Lesions of the vestibular system disrupt hippocampal theta rhythm in the rat
Lesions of the vestibular system disrupt hippocampal theta rhythm in the rat
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DOI：
10.1152/jn.00953.2005
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发表时间：
2006-07-01
影响因子：
2.5
通讯作者：
Bilkey, David K.
中科院分区：
文献类型：
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作者：
Russell, Noah A.;Horii, Arata;Bilkey, David K.
海马体在空间定位记忆中起着重要作用。θ波是一种有节奏的海马脑电图振荡，在自主运动期间发生于类似于8赫兹的频率，可能在编码空间信息中起一定作用。作为这一过程的一部分，我们研究了theta是否可能受到前庭系统提供的自我运动信号的影响。在记录前60天制作>=双侧前庭周围病变，在自由活动大鼠中评估其影响。功率谱分析显示，与对照动物相比，受损动物的θ波功率和频率较低。当脑电图（EEG）在运动速度和加速度匹配的时期进行比较时，病变组的θ波节律性较差，表明这种影响不是这种行为的组间差异的结果。两组血液中皮质酮的测量结果也相似，这表明结果不能归因于压力水平的变化。尽管theta脑电图发生了变化，但受损动物CA1区的单个神经元继续以类似于8 Hz的周期性放电。在正常动物CA1神经元中观察到的细胞放电率与运动速度之间的正相关在病变组动物记录的细胞中也得以维持。这些发现表明，虽然前庭信号可能有助于θ节律的产生，但海马神经元中与速度相关的放电依赖于非前庭信号，如感觉流、本体感觉或运动感知复制。
The hippocampus has a major role in memory for spatial location. Theta is a rhythmic hippocampal EEG oscillation that occurs at similar to 8 Hz during voluntary movement and that may have some role in encoding spatial information. We investigated whether, as part of this process, theta might be influenced by self-movement signals provided by the vestibular system. The effects of bilateral peripheral vestibular lesions, made >= 60 days prior to recording, were assessed in freely moving rats. Power spectral analysis revealed that theta in the lesioned animals had a lower power and frequency compared with that recorded in the control animals. When the electroencephalography (EEG) was compared in epochs matched for speed of movement and acceleration, theta was less rhythmic in the lesioned group, indicating that the effect was not a result of between-group differences in this behavior. Blood measurements of corticosterone were also similar in the two groups indicating that the results could not be attributed to changes in stress levels. Despite the changes in theta EEG, individual neurons in the CA1 region of lesioned animals continued to fire with a periodicity of similar to 8 Hz. The positive correlation between cell firing rate and movement velocity that is observed in CA1 neurons of normal animals was also maintained in cells recorded from lesion group animals. These findings indicate that although vestibular signals may contribute to theta rhythm generation, velocity-related firing in hippocampal neurons is dependent on nonvestibular signals such as sensory flow, proprioception, or motor efference copy.