Hippocampal auditory gating in the hyperactive mocha mouse

The mouse mutants mocha (mh) and mocha(2J) (mh(2J)) result from separate mutations 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 function of the hippocampus. Depth electrode recordings of hippocampal auditory evoked potentials revealed that the response to the first of two paired tones was significantly enhanced in mocha and moch(2J), as compared with littermate controls. The pronounced theta rhythm characteristic of unanesthetized mocha mice was not observed in these chloral-hydrate anesthetized mice, whereas spike discharge activity was frequently present in the recordings. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.