ABNORMAL HIPPOCAMPAL SPATIAL REPRESENTATIONS IN ALPHA-CAMKIIT286A ANDCREB-ALPHA-DELTA- MICE

Hippocampal ''place cells'' fire selectively when an animal is in a sp ecific location. The fine-tuning and stability of place cell firing wa s compared in two types of mutant mice with different long-term potent iation (LTP) and place learning impairments. Place cells from both mut ants showed decreased spatial selectivity. Place cell stability was al so deficient in both mutants and, consistent with the severities in th eir LTP and spatial learning deficits, was more affected in mice with a point mutation [threonine (T) at position 286 mutated to alanine (A) ] in the alpha calmodulin kinase II (alpha CaMKIIT286A) than in mice d eficient for the a and a isoforms of adenosine 3'5'-monophosphate-resp onsive element binding proteins (CREBalpha Delta-). Thus, LTP appears to be important for the fine tuning and stabilization of place cells, and these place cell properties may be necessary for spatial learning.