Blood A J, Narayan S M, Toga A W
Department of Neurology, UCLA School of Medicine 90024, USA.
J Cereb Blood Flow Metab. 1995 Nov;15(6):1109-21. doi: 10.1038/jcbfm.1995.138.
Optical imaging of intrinsic signals was performed in the barrel cortex of the rat during whisker deflections of varying frequencies (1 to 20 Hz) and durations (0.1 to 5 s). A dose-response relationship was shown between these stimuli and the characteristics of the optically recorded intrinsic signal response. At constant frequencies, longer stimulus durations increased response magnitude, as defined by mean pixel value in statistically determined regions of interest. At constant durations, higher stimulus frequencies increased response magnitude. Response magnitude was also increased by greater numbers of deflections. When stimulus number was constant, there were no differences in response magnitude, regardless of stimulus frequency and duration. Spatial extent of responses, as defined by number of pixels in regions of interest, did not differ between stimulus frequencies, durations, or numbers. Comparison of the time to reach peak intrinsic signal response after stimulus onset ("time-to-peak") suggested that higher frequencies were associated with faster time-to-peak. Registration of intrinsic signal responses with cytochrome oxidase-stained whisker barrels demonstrated that responses were located over the barrel corresponding to the stimulated whisker. In summary, we have shown that the absolute number of stimuli delivered to the system is, at least for short stimulus periods (< or = 5 s), a determining factor for the magnitude of these responses, whereas stimulus frequency appears to influence time-to-peak response.
在不同频率（1至20赫兹）和持续时间（0.1至5秒）的触须偏转过程中，对大鼠的桶状皮质进行了内在信号的光学成像。这些刺激与光学记录的内在信号响应特征之间呈现出剂量反应关系。在恒定频率下，较长的刺激持续时间会增加响应幅度，响应幅度由统计学确定的感兴趣区域中的平均像素值定义。在恒定持续时间下，较高的刺激频率会增加响应幅度。更多的偏转次数也会增加响应幅度。当刺激次数恒定时，无论刺激频率和持续时间如何，响应幅度均无差异。由感兴趣区域中的像素数量定义的响应空间范围，在刺激频率、持续时间或次数之间没有差异。刺激开始后达到内在信号响应峰值的时间（“峰值时间”）比较表明，较高频率与更快的峰值时间相关。将内在信号响应与细胞色素氧化酶染色的触须桶进行配准表明，响应位于与受刺激触须相对应的桶上方。总之，我们已经表明，至少在短刺激期（≤5秒）内，传递到系统的刺激绝对数量是这些响应幅度的决定因素，而刺激频率似乎影响峰值时间响应。
