Fluorescent dye injected into the body cavity of loco^Δ13 embryos penetrates into the nerve cord after the stage at which the nerve cord is sealed in wild-type embryos, showing the formation of the blood-brain barrier is defective. Although the normal complement of surface glia is found at the surface of the nerve cord in loco^Δ13 mutants, these glia show a number of defects. They are irregular in size and shape with a disrupted cortical cytoskeleton at the cell cortex and variably-positioned nuclei. Additionally, the septate junctions are significantly shorter in length and less organized than in wild-type glia.

When loco^Δ13 or loco^Δ293 are trans with loco^M1 at 25^oC escapers are produced. Escapers show a paralytic phenotype, and drop into the food and die of not rescued. Rescued adults show a severe impairment of spontaneous locomotor activity and show a shaking phenotype. Response to mechanical stimulation is weak (for loco^Δ293) and non-existent (for loco^Δ13). All adult escapers die after a maximum of 2 days. Examination of embryos reveals a slight defasciculation of axons, and occasional crossing within the longitudinal connectives. No major defects are evident in glial cell number or position but the perineurial glia sheath is virtually absent. Glial-glial cell contact is severely disrupted.