Trigeminal nerve and eating in the pigeon (Columba livia): neurosensory control of the consummatory responses.

Electrophysiological, neurobehavioral, and cinematographic techniques were used to study the role of the trigeminal nerve in the neurosensory control of eating. Analaysis of single-unit data recorded in the pigeon's trigeminal ganglion indicates that the trigeminal nerve provides somatosensory inputs from the oral region that signal the location and movement of food and monitor the extent of mouth opening. Trigeminal deafferentation, although it does not affect pecking or swallowing, severly impairs the efficiency of eating. Cinematographic analysis shows that the impairment is due to disruption of the neurosensory control of mandibulation-the process by which grain is grasped at the beak tip and moved to the back of the mouth.