Drinking: Hindbrain Sensorimotor Neural Organization

Numerous studies suggest that the patterned motor responses of drinking and swallowing are organized at the brainstem level (reviewed in Berntson and Micco 1976). Decerebration experiments further indicate that tactile and gustatory receptors can modify fluid intake using brainstem mechanisms, but that drinking to correct a water imbalance and spontaneous drinking both require an intact forebrain (Grill and Miselis 1981). Because only a fraction of an animal’s behaviour is evident when the forebrain and hindbrain are disconnected, decerebrate preparations provide an experimental method for establishing a gross anatomical location for function. Careful behavioural testing reveals those sensory and motor capacities that are intact, thereby allowing anatomical and physiological studies to be interpreted within the context of a limited, but specific, behavioural repertoire. The first section of this chapter reviews the sensorimotor capacity of the decerebrate preparation with respect to ingestive behaviour. This is followed by several sections discussing brainstem pathways mediating these responses.