Intact spatial learning and memory in transgenic mice with reduced BDNF.

Long-term potentiation (LTP) in hippocampal CA1 pyramidal cells is considered to be a cellular analogue of learning and may be useful in studying the molecular foundations of learning and memory. Because brain-derived neurotrophic factor (BDNF) had been shown to have a role in activity-dependent neuroplasticity in the hippocampus we studied spatial learning in mice with BDNF deficiency produced by gene-targeted mutation. Heterozygous BDNF knockout mice reportedly underexpress BDNF and have reduced LTP, but their spatial memory and search strategy assessed with Morris water maze (distally cued version) as well as their performance on the elevated plus maze were indistinguishable from that of controls. This indicates that extrapolation from LTP in a single brain structure to complex behaviours such as learning and memory may not be justified.