High-frequency whisker vibration is encoded by phase-locked responses of neurons in the rat's barrel cortex
High-frequency whisker vibration is encoded by phase-locked responses of neurons in the rat's barrel cortex
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DOI：
10.1523/jneurosci.0089-08.2008
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发表时间：
2008-05-14
影响因子：
5.3
通讯作者：
Engel, Andreas K.
中科院分区：
文献类型：
--
作者：
Ewert, Tobias A. S.;Vahle-Hinz, Christiane;Engel, Andreas K.
大鼠在触觉探索过程中用胡须进行纹理辨别，具有很高的空间和时间精度。虽然外周机械感受器提供触觉信息与精致的时间分辨率，生理学研究表明，这种信息可能会丢失在皮层水平。为了解决这一差异，多单位和单单位记录进行了在桶皮质的异氟烷麻醉大鼠使用连续正弦振动的单须在15-700 Hz。在多单元记录中，持续的锁相反应发生在700 Hz的振动频率，1：1刺激锁定观察到高达320 Hz。多单元的宽带响应显示频率编码在20和320 Hz之间。在低频和高频范围内的刺激的放电率没有不同，但他们显着降低非锁相响应高频振动。只有25%的情况下，目前的反应适应，而在大多数情况下，夹带的振动频率保持不变，甚至增加刺激持续时间。增加夹带高频刺激伴随着出现的诱导活动的γ波段范围内。单单位活动的分析表明，锁相振动刺激比观察到的多单位的反应更精确。结果表明，在100 Hz以上的频率的晶须振动忠实地编码的持续锁相反应的皮层神经元异氟烷麻醉。可以想象的是，清醒的动物利用甚至更高频率的触觉信号，这可以在纹理辨别期间由外周机械感受器提供。
Rats perform texture discrimination during tactile exploration with their whiskers with high spatial and temporal precision. Although the peripheral mechanoreceptors provide tactile information with exquisite temporal resolution, physiological studies have suggested that this information might be lost at the cortical level. To address this discrepancy, multiunit and single-unit recordings were performed in the barrel cortex of isoflurane-anesthetized rats using continuous sinusoidal vibration of single whiskers at 15-700 Hz. In multiunit recordings, sustained phase-locked responses occurred up to vibration frequencies of 700 Hz, and 1: 1 stimulus locking was observed up to 320 Hz. Wide-band responses of multiunits showed frequency encoding between 20 and 320 Hz. The discharge rates were not different for stimuli in the low-and high-frequency ranges, but they were significantly lower for non-phase- locked responses to high-frequency vibration. Response adaptation was present in only 25% of the cases, whereas in the majority of cases, entrainment to the vibratory frequency remained constant or even increased with stimulus duration. Increased entrainment to high-frequency stimulation was accompanied by the emergence of induced activity in the gamma-band range. Analysis of single-unit activity revealed that phase locking to vibratory stimuli was more precise than that observed for the multiunit responses. The results show that whisker vibrations at frequencies above 100 Hz are faithfully encoded by sustained phase-locked responses of cortical neurons under isoflurane anesthesia. It is conceivable that the awake animal makes use of the tactile signals at even much higher frequencies, which can be provided by the peripheral mechanoreceptors during texture discrimination.