Gallbladder distention and the effects of several drugs on heart rate,respiratory movements and cortical potentials in cats with hypothalamic lesions

The effects of chronic hypothalamic lesions and various drugs on the viscero-visceral reflexes of cats have been investigated, utilizing measurement of the bioelectrical activity of the cerebral cortex. After coagulation of the posterolateral hypothalamus the heart rate decreased by 40–60 beats per minute, but eventually it regained its initial value. The viscero-visceral reflexes from the gallbladder to the heart were preserved after the operative procedure. Chlorpromazine and atropine blocked both arousal and the cardiorespiratory response to stimulation of the gallbladder. Similar effects were produced by novocaine and pantocaine.     

Arousal and paired-associate learning

Walker and Tarte (1963) postulate that at short retention intervals high arousal paired-associates are reproduced more poorly than low arousal items. Walker and colleagues believe that this hypothesis is confirmed by their paired-associate learning studies. However, results of these paired-associate learning studies are position confounded artifacts. Better recall of low arousal items at short-term retention is caused by the coincidence of the recency effect and low arousal at the end of the trial. When these position effects are controlled there is no action decrement for the high arousal paired-associates. To test this assumption, the Kleinsmith and Kaplan study (1963) was replicated and two other variations were conducted. In these three studies with 76 subjects, which were tested at two minutes or 1 week, the action decrement occurs only when the two position effects coincide.