The effects of social isolation on the spatial and nonspatial cognitive ability in mice

Abstract

Objective To study the effects of social isolation (SI)on the spatial and nonspatial cognitive ability in mice.Methods The postnatal 21 day kunming mice were divided into control group,SI 2 weeks group,SI 4 weeks group,SI 8 weeks group and SI 2 weeks gregarious group according to randomized block design,with ten animals each.SI 2 weeks group,SI 4 weeks group and SI 8 weeks group were isolated for 2,4 and 8 weeks respectively,SI 2 weeks gregarious group would be housed under normal grouped housing condition after 2 weeks isolation until adult,the relative control groups were the same age as the relative SI and SI gregarious group.All animals were measured the spatial and nonspatial cognitive ability by carrying the object recognition test(ORT) and object location test (OLT) after the treatment.Results In the ORT,compared to the relative control group,the discrimination index in the SI 2 weeks group,SI 4 weeks group and SI 8 weeks group ( ( - 0.03 ± 0.003 ),( - 0.11 ±0.02) and( - 0.21 ± 0.02 ) respectively) were strikingly lower than the relative control group ( ( 0.29 ± 0.03 ),(0.13±0.07) and (0.09 ±0.03) respectively) (P＜0.05).In the OLT,compared to the relative control group,the discrimination index in the SI 2 weeks group,SI 4 weeks group and SI 8 weeks group( ( -0.15 ±0.02),( -0.30± 0.02),( - 0.32 ± 0.02 ) respectively ) were strikingly lower than the relative control group ( (0.33 ± 0.02 ),(0.41 ± 0.03 ),(0.27 ± 0.04)respectively)(P＜ 0.05 ),while the SI 2 weeks gregarious group with the resocialization to the normal housing condition showed no change.Conclusions 2 weeks,4 weeks and 8 weeks isolation on mice lead to the spatial and nonspatial cognition deficits,while the resocialization to the normal housing condition could recover the damage. Key words: Social isolation; Spatial cognitive ability; Nonspatial cognitive ability