The specificity of innervation of regenerating motor neurons in the cockroach.

The pattern of neuromuscular connections of cockroach motor neurons regenerating to an intact mesothoracic leg after crushing nerve 5 has been investigated. While a number of anatomically identified motor neurons reestablished functional connections with their correct target muscles, some of the same and other motor neurons were found to functionally innervate inappropriate muscles. Muscles, and in some cases individual fibres, were often simultaneously innervated by both correct and foreign motor neurons. The frequency of innervation errors decreased with increasing post-operative times, although some errors persisted to the latest stages examined (227 days).