Spontaneous alternation in Mesocricetus auratus: Age differences

Apparatus design and behavioural testing protocol for the evaluation of spatial working memory in mice through the spontaneous alternation T-maze

Spatial working memory can be assessed in mice through the spontaneous alternation T-maze test. The T-maze is a T-shaped apparatus featuring a stem (start arm) and two lateral goal arms (left and right arms). The procedure is based on the natural tendency of rodents to prefer exploring a novel arm over a familiar one, which induces them to alternate the choice of the goal arm across repeated trials. During the task, in order to successfully alternate choices across trials, an animal has to remember which arm had been visited in the previous trial, which makes spontaneous alternation T-maze an optimal test for spatial working memory. As this test relies on a spontaneous behaviour and does not require rewards, punishments or pre-training, it represents a particularly useful tool for cognitive evaluation, both time-saving and animal-friendly. We describe here in detail the apparatus and the protocol, providing representative results on wild-type healthy mice.

Emergence of spontaneous alternation in the kitten

Two studies are reported that describe the development of spontaneous alternation in the kitten. The first indicates that 3- and 4-week-old kittens do not alternate whereas animals 5 weeks and older do alternate. The second suggests that inability to discriminate maze arms is an unlikely explanation for the lack of alternation among the youngest animals. The approximate simultaneity between the onset of alternation (described here) and the maturation of the kitten hippocampus (described by others) is taken as support for the notion that hippocampal maturation may be related to the development of spontaneous alternation.

Changes in developing behavior following prenatal administration of imipramine

Female rats were given oral doses of Imipramine (5mg/kg) from 14-21 days prior to mating to conception or Day 19 or gestation and the physical maturation and behavioral development of their offspring was compared with that of controls. There were significant differences between the weights of the Imipramine and control animals at 21 days and the appearance of some reflexes was delayed. Behavior in an open field was observed when the rats were 9, 13, 17 and 21 days of age and it was found that exploratory responses were less frequent in the drug exposed offspring. In contrast there were no obvious physical anomalies and the adult behavior of the Imipramine animals on a spontaneous alternation task and a swimming maze did not differ from that of controls.