Modifications of behaviour associated with inherited convulsions or whirling in three strains of peromyscus

Abstract

Measures of behaviour of three strains of deermice ( Peromyscus maniculatus) which exhibit inherited types of convulsions or whirling are compared with similar measures made of a normal strain. Differences between affected and normal strains occur in the means of time taken to enter and to traverse several kinds of experimental apparatus, response time to bright light, maze learning, persistence in front of a glass barrier, and amount of spontaneous activity per unit of time. The mice of the EP strain exhibit sound-induced convulsions and also become deaf early in life. It is suggested that the inability of the adults of this strain to hear warning sounds may in part explain why they made better records than normal Peromyscus in a number of the measures. It is tentatively suggested also that a deficiency in the sense of smell leading to failure to detect warning odours may in part explain why the CV mice, which are osmogenic convulsives, made better records than normal animals for some of the measures. The tendency of the WZ mice to whirl evidently handicaps them in traversing the maze and other experimental pathways. This perhaps explains in part their poor records in some of these measures of behaviour. Their tendency to whirl may also in part explain why they respond more quickly than normal animals to the stimulus of bright light. Not all the differences between the affected and normal Peromyscus in these measures of behaviour, however, have an obvious relationship to the major defects of convulsions, deafness, defective smell, or whirling. Some of these modifications of behaviour of the abnormal strains may be due to pleiotropic effects of their major defective genes or to differences between the strains in their other genes.