Avoidance learning step-down

Ginseng extract improves the spatial learning performance of aged rats in an eight-arm radial maze and operant discrimination task (Nitta et al. 1995). It also improves memory performance in active-avoidance (shuttle-box) and passive-avoidance (step-down) tasks, and reinforces staircase-maze learning in both young and aged rats. (Petkov and Mosharrof 1987 Petkov et al. 1990 Petkov et al. 1992). The effects were also very dose dependent, with inverted U-shape dose-response curves. 

The role in learning and memory processes of neuronal versus mast cell-derived HA has also been investigated. Histamine, administered icv immediately post-training have been shown to increase memory in a step-down inhibitory avoidance task.3 However, 48/80, a mast cell HA releaser, was ineffective in producing cognition enhancement when administered icv.4 These findings indicate that neuronally derived HA is responsible for the improvements in learning and memory tasks. 

Kameyama T, Nabeshima T, Kosawa T (1986) Step-down-type passive avoidance- and escape-learning method. Suitability for experimental amnesia models. J Pharmacol Meth 16 39-52... 

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