Faculty Bibliography

1. Isolated, unstimulated abdominal ventral nerve cords of Limulus display patterns of motor output characteristic of rhythmic gill ventilation and of gill cleaning (Fig. 2). 2. The motor output may occur as long-term patterns of alternate gill cleaning and ventilation (Fig. 3), or alternate gill cleaning and tonic activity (Fig. 4). 3. Two patterns of gill cleaning motor output, apparently corresponding to the left-leading and right-leading patterns observed in intact animals, persist in the isolated ventral cord (Fig. 4). These two patterns occur with the same rough alternation as in intact animals. 4. Thus all the patterns of gill-plate movement in intact animals, except those involving swimming, have underlying motor programs that are expressed in isolated nerve cords in the absence of stimulation or of sensory feedback. These findings extend the concept of central pattern generators to include complex and long-duration patterns of stereotyped behavior such as those underlying the movements of the Limulus abdominal appendages

Anatomical, physiological and behavioral data indicate that the auditory system matures from the periphery centrally, ie, centripetally. There is now information which shows that the developing auditory system can be modified by anatomical changes which have their greatest effect during early development. Anatomical, physiological and behavioral changes can also be brought about by the quality of the auditory stimuli which th auditory system experiences. Evidence for the plasticity of the developing auditory system has come from studies of a number of different species. The plasticity of the auditory system is of theoretical and clinical significance.

There are many different genetic syndromes in animals which result in deafness. Two major types of inherited deafness are known. The most common in animals, including man, is that in which there is early cell death of the neural epithelium. This is found in the cat, dog, mink, guinea pig, and mouse. The second type of inner ear deafness is associated with malformations of both the bony form of the inner ear and the neural epithelium. This type of deafness is that which is found in the kreisler mouse. It is also found in man, but appears to be less common than the early cell death in which there is no malformation of the bony labyrinth. This form of inherited deafness has been associated and may be secondary to genetic abnormalities of the developing CNS.

The anterior commissure technique of partial laryngectomy is useful for treating "horseshoe" lesions of the larynx. As originally described, a McNaught keel is used after the excision to maintain an open glottic chink and to prevent webbing. After three weeks, this keel is removed as a surgical procedure. During the past four years, we have treated 12 patients using 0.020-gauge Silastic sheeting to replace the McNaught keel. The Silastic sheet is anchored above and below the glottis with externally tied 2-0 proline stutures. Two to three weeks later, a direct laryngoscopy is performed and the stent is removed. This modification avoids a second surgical procedure, decreases the hospital stay, and allows for inspection of the glottis.