background: spinal muscular atrophy (sma) is the second most common lethal autosomal recessive disease. it is a neuromuscular disorder caused by degenerative of lower motor neurons and occasionally bulbar neurons leading to progressive limb paralysis and muscular atrophy. the smn1 gene is recognized as a sma causing gene while naip has been characterized as a modifying factor for the clinical s...

The Dual Role of Notch Signaling During Motor Neuron Differentiation Glenn Christopher Tan Throughout the developing spinal cord, Olig2 progenitors in the motor neuron progenitor domain give rise to an impressive array of motor neurons, oligodendrocytes and astrocytes. Motor neurons are further diversified into motor columns and pools based on cell body settling position, general axonal traject...

Spinal muscular atrophy, a common autosomal recessive motor neuron disorder, is caused by the loss of the survival motor neuron gene (SMN1). SMN2, a nearly identical copy gene, is present in all spinal muscular atrophy patients but differs by a critical nucleotide that alters exon 7 splicing efficiency. This results in low survival motor neuron protein levels, which are not enough to sustain mo...

Sensory-motor circuits in the spinal cord are constructed with a fine specificity that coordinates motor behavior, but the mechanisms that direct sensory connections with their motor neuron partners remain unclear. The dorsoventral settling position of motor pools in the spinal cord is known to match the distal-to-proximal position of their muscle targets in the limb, but the significance of in...

The orbicularis oris and buccinator muscles of mammals form an important subset of the facial musculature, the perioral muscles. In many taxa, these muscles form a robust muscular hydrostat capable of highly manipulative fine motor movements, likely accompanied by a specialized pattern of innervation. We conducted a retrograde nerve-tracing study of cranial nerve (CN) VII in pigs (Sus scrofa) t...