Disruption of the head direction cell signal after occlusion of the semicircular canals in the freely moving chinchilla.
Disruption of the head direction cell signal after occlusion of the semicircular canals in the freely moving chinchilla.
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DOI：
10.1523/jneurosci.3450-09.2009
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发表时间：
2009-11-18
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影响因子：
--
通讯作者：
Taube JS
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文献类型：
--
作者：
Muir GM;Brown JE;Carey JP;Hirvonen TP;Della Santina CC;Minor LB;Taube JS
大鼠丘脑前背核（ADN）中的头部方向（HD）细胞相对于动物的方向性头部放电。整个前庭迷路的病变以前已经被证明严重改变第VIII神经输入和破坏这些HD信号。为了评估半规管的具体贡献，而不改变紧张性第VIII神经输入，ADN细胞记录从龙猫双侧半规管闭塞。虽然ADN HD细胞（以及海马位置细胞和θ细胞）在完整的龙猫中被鉴定，但在椎管闭塞后没有观察到方向特异性活性。相反，观察到的“爆发性”细胞表现出与正常HD细胞相似的爆发性放电模式，但放电与动物的实际头部方向无关。重要的是，当记录成对的爆发细胞时，它们的放电时间顺序取决于动物的转向方向，就像正常HD细胞对的情况一样。这些结果表明，爆发细胞实际上是被破坏的HD细胞。目前的研究结果进一步表明，HD细胞网络仍然能够在半规管闭塞后产生尖峰活动，但半规管输入对于更新与动物HD变化相关的网络活动至关重要。
Head direction (HD) cells in the rat anterodorsal thalamic nucleus (ADN) fire relative to the animal’s directional heading. Lesions of the entire vestibular labyrinth have previously been shown to severely alter VIIIth nerve input and disrupt these HD signals. To assess the specific contributions of the semicircular canals without altering tonic VIIIth nerve input, ADN cells were recorded from chinchillas following bilateral semicircular canal occlusion. While ADN HD cells (and also hippocampal place cells and theta cells) were identified in intact chinchillas, no direction-specific activity was seen following canal occlusions. Instead, “bursty” cells were observed that exhibited burst-firing patterns similar to normal HD cells, but with firing unrelated to the animal’s actual head direction. Importantly, when pairs of bursty cells were recorded, the temporal order of their firing was dependent upon the animal’s turning direction, as is the case for pairs of normal HD cells. These results suggest that bursty cells are actually disrupted HD cells. The present findings further suggest that the HD cell network is still able to generate spiking activity following canal occlusions, but the semicircular canal input is critical for updating the network activity in register with changes in the animal’s HD.