Auditory frequency-following response: neural or artifact?

An electrical response which reproduces the waveform and frequency of the sound stimulus can be recorded from the central neural pathway for audition. Controversy has existed for some years over whether this frequency-following response (FFR) is neural or an artifact such as remote pickup of the cochlear microphonic or cross talk in the recording system. Two experiments resolve this issue by demonstrating that the frequency-following response depends upon functionally intact neural pathways. The frequency-following response, as well as auditory evoked potentials, is abolished by section of the eighth nerve; it is reversibly abolished by cooling of the cochlear nucleus.

Acccumulation of labeled zinc, strontium, and calcium in bone injuries

A significantly increased uptake of 65Zn administered intravenously was detected in healing bones of rats compared with control rats. The parameters used for measuring osteogenesis included: histologic examination, radiographic studies, and Ca 45 uptake in bone. The accumulation of 65Zn appeared to be correlated with bone formation. The data suggest a mobilization of zinc to the site of bone repair.

Pneumatosis cystoides intestinalis

A brief outline of the aetiology and pathogenesis of pneumatosis cystoides intestinalis is given followed by a review of four cases which have occurred in the Glasgow area recently. The radiological appearances of the condition are considered in detail.