Table 1.

Changes in the hippocampus or in hippocampus-dependent functions.

	Aging	Alzheimer disease	Depression	trkB- or BDNF-deficient mice
Hippocampal volume	Reduced	Reduced	Reduced	Reduced
Loss of hippocampal neurons	No	Yes	No	Minor
Hippocampal spine densities	Reduced		Reduced	Reduced
Neurogenesis	Reduced	Increased1	Reduced	Reduced2
LTP	Reduced	Reduced3	Reduced4	Reduced
Spatial learning	Reduced	Reduced5	Reduced6	Reduced

Several of these alterations are also seen in trkB- or BDNF-deficient mouse models.

¹Jin et al. (2004).

²As determined by a trkB-deficient mouse line (Li et al., 2008).

³Data from mouse models of AD (Nalbantoglu et al., 1997; Smith et al., 2009; Auffret et al., 2010; Gengler et al., 2010).

⁴Data from “learned helplessness”, an animal model of depression (Ryan et al., 2009).

⁵Data from mouse models of AD (Moran et al., 1995; Nalbantoglu et al., 1997; Gordon et al., 2001).