Felleman Daniel J, Lim Heejin, Xiao Youping, Wang Yi, Eriksson Anastasia, Parajuli Arun
Department of Neurobiology and Anatomy, University of Texas Medical School-Houston, Houston, TX 77030, USA.
Department of Neurobiology and Anatomy, University of Texas Medical School-Houston, Houston, TX 77030, USA Department of Computer Science, Prairie View A&M University, Prairie View, TX, USA.
Cereb Cortex. 2015 Sep;25(9):2354-69. doi: 10.1093/cercor/bhu033. Epub 2014 Mar 9.
Area V2 of macaque monkeys is traditionally thought to consist of 3 distinct functional compartments with characteristic cortical connections and functional properties. Orientation selectivity is one property that has frequently been used to distinguish V2 stripes, however, this receptive field property has been found in a high percentage of neurons across V2 compartments. Using quantitative intrinsic cortical imaging, we derived maps of preferred orientation, orientation selectivity, and orientation gradient in thin stripes, thick stripes, and interstripes in area V2. Orientation-selective responses were found in each V2 stripe, but the magnitude and organization of orientation selectivity differed significantly from stripe to stripe. Remarkably, the 2 pale stripes flanking each cytochrome oxidase dense stripe differed significantly in their representation of orientation resulting in their distinction as type-I and type-II interstripes. V2 orientation maps are characterized by clockwise and anticlockwise "orientation pinwheels", but unlike V1, they are not homogeneously distributed across V2. Furthermore, V2 stripes contain large-scale sequences of preferred orientation. These analyses demonstrate that V2 consists of 4 distinct functional compartments; thick stripes and type-II interstripes, which are strongly orientation selective and thin stripes and type-I interstripes, which are significantly less selective for orientation and exhibit larger orientation gradient magnitudes.
传统上认为，猕猴的V2区由3个不同的功能区组成，这些功能区具有独特的皮质连接和功能特性。方向选择性是一种经常被用来区分V2区条纹的特性，然而，在V2区各功能区的高比例神经元中都发现了这种感受野特性。我们使用定量内在皮质成像技术，得出了V2区细条纹、粗条纹和条纹间区域的首选方向、方向选择性和方向梯度图谱。在每个V2区条纹中都发现了方向选择性反应，但不同条纹之间方向选择性的大小和组织存在显著差异。值得注意的是，每条细胞色素氧化酶密集条纹两侧的两条淡条纹在方向表征上存在显著差异，因此被区分为I型和II型条纹间区域。V2区方向图谱的特征是顺时针和逆时针方向的“方向风车”，但与V1区不同，它们在V2区的分布并不均匀。此外，V2区条纹包含大规模的首选方向序列。这些分析表明，V2区由4个不同的功能区组成：粗条纹和II型条纹间区域，它们具有很强的方向选择性；细条纹和I型条纹间区域，它们对方向的选择性明显较低，且方向梯度幅度较大。
