Chino Y M, Ridder W H, Czora E P
Electrophysiology Laboratory, Illinois College of Optometry, Chicago 60616.
Exp Brain Res. 1988;72(2):264-78. doi: 10.1007/BF00250249.
Single-cell recording experiments were carried out to determine whether rearing kittens with surgically induced convergent strabismus (esotropia) alters the development of receptive field (RF) properties of neurons in area 18. In agreement with previous work on kittens with divergent strabismus (exotropia), there was a marked loss of binocularly driven cells in area 18 of esotropic cats. In contrast to the striate cortex of strabismic cats, the spatial properties of area 18 neurons, including receptive-field size and spatial frequency tuning, did not differ from those in normal controls. On the other hand, we found that contrast thresholds, measured at an optimal spatial frequency, were significantly elevated, and that the contrast gain in many cells was reduced in strabismic cats. These deficits were observed in both eyes, though the cells dominated by the deviating eye had a lower response amplitude at all contrasts. Furthermore, temporal frequency tuning curves were abnormal in strabismic cats in that the optimal frequencies and temporal resolutions were shifted to lower values. These effects were also bilateral. Velocity tuning, measured with a high-contrast bar stimulus, revealed that area 18 neurons in strabismic cats were unable to respond to very high velocities compared to normals. This reduced response was more severe when measured with the deviating eye in spite of the bilateral nature of the deficit. Finally, latencies to electrical stimulation of the optic chiasm or the optic radiation were significantly longer in strabismic cats. The magnitude of these effects was virtually the same for both eyes. From these observations, we conclude that the temporal properties of area 18 neurons, particularly the cells abilities to follow fast temporal modulations, are affected by raising kittens with surgically induced convergent strabismus.
进行单细胞记录实验以确定用手术诱导的会聚性斜视（内斜视）饲养小猫是否会改变18区神经元感受野（RF）特性的发育。与先前关于患有发散性斜视（外斜视）小猫的研究一致，内斜视猫的18区中双眼驱动细胞明显减少。与斜视猫的纹状皮层不同，18区神经元的空间特性，包括感受野大小和空间频率调谐，与正常对照组并无差异。另一方面，我们发现，在最佳空间频率下测量的对比度阈值显著升高，并且斜视猫的许多细胞的对比度增益降低。两只眼睛均观察到这些缺陷，尽管在所有对比度下，由偏斜眼主导的细胞的反应幅度较低。此外，斜视猫的时间频率调谐曲线异常，因为最佳频率和时间分辨率都向较低值偏移。这些影响也是双侧的。用高对比度条形刺激测量的速度调谐显示，与正常猫相比，斜视猫的18区神经元无法对非常高的速度做出反应。尽管缺陷具有双侧性，但用偏斜眼测量时，这种反应降低更为严重。最后，斜视猫对视交叉或视辐射进行电刺激的潜伏期明显更长。两只眼睛的这些影响程度几乎相同。从这些观察结果中，我们得出结论，18区神经元的时间特性，特别是细胞跟随快速时间调制的能力，会受到用手术诱导的会聚性斜视饲养小猫的影响。
