Running speed alters the frequency of hippocampal gamma oscillations.
Running speed alters the frequency of hippocampal gamma oscillations.
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DOI：
10.1523/jneurosci.5110-11.2012
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发表时间：
2012-05-23
期刊：
影响因子：
--
通讯作者：
Mehta MR
中科院分区：
文献类型：
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作者：
Ahmed OJ;Mehta MR
成功的空间导航被认为至少结合了两种策略：遵循地标提示和路径整合。路径整合要求大脑以一种有意义的方式使用运动的速度和方向来持续计算动物的位置。事实上，大鼠的跑步速度调节了神经元的放电速率和低频的频谱特性，在海马体的局部场电位（LFP）中可以看到，这是一个对空间记忆形成很重要的区域。频率较高的伽马波段LFP振荡通常与决策、注意力增加和反应时间缩短有关。在这里，我们发现跑步速度的增加伴随着海马CA1网络在整个伽马范围（30-120 Hz）及更大范围内振荡频率的大幅度系统性增加。这些与速度相关的频率变化在线性轨道和二维平台上都可以看到，因此与行为任务无关。解剖学上距离较远的CA1区域之间的同步也随着跑步速度的增加而转向更高的伽马频率。频率的变化与单个中间神经元放电速率的变化密切相关，这与伽马产生的模型一致。我们的研究结果表明，当老鼠跑得更快时，顺序位置细胞集合之间的伽马频率转换也会更快。这可能有助于在不同的跑步速度下保持位置细胞和空间记忆的空间特异性。
Successful spatial navigation is thought to employ a combination of at least two strategies: the following of landmark cues and path integration. Path integration requires that the brain use the speed and direction of movement in a meaningful way to continuously compute the position of the animal. Indeed, the running speed of rats modulates both the firing rate of neurons and the spectral properties of low frequency, theta oscillations seen in the local field potential (LFP) of the hippocampus, a region important for spatial memory formation. Higher frequency, gamma-band LFP oscillations are usually associated with decision-making, increased attention and improved reaction times. Here, we show that increased running speed is accompanied by large, systematic increases in the frequency of hippocampal CA1 network oscillations spanning the entire gamma range (30–120 Hz) and beyond. These speed-dependent changes in frequency are seen on both linear tracks and two-dimensional platforms, and are thus independent of the behavioral task. Synchrony between anatomically distant CA1 regions also shifts to higher gamma frequencies as running speed increases. The changes in frequency are strongly correlated with changes in the firing rates of individual interneurons, consistent with models of gamma generation. Our results suggest that as a rat runs faster, there are faster gamma frequency transitions between sequential place cell-assemblies. This may help to preserve the spatial specificity of place cells and spatial memories at vastly different running speeds.