Heroin impairs map-picture-following and memory tasks dependent on gender and orientation of the tasks.

Male and female heroin-dependent patients (HDPs) matched with "normal" people were tested on 4 topographical orientation tasks: schematic map-following, map-memory, schematic picture-following, and picture-memory tasks. The results showed that, in general, female HDPs demonstrated greater performance deficits in map-following and map-picture-memory tasks than did other participants. In the map-picture-following tasks, participants showed a preference for turning right versus turning left, reflected by lower correct scores and longer latencies in completing left-oriented tasks. In contrast, no difference in orientation preference was found for participants in memory tasks, except for female HDPs. Asymmetric dopamine receptor distribution in the brain, sex steroidal hormone, brain areas related to motor functioning and working memory, and gender-dependent lateralization may be involved in the different effects of heroin and rightward bias between men and women.

Learning large-scale spatial relationships in a maze and effects of MK-801 on retrieval in the rhesus monkey.

Monkeys have strong abilities to remember the visual properties of potential food sources for survival in the nature. The present study demonstrated the first observations of rhesus monkeys learning to solve complex spatial mazes in which routes were guided by visual cues. Three monkeys were trained in a maze (6 m x 6 m) included of four different mazes. We recorded the cue and cup errors, latencies, and pathway for each trial. The data showed that monkeys learned the target place after three days in the first maze and spent a shorter time in learning the following mazes. The maze was an efficient method to measure the ability and proceeding of spatial memory in monkeys. Moreover, working memory can also be tested by using the maze. MK-801 at 0.02 mg/kg but not at 0.005 mg/kg impaired monkeys' retrieval of spatial memory after they learned all four mazes. The present maze may provide an efficient method to help bridging the gap in cognition between nonhuman primates and humans, and in particular to gain insight into human cognitive function and dysfunction.