System organization of alimentary behavior in the newborn and the developing cat

This review deals with the structural, behavioral, and EEG correlates of searching for food and food intake. Data were collected on freely behaving kittens of 1 to 60 days of age with chronically implanted electrodes. The 1st manifestations of hunger involve activation of limbic-reticular structures and electroencephalographic (EEG) activity consisting of fast oscillations of 30-40-60 cps, correlated with general behavioral arousal as manifested by motor restlessness and vocal reactions. The more specific behavior form of hunger--feeding motivation--involves structures that include the motor and parietal cortex, amygdala, and medial hypothalamus; the EEG activity consists of high-amplitude, slow waves of 3-6 or 6-8 cps; and the behavioral correlate is purposeful search for the mother's teat or food. Satiation is associated with activity of the synchronizing structures in the forebrain and lower brain stem, as well as in the relay nuclei that transmit the sensory flow from oral afferents; EEG activity consists of regular rhythms of 10-14 and 2-4 cps; and the behavioral correlate is the act of feeding.