Table 1.

Estrogen-inducible changes in neuronal morphology

Model	Brain region	Morphological complexity	Spine number	Spine shape	Related outcomes	Refs
Cultured neurons	Hippocampus	Increased	Increased	NDa	ND	[16]
Cultured neurons	Cortex	Increased	ND	ND	ND	[16]
Cultured neurons	Basal Forebrain	Increased	ND	ND	ND	[16]
Mouseb	CA 1	ND	No change	Increased number of mushroom-shaped spines	Increased PSD95, spinophilin and syntaxin	[66,67]
Ratb	CA1	Increase in multiple synaptic boutons	Increased on apical and basal dendrites	ND	Improved spatial working memory correlated with an increase in spine density	[23,26]
Ratb	Medial amygdala	ND	Increased	ND	ND	[23]
Ratb	Hypothalamus	ND	Increased		ND	[23]
Ratb: estrus cycle	CA1 (apical dendrites)	ND	Increased in proestrus	ND	Spine number declined in estrus	[23,26]
Ratb: aged	CA1 (apical and basal dendrites)	ND	No change	ND	ND	[6]
Monkeyb: young African green (vervet)	CA1 striatum radiatum Dorsolateral PFC (layer I)	ND	Increased	ND	ND	[6,68]
Monkeyb: young and Aged Rhesus	CA1 striatum radiatum	ND	Increased	ND	Increased hippocampal-dependent memory task	[6]
Monkeyb: young Rhesus	Dorsolateral PFC (area 46; layer III)	ND	Increased	ND	No effect on delayed response	[68]
Monkeyb: aged (perimenopausal) Rhesus	Dorsolateral PFC (area 46; layer III)	No effect on age-associated decline in dendritic length	Increased	Partial reversal of age-associated loss of long-neck, small-spine head spines	Reversed age-associated decline in delayed response	[68]

^aND, not determined.

^bOvariectomized and treated with either vehicle or E₂.