Philosophy

In the article of Robert McDonald, Nancy Hong, Laura Craig, Matthew Holahan, Meira Louis, and Robert Muller (2005), the role of the NMDA-receptor mediated plasticity in the post-training memory revealed that this receptor carries a substantial effect in the process of new location training, especially concerning long term memory.  The trace for the new location learned during the blockade appeared to be much weaker when compared with the trace for the new location some 24 hours after the saline injection.  This suggests a memory consolidation effect, reinforcing the notion that the NMDA receptors appear to be essential in the transferring from short memory to long term memory, but are not necessary in retaining navigational information in the short term alone.  The water maze methods used in the article of McDonald et al. (2005) uses the transfer test first before the probe test, indicating that the blockade of NMDA likewise blocks the ability to transfer long term memory, especially that it helps consolidate information from short term memory to long term memory.    

In the article of Richard Morris (1981), however, it reveals that fixed spatial location relative to distant room cues is necessary in locating an object, but transfer tests do reveal that spatial location search strategy show strong directional bias toward their respective training quadrant.  There appear to be no directional biases by the escape training as indicated in the performance.  The results show a marked decrease in the speed of the response to reach its medium and no obvious sign that it has learned to ignore place cues.  This leads to the conclusion that rats learn to find an object that they cannot see, hear, or smell, by locating its position in a familiar space (Morris, 1981, p.252).

Moreover, they show good directionality paths as localization is learned quickly.  Although farther cues from a point of reference are sufficient in determining location, the nearest cues would be sufficient enough to get the animals to their destined location.  Memory consolidation effect appears to be substantial in determining location, and that NMDA has suggestive account in the transfer of memory.