Formation of a place learning-set by the rat: a new paradigm for neurobehavioral studies

The Morris water swimming task provides an ideal way of studying spatial navigational abilities in rats. It requires that rats swim to find a platform located just below the surface of the water in a swimming pool, and rats will learn and perform the task readily without being subject to nutrient deprivation. A novel adaption of the task, in which rats are shown to form a place learning-set, is described in the present paper. The learning-set paradigm can be used for the repeated evaluation of spatial navigation abilities in the same animals over a long period of time. The procedure is based on the finding that once trained, rats can acquire a new place response each day. Each new response can be learned within one or two trials, given within the time period of a few seconds, and once acquired, the response can be retained for a number of days, or until the problem is changed. The procedure can be usefully applied to the study of recovery of function following brain damage, the study of memory processes following brain damage, the changes in memory processes accompanying aging, or it can be used for the screening of pharmacological compounds, etc. The technique may be especially useful for the study of the performance of individual rats.     

人参皂甙Rg1对慢性应激大鼠空间学习记忆能力的影响

目的　探讨人参皂甙Rg1对慢性应激大鼠空间学习记忆能力的影响及初步机制。方法　采用电击足底结合噪声建立慢性应激大鼠模型 ,Morris水迷宫观察动物的空间学习和记忆能力 ,Niss染色观察和计数海马神经元为数量 ,Fara 2荧光法测海马突触体内游离钙浓度。结果　腹腔注射 5 0mg/kg人参皂甙Rg1对慢性应激引起的空间学习和记忆能力下降 ,海马神经元数量减少 ,海马突触体内游离钙浓度增高有明显保护作用 ,而注射 10mg/kg人参皂甙Rg1的效果不明显。结论　人参皂甙Rg1对慢性应激性认知障碍有保护作用 ,其机制可能是通过调节海马细胞内的钙浓度 ,防止海马神经细胞丢失有关。     

Ganglioside GQ1b improves spatial learning and memory of rats as measured by the Y-maze and the Morris water maze tests

Gangliosides are major components of cell membranes and are particularly enriched in the mammalian brain where they represent the major lipid constituents of the neuronal cell surface. In the central nervous system, gangliosides have a close connection to many neurophysiological functions related to neurogenesis, proliferation, synaptogenesis, and synaptic transmission. The previously reported effect of the tetra-sialoganglioside GQ1b in hippocampal CA1 neurons of brain slices showed that GQ1b enhanced ATP-induced long-term potentiation (LTP). However, there has been no clear evidence of the effects of GQ1b on learning and memory as measured using behavioral test. In the present study, we performed the Y-maze and the Morris water maze (MWM) tests to reveal the effects of GQ1b on spatial learning and memory following intracerebroventricular (ICV) injection of GQ1b. GQ1b-treated rats showed highly increased performance on the Y-maze and the MWM tests without any significant alteration of basal locomotor activity. Therefore, our behavioral data strongly suggest that GQ1b improves spatial learning and memory in rats. Also, these data support the previous finding that GQ1b treatment in hippocampal CA1 neurons of rodent brain slices increased ATP-induced LTP.