MOTION SELECTIVITY IN MACAQUE VISUAL-CORTEX .2. SPATIOTEMPORAL RANGE OF DIRECTIONAL INTERACTIONS IN MT AND V1
MOTION SELECTIVITY IN MACAQUE VISUAL-CORTEX .2. SPATIOTEMPORAL RANGE OF DIRECTIONAL INTERACTIONS IN MT AND V1
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DOI：
10.1152/jn.1986.55.6.1328
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发表时间：
1986-06-01
影响因子：
2.5
通讯作者：
WURTZ, RH
中科院分区：
文献类型：
--
作者：
MIKAMI, A;NEWSOME, WT;WURTZ, RH
我们测量了105个定向选择性中颞叶（MT）神经元和26个定向选择性纹状体（V1）神经元的定向相互作用的空间和时间限制。使用连续闪烁的刺激，其中刺激之间的空间和时间间隔系统地在很宽的范围内变化的方向相互作用进行了测量。一个方向指数，以确定强度的方向相互作用的空间和时间间隔测试的每一个组合。特定神经元中发生定向相互作用的最大空间间隔与MT和V1的感受野大小和视网膜偏心率正相关。平均而言，MT的最大空间间隔是V1的三倍。最大的时间间隔，我们得到的定向相互作用是类似的MT和V1，并没有随着接收场的大小或偏心率。闪光刺激测量的方向性相互作用的最大空间间隔与产生方向性反应的平滑运动的最大速度呈正相关。MT神经元比V1神经元定向选择性更高的速度。这些观察结果表明，在MT中发现的大的感受野允许在更长的距离比更有限的V1神经元的感受野定向相互作用。因此，MT神经元具有功能优势，因为它们比V1神经元检测到更高速度的方向差异。最近的心理物理学研究测量了空间和时间的限制知觉的明显的运动在顺序闪烁的视觉显示。我们的生理数据的心理物理结果的比较表明，感知的时空限制是类似的MT神经元的方向选择性的限制，但明显不同于V1神经元。这些观察结果表明，MT的神经元反应和短距离的明显运动过程之间的对应关系。
We measured the spatial and temporal limits of directional interactions for 105 directionally selective middle temporal (MT) neurons and 26 directionally selective striate (V1) neurons. Directional interactions were measured using sequentially flashed stimuli in which the spatial and temporal intervals between stimuli were systematically varied over a broad range. A direction index was employed to determine the strength of directional interactions for each combination of spatial and temporal intervals tested. The maximum spatial interval for which directional interactions occurred in a particular neuron was positively correlated with receptive-field size and with retinal eccentricity in both MT and V1. The maximum spatial interval was, on average, three times as large in MT as in V1. The maximum temporal interval for which we obtained directional interactions was similar in MT and V1 and did not vary with receptive-field size or eccentricity. The maximum spatial interval for directional interactions as measured with flashed stimuli was positively correlated with the maximum speed of smooth motion that yielded directional responses. MT neurons were directionally selective for higher speeds than were V1 neurons. These observations indicate that the large receptive fields found in MT permit directional interactions over longer distances than do the more limited receptive fields of V1 neurons. A functional advantage is thereby conferred on MT neurons because they detect directional differences for higher speeds than do V1 neurons. Recent psychophysical studies have measured the spatial and temporal limits for the perception of apparent motion in sequentially flashed visual displays. A comparison of the psychophysical results with our physiological data indicates that the spatiotemporal limits for perception are similar to the limits for direction selectivity in MT neurons but differ markedly from those for V1 neurons. These observations suggest a correspondence between neuronal responses in MT and the short-range process of apparent motion.