Buyukata Cem, Vukalo Milijana, Xu Tanya J, Khore Madhavi A, Reichelt Amy C
School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
Physiol Behav. 2018 Aug 1;192:127-133. doi: 10.1016/j.physbeh.2018.02.027. Epub 2018 Feb 16.
High sucrose diets (HSDs) have been shown to have detrimental effects on hippocampal dependent memory in rats, including the performance of spatial tasks reliant on pattern separation, a cognitive process involved in minimising interference during memory encoding. As such we sought to investigate the impact of HSDs on object and spatial recognition tasks that varied the cognitive load placed on pattern separation processes. Young male and female rats were 4 weeks old at the start of diet manipulations. Rats in the HSD condition were provided with daily access to 10% sucrose solution for 2 h per day across a 28 d period, during which they were assessed on their performance of memory tasks that varied the similarity of spatial arrangements (Spontaneous Location Recognition, SLR) and object features (Novel Object Recognition, NOR) to determine the effect of HSD on memory encoding processes. Both female and male rats that consumed HSDs were impaired at NOR when objects shared multiple features (s-NOR), however when objects were distinct, novel object recognition was not impacted by HSD consumption. Male rats in the control condition generally outperformed female rats in the SLR task when there were small spatial separations (s-SLR) but not when there were large spatial separations (d-SLR). HSD consumption disrupted performance of d-SLR in female rats, but not male rats. Specific HSD deficits were observed in HSD consuming male rats in the s-SLR task. However, the volume of sucrose consumed differed between sexes, and may have impacted memory differentially. These findings indicate that HSD-induced memory deficits may extend to pattern separation dependent recognition memory mechanisms when objects share overlapping features, and impairments in spatial tasks may be more pronounced in female rats.
高蔗糖饮食（HSDs）已被证明会对大鼠海马体依赖性记忆产生有害影响，包括依赖模式分离的空间任务表现，模式分离是一种在记忆编码过程中减少干扰的认知过程。因此，我们试图研究高蔗糖饮食对物体和空间识别任务的影响，这些任务改变了施加在模式分离过程上的认知负荷。在饮食操作开始时，年轻的雄性和雌性大鼠为4周龄。高蔗糖饮食组的大鼠在28天的时间里，每天有2小时可以饮用10%的蔗糖溶液，在此期间，它们接受了记忆任务的评估，这些任务改变了空间排列（自发位置识别，SLR）和物体特征（新物体识别，NOR）的相似性，以确定高蔗糖饮食对记忆编码过程的影响。当物体具有多个共同特征时（s-NOR），食用高蔗糖饮食的雌性和雄性大鼠在新物体识别任务中均受损，然而，当物体不同时，高蔗糖饮食对新物体识别没有影响。在空间间隔较小时（s-SLR），对照组的雄性大鼠在自发位置识别任务中的表现通常优于雌性大鼠，但在空间间隔较大时（d-SLR）则不然。食用高蔗糖饮食会破坏雌性大鼠在d-SLR任务中的表现，但对雄性大鼠没有影响。在s-SLR任务中，食用高蔗糖饮食的雄性大鼠出现了特定的高蔗糖饮食缺陷。然而，两性消耗的蔗糖量不同，这可能对记忆产生不同的影响。这些发现表明，当物体具有重叠特征时，高蔗糖饮食诱导的记忆缺陷可能扩展到依赖模式分离的识别记忆机制，并且空间任务中的损伤在雌性大鼠中可能更明显。
