Effects of Diagnostic Ultrasound Irradiated during Foetal Stage on Emotional and Cognitive Behaviour in Rats

Abstract

Our previous work demonstrated that the prenatally irradiated ultrasound of even a low-intensity might affect the functional development of the brain of offspring in rats. In the present study, in order to investigate the emotional and cognitive behaviour of offspring of rats that received the irradiation of a diagnostic ultrasound on the 9th day of gestation, the following three experiments were carried out: 1) The emotional reactivity of the offspring was measured by the open-field technique. 2) The same reactivity was further evaluated in terms of the escape response from electroshock. 3) The cognitive function of the offspring was assessed through the discrimination learning and the discrimination reversal learning. The offspring of irradiated rats showed significantly more distinct vocalization response to handling in the open-field test and significantly more distinct escape response from the electroshock, when compared with the two control rats (untreated control and sham-irradiated control). From these findings it may be suggested that the emotional behaviour in rats can be influenced by a low-intensity ultrasound irradiated during foetal stage. On the other hand, as for the cognitive behaviour, the results of the present study suggest no adverse effect on it.