controlled by descending systems which in turn receive feedback signals from ascending systems about the state of the locomotor networks. In lamprey, the ascending system consists of spinobulbar neurons which convey spinal network signals to the two descending systems, the reticulospinal and vestibulospinal neurons. Previous studies showed that spinobulbar neurons consist of both ipsilaterally and contralaterally projecting cells distributed at all rostrocaudal levels of the spinal cord, though most numerous near the obex. The axons of spinobulbar neurons ascend in the ventrolateral spinal cord and brainstem to the caudal mesencephalon and within the dendritic arbors of reticulospinal and vestibulospinal neurons. Compared to mammals, the ascending system in lampreys is more direct, consisting of excitatory and inhibitory monosynaptic inputs from spinobulbar neurons to reticulospinal neurons. The spinobulbar neurons are rhythmically active during fictive locomotion, representing a wide range of timing relationships with nearby ventral root bursts including those in phase, out of phase, and active during burst transitions between opposite ventral roots. The spinobulbar neurons are not simply relay cells because they can have mutual synaptic interactions with their reticulospinal neuron targets and they can have synaptic outputs to other spinal neurons. Spinobulbar neurons not only receive locomotor inputs but also receive direct inputs from primary mechanosensory neurons. Due to the relative simplicity of the lamprey nervous system and motor control system, the spinobulbar neurons and their interactions with reticulospinal neurons may be advantageous for investigating the general organization of ascending systems in the vertebrate

Introduction to Study of Occupational Diseases of Religious

Roll 54. Commencement (Kiel). Image 8 of 36. (2 June, 1953) [PHO 1.54.9]The Boleslaus Lukaszewski (Father Luke) Photographs contain more than 28,000 images of Saint Louis University people, activities, and events between 1951 and 1970. The photographs were taken by Boleslaus Lukaszewski (Father Luke), a Jesuit priest and member of the University's Philosophy Department faculty

Larvae and pupae of New Guinea Tabanidae (Diptera) : 1. Species of Chrysops Meigen

Information on the immature stages of Australasian Tabanidae found in published literature dealt with only 17 species, all so far known only from Australia and none representing the genus Chrysops Meigen. Two of the four Australasian species of Chrysops are found on the island of New Guinea, and both, C. albicinctus Wulp and C. australis Ricardo, are described and illustrated