Self-directed behaviour and hippocampal electrical activity in rabbits living in a semi-natural environment

Rabbits living in a semi-natural environment show a variety of behavioural elements related to voluntary or automatic movements. The aim of the present experiment was to study the hippocampal electrical correlates of self-directed activities occurring during spontaneous behaviour and emotional responses (the presence of a second rabbit of the same sex: intruder). Behaviour was divided into two broad categories. One included autocleaning elements such as scratching, shaking, washing and self-grooming. The other was characterized by consummatory activities: eating and drinking. Hippocampal activity was recorded by telemetry and the EEG periods related to specific behavioural elements were selected and analyzed. The electrical parameters were different for the various behavioural elements, for example rhythmic and irregular EEG patterns were recorded in different percentages during autocleaning and consummatory activities. Differences were also observed in the frequency peak distributions of power spectra. Confrontations influenced the occurrence of self directed behavioural elements and modified the pattern and frequency of hippocampal EEG during autocleaning activities. Results show that environmental variations can affect automatic behaviours and influence the mechanisms of hippocampal function.