Hippocampal auditory gating in the hyperactive mocha mouse

The mouse mutants mocha (mh) and mocha(2J) (mh(2J)) result from separate mu tations in the same gene (AP-3 delta) that arose independently on different backgrounds of inbred strains. They exhibit a neurological phenotype that includes hyperactivity, an epileptiform EEG and changes in the basic functi on of the hippocampus. Depth electrode recordings of hippocampal auditory e voked potentials revealed that the response to the first of two paired tone s was significantly enhanced in mocha and moch(2J), as compared with litter mate controls. The pronounced theta rhythm characteristic of unanesthetized mocha mice was not observed in these chloral-hydrate anesthetized mice, wh ereas spike discharge activity was frequently present in the recordings. (C ) 1999 Elsevier Science Ireland Ltd. All rights reserved.