Ainge James A, Heron-Maxwell Claire, Theofilas Panos, Wright Paul, de Hoz Livia, Wood Emma R
Laboratory for Cognitive Neuroscience, Division of Neuroscience and Centre for Neuroscience Research, 1 George Square, Edinburgh, EH8 9JZ, UK.
Behav Brain Res. 2006 Feb 15;167(1):183-95. doi: 10.1016/j.bbr.2005.09.005. Epub 2005 Oct 7.
Studies examining the effects of hippocampal lesions on object recognition memory in rats have produced conflicting results. The present study investigated how methodological differences and lesion size may have contributed to these discrepancies. In Experiment 1 we compared rats with complete, partial (septal) and sham hippocampal lesions on a spontaneous object recognition task, using a protocol previously reported to result in deficits following large hippocampal lesions . Rats with complete and partial hippocampal lesions were unimpaired, suggesting the hippocampus is not required for object recognition memory. However, rats with partial lesions showed relatively poor performance raising the possibility that floor effects masked a deficit on this group. In Experiment 2, we used a second spontaneous object recognition protocol similar to that used by the two other studies that have reported deficits following hippocampal lesions . Rats with complete hippocampal lesions were significantly impaired, whereas rats with partial lesions were unimpaired. However, the complete lesion group showed less object exploration during the sample phase. Thus, the apparent recognition memory deficit in Experiment 2 may be attributable to differential encoding. Together, these findings suggest that the hippocampus is not required for intact spontaneous object recognition memory. These findings suggest that levels of object exploration during the sample phase may be a critical issue, and raise the possibility that previous reports of object recognition deficits may be due to differences in object exploration rather than deficits in object recognition per se.
研究海马体损伤对大鼠物体识别记忆的影响产生了相互矛盾的结果。本研究调查了方法学差异和损伤大小可能如何导致了这些差异。在实验1中，我们使用先前报道的在大型海马体损伤后会导致缺陷的方案，在自发物体识别任务中比较了具有完整、部分（隔区）和假海马体损伤的大鼠。具有完整和部分海马体损伤的大鼠未受损，这表明物体识别记忆不需要海马体。然而，部分损伤的大鼠表现相对较差，这增加了地板效应掩盖该组缺陷的可能性。在实验2中，我们使用了第二种自发物体识别方案，该方案类似于另外两项报道海马体损伤后出现缺陷的研究中所使用的方案。具有完整海马体损伤的大鼠明显受损，而部分损伤的大鼠未受损。然而，完整损伤组在样本阶段的物体探索较少。因此，实验2中明显的识别记忆缺陷可能归因于不同的编码。总之，这些发现表明完整的自发物体识别记忆不需要海马体。这些发现表明样本阶段的物体探索水平可能是一个关键问题，并增加了先前物体识别缺陷报告可能是由于物体探索差异而非物体识别本身缺陷的可能性。
