Figure 3.

Effects of clonidine pretreatment and MK-801 treatment on performance in the radial arm maze. Animals were given two test runs with a delay of 30 seconds (30s) or 15 minutes (15m) between them on each trial. A. The asterisk indicates that animals pretreated with saline and treated with MK-801 made significantly more revisits to previously baited arms during the first test run relative to animals pretreated and treated with saline and animals pretreated with clonidine (0.05 mg/kg) and treated with MK-801 (0.1 mg/kg). B. Animals made significantly more incorrect choices during the first four arm entries after a 15-minute delay relative to a 30 second delay. C. After the delay, animals treated with MK-801 were more likely to visit arms previously baited during the first test run. Animals were also more likely to make such errors after a 15-minute delay relative to a 30-second delay. D. Animals treated with MK-801 revisited more baited arms during the second test run after the delay than did animals treated with saline. The single asterisks indicate significant differences between animals treated with saline relative to animals treated with MK-801 within the same pretreatment condition and same delay interval (i.e., the bar to the left of the asterisk). Animals pretreated and treated with saline made no revisits after the 15-minute delay. Data represent the average number for each measure (± s.e.m.) for each group. n = 6 per group.