CHARACTERIZATION OF NEURONAL RESPONSES IN THE ZONA INCERTA OF THE SUBTHALAMIC REGION OF THE SHEEP DURING INGESTION OF FOOD AND LIQUID

Single-unit recordings were made from the zona incerta of the subthalamic region of conscious sheep during ingestion. Some cells responded to ingestion and not to associated chewing, arousal or odour stimuli. Most cells changed their activity shortly after food entered the mouth and throughout ingestion, but a few responded immediately food entered the mouth and not during the remaining period of ingestion. Most cells responded to ingestion of solids but not liquids, and preferred foods often evoked the greatest changes in firing rate. Other cells respondedqually to ingestion of solids and liquids or to a single substance. A number of cells responded to chewing and had significantly higher firing rates and shorter action potentials than those responding to ingestion.