Department of Anatomy/Neurobiology, University of California-Irvine, Irvine, California 92697, USA.
Department of Pediatrics, University of California-Irvine, Irvine, California 92697, USA.
Learn Mem. 2019 Jun 17;26(7):206-218. doi: 10.1101/lm.049239.118. Print 2019 Jul.
Spatial memory, the aspect of memory involving encoding and retrieval of information regarding one's environment and spatial orientation, is a complex biological function incorporating multiple neuronal networks. Hippocampus-dependent spatial memory is not innate and emerges during development in both humans and rodents. In children, nonhippocampal dependent egocentric (self-to-object) memory develops before hippocampal-dependent allocentric (object-to-object) memory. The onset of allocentric spatial memory abilities in children around 22 mo of age occurs at an age-equivalent time in rodents when spatially tuned grid and place cells arise from patterned activity propagating through the entorhinal-hippocampal circuit. Neuronal activity, often driven by specific sensory signals, is critical for the normal maturation of brain circuits This patterned activity fine-tunes synaptic connectivity of the network and drives the emergence of specific firing necessary for spatial memory. Whereas normal activity patterns are required for circuit maturation, aberrant neuronal activity during development can have major adverse consequences, disrupting the development of spatial memory. Seizures during infancy, involving massive bursts of synchronized network activity, result in impaired spatial memory when animals are tested as adolescents or adults. This impaired spatial memory is accompanied by alterations in spatial and temporal coding of place cells. The molecular mechanisms by which early-life seizures lead to disruptions at the cellular and network levels are now becoming better understood, and provide a target for intervention, potentially leading to improved cognitive outcome in individuals experiencing early-life seizures.
空间记忆是一种涉及到对自身环境和空间方位信息的编码和检索的记忆方面，它是一个复杂的生物功能，涉及多个神经元网络。海马依赖的空间记忆不是天生的，而是在人类和啮齿动物的发育过程中逐渐出现的。在儿童中，非海马依赖的自我中心（自我到物体）记忆先于海马依赖的客体中心（物体到物体）记忆发展。儿童大约在 22 个月大时开始出现客体中心空间记忆能力，这与啮齿动物中空间调谐网格和位置细胞从通过内侧颞叶-海马回路传播的模式活动中出现的年龄相当。神经元活动，通常由特定的感觉信号驱动，对于大脑回路的正常成熟至关重要。这种模式活动可以精细调节网络的突触连接，并驱动特定的放电出现，从而实现空间记忆。虽然正常的活动模式对于回路成熟是必需的，但发育过程中的异常神经元活动可能会产生重大的不利后果，破坏空间记忆的发展。婴儿期的癫痫发作涉及到大量同步网络活动的爆发，当动物在青少年或成年时进行测试时，会导致空间记忆受损。这种受损的空间记忆伴随着位置细胞的空间和时间编码的改变。早期生活中癫痫发作导致细胞和网络水平破坏的分子机制现在已经得到更好的理解，并为干预提供了一个目标，有可能改善经历早期生活中癫痫发作的个体的认知结果。
