In vivo study of left-right differences of the rodent hippocampus

虽然大脑的左右不对称在普通人群中是众所周知的，但其生理意义仍然不清楚。为了探讨动物经验如何影响大脑的不对称性，我们记录了局部场电位的大鼠双侧从大鼠在丰富的环境（ENR）和那些在隔离条件下饲养（ISO）。我们发现，功率的伽马振荡往往是更大的大鼠饲养在ENR比那些饲养在ISO。这种经验依赖性伽马增强在所有受试者的右侧海马体中始终较大，与右侧海马体中突触密度的偏侧增加一致。此外，ENR组的半球间相干性在伽马频率下显著升高。这些结果表明ENR饲养通过突触重组塑造了海马回路的功能性左右不对称性。

Though left-right asymmetry of the brain is well known among the general population, the physiological meanings remain unclear. To investigate how animal experience influence on brain asymmetry, we recorded local field potentials of rat hippocampi bilaterally from rat reared in enriched environment (ENR) and those reared in isolated condition (ISO). We found that the power of gamma oscillations tends to be greater in rats reared in ENR than those reared in an ISO. This experience-dependent gamma enhancement is consistently larger in the right hippocampus across subjects, coinciding with a lateralized increase of synaptic density in the right hippocampus. Moreover, interhemispheric coherence in ENR group is significantly elevated at the gamma frequency. These results suggest that ENR rearing sculpts the functional left-right asymmetry of hippocampal circuits by reorganization of synapses.