Heading encoding in the macaque ventral intraparietal area (VIP)
Heading encoding in the macaque ventral intraparietal area (VIP)
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DOI：
10.1046/j.1460-9568.2002.02207.x
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发表时间：
2002-10-01
影响因子：
3.4
通讯作者：
Graf, W
中科院分区：
文献类型：
--
作者：
Bremmer, F;Duhamel, JR;Graf, W
我们记录了两只清醒猕猴腹侧顶内区（VIP）的神经元对光流刺激的反应。根据之前对猴子纹外皮层视流反应的研究，我们使用了不同的刺激类别：额平行运动、径向刺激（扩张和收缩）和旋转刺激（顺时针和逆时针）。百分之七十五的细胞对一种或多种光流刺激表现出统计上显着的反应。在几乎所有情况下，改变视场内光流刺激奇点的位置都会导致响应调制。对于大多数神经元来说，这种调节影响可以通过二维线性回归以统计上显着的方式来近似。从回归参数导出并指示响应增加最陡的方向的梯度方向是均匀分布的。在人群水平上，观察到对不同焦点位置的刺激的无偏平均反应。通过应用称为“等频编码”的群体代码，我们证明了记录的神经元集合从其群体放电中检索焦点位置的能力。对扩张和收缩刺激的反应无法根据神经元额平行首选刺激方向及其感受野的位置和大小的定量数据来预测。这些结果与该区域的多模态运动响应数据一起表明 VIP 区域参与了航向的分析和编码。
We recorded neuronal responses to optic flow stimuli in the ventral intraparietal area (VIP) of two awake macaque monkeys. According to previous studies on optic flow responses in monkey extrastriate cortex we used different stimulus classes: frontoparallel motion, radial stimuli (expansion and contraction) and rotational stimuli (clockwise and counter-clockwise). Seventy-five percent of the cells showed statistically significant responses to one or more of these optic flow stimuli. Shifting the location of the singularity of the optic flow stimuli within the visual field led to a response modulation in almost all cases. For the majority of neurons, this modulatory influence could be approximated in a statistically significant manner by a two-dimensional linear regression. Gradient directions, derived from the regression parameters and indicating the direction of the steepest increase in the responses, were uniformly distributed. At the population level, an unbiased average response for the stimuli with different focus locations was observed. By applying a population code, termed 'isofrequency encoding', we demonstrate the capability of the recorded neuronal ensemble to retrieve the focus location from its population discharge. Responses to expansion and contraction stimuli cannot be predicted based on quantitative data on a neuron's frontoparallel preferred stimulus direction and the location and size of its receptive field. These results, taken together with data on polymodal motion responses in this area, suggest an involvement of area VIP in the analysis and the encoding of heading.