Hodos W, Weiss S R, Bessette B B
Behav Brain Res. 1986 Sep;21(3):203-14. doi: 10.1016/0166-4328(86)90238-x.
Fifteen pigeons were tested in a psychophysical procedure that determined the limits of their ability to detect differences in the sizes of stimuli. The results indicated that intact pigeons can reliably discriminate an annulus 3.0 mm in diameter from one that is 3.9 mm in diameter. In the first experiment, pigeons with lesions of the ectostriatum that spared the medial 15% were unimpaired in their size-discrimination ability. Those cases in which the lesions involved both the medial and lateral regions of the ectostriatum were greatly impaired. In a second experiment, these findings were replicated. In some cases, the electrode trajectory was varied to rule out possible effects from non-ectostriatal structures. In addition, the second study indicated that destruction of the medial ectostriatum with the lateral regions intact had no measurable effect on size-difference thresholds. The medial region of ectostriatum is part of the termination field of a second tectofugal pathway to the telencephalon. This pathway passes from the optic tectum to nucleus dorsolateralis posterior thalami and then to the neostriatum intermedium, including the medial ectostriatum. An examination of the data of the present experiment and those of other behavioral studies of the ectostriatum suggest that the medial ectostriatum may be involved in the processing of visual information with low spatial-frequency components and the lateral ectostriatum may be processing information about the high-frequency composition of stimuli.
对15只鸽子进行了一项心理物理学实验，以确定它们检测刺激大小差异的能力极限。结果表明，正常的鸽子能够可靠地区分直径为3.0毫米的圆环和直径为3.9毫米的圆环。在第一个实验中，外纹状体受损但内侧15%未受损的鸽子在大小辨别能力上未受影响。而那些外纹状体的内侧和外侧区域均受损的鸽子则受到了极大的影响。在第二个实验中，重复了这些发现。在某些情况下，改变电极轨迹以排除非外纹状体结构可能产生的影响。此外，第二项研究表明，外侧区域完整而内侧外纹状体被破坏对大小差异阈值没有可测量的影响。外纹状体的内侧区域是第二条从视顶盖通向端脑的顶盖离中通路的终止场的一部分。这条通路从视顶盖通向丘脑后外侧背核，然后通向中间新纹状体，包括内侧外纹状体。对本实验数据以及其他关于外纹状体的行为学研究数据的检查表明，内侧外纹状体可能参与处理具有低空间频率成分的视觉信息，而外侧外纹状体可能处理有关刺激高频成分的信息。
