Habituation of heart rate in functionally decorticate rats.

Abstract

Habituation of acoustically evoked heart rate responses and retention of this habituation was studied in functionally decorticate rats. An improved technique to induce cortical spreading depression (CSD) resulted in a pronounced and continuous depression of electroencephalographic activity. In Experiment 1, short-term habituation (STH) was demonstrated in decorticate rats and surgical controls; long-term habituation (LTH, 24 hr) occurred only in intact animals. In Experiment 2, only CSD groups were used. As in the first experiment, STH but not LTH was obtained under CSD. However, there was clear evidence that habituation could be retained subcortically for 30 min. It is concluded that the rat's cortex is not necessary for habituation of acoustically evoked heart rate responses and retention of this habituation over a moderately long interval. However, the results suggest that the cortex is involved in LTH and that the neuronal substrates of STH and LTH are, in significant part, different.

Microneurosurgical techniques and perioperative strategies utilized to optimize experimental supracollicular decerebration in rats

“…Decortication removes the cortex of the cerebrum sans transection, sparing and preserving the diencephalic substance. Accordingly, the use of decorticate animals could putatively represents a useful alternative to the use of decerebrate preparations in studies evaluating neuronal microcircuit generating the breathing rhythm and pattern, sympathetic oscillations, cardiovagal premotoneuronal outflow, and hypothalamic, thalamic, and hippocampal rhythms (Baccelli et al, 1965;Dasgupta and Hausler, 1956;Imig and Durham, 2005;Klosterhalfen and Klosterhalfen, 1985;Palisses et al, 1988Palisses et al, , 1989.…”

Appearance of fetal pain could be associated with maturation of the mesodiencephalic structures

“…Decorticated experimental animals, such as the rat, also have behavioral patterns that resemble those of intact animals 24,25. Decerebrate and decorticate experimental animals show oral habituation, habituation to auditory and vibrotactile stimuli, and even classical conditioning of the eye blink reflex 26–31. The possibility of habituation and classical conditioning at the level of the mesodiencephalon shows its capability for learned modifications of the reflexes.…”