PT  - JOURNAL ARTICLE
AU  - Packard, MG
AU  - Hirsh, R
AU  - White, NM
TI  - Differential effects of fornix and caudate nucleus lesions on two radial maze tasks: evidence for multiple memory systems
AID  - 10.1523/JNEUROSCI.09-05-01465.1989
DP  - 1989 May 01
TA  - The Journal of Neuroscience
PG  - 1465--1472
VI  - 9
IP  - 5
4099  - http://www.jneurosci.org/content/9/5/1465.short
4100  - http://www.jneurosci.org/content/9/5/1465.full
SO  - J. Neurosci.1989 May 01; 9
AB  - The present experiments were designed to examine the hypothesis that the mammalian brain contains anatomically distinct memory systems. Rats with bilateral lesions of caudate nucleus or fimbria-fornix and a control group were tested postoperatively on 1 of 2 versions of the radial maze task. In a standard win-shift version, each of the 8 arms of the maze was baited once, and the number of errors (revisits) in the first 8 choices of each trial was recorded. Fimbria-fornix rats were impaired in choice accuracy, while caudate animals were unimpaired relative to controls. Different groups of rats with similar lesions were tested on a newly developed win-stay version of the radial maze, in which the location of 4 randomly selected baited arms was signaled by a light at the entrance to each arm, and which required rats to revisit arms in which reinforcement had been previously acquired within a trial. Rats with fimbria-fornix lesions were superior to controls in choice accuracy on the win-stay radial maze task, while caudate animals were impaired relative to controls. The results demonstrate a double dissociation of the mnemonic functions of the hippocampus and caudate nucleus. Some implications of the presence of 2 memory systems in the mammalian brain are discussed.