Marrocco R T, McClurkin J W, Young R A
J Neurosci. 1982 Sep;2(9):1275-91. doi: 10.1523/JNEUROSCI.02-09-01275.1982.
Cells in the lateral geniculate nucleus (LGN) of the macaque monkey were investigated with microelectrodes in an attempt to develop an overall classification scheme. We classified cells in the parvocellular (P) and magnocellular (M) layers according to (non)linearity of spatial summation, shock latency, and chromatic organization of center and surround. We also measured the spatial and temporal tuning to counterphasing and drifting sine wave gratings and tested for periphery effects. Our results showed that no strict laminar segregation existed for any cell property studied. Our results can be summarized as follows: 1. Most P layer cells showed a linear summation (98%) and color-opponent responses (80%), while other cells showed a nonlinear summation (Y-cells, 2%) and broad band responses (28%). In contrast, 37% of the M layer cells were linear summators and the remainder were nonlinear. Therefore, there are overlapping distributions of X- and Y-cells in P and M layers but not a strict segregation. 2. P layer cells had longer shock latencies than M layer cells. X-cells conducted more slowly (2.4 +/- 0.7 msec) than Y-cells (1.6 +/- 0.8 msec), but there were overlapping distributions. Latency shortened gradually, rather than abruptly, with increasing depth. 3. The first harmonic of X- and Y-cell responses was maximally sensitive to spatial frequencies of about 2 cycles/deg. Each type of cell modulated about a mean rate to a drifting grating, although Y-cells had higher distortion than X-cells. Response amplitudes to drifting gratings were higher for MX- and MY- than for PX-cells. No DC elevation to high spatial frequencies was seen. Spatial bandwidths averaged 2 to 5 octaves. X-cells were maximally tuned to temporal frequencies around 11 Hz, and Y-cells were tuned to about 19 Hz;. temporal bandwidths for both averaged 2.8 octaves. 4. Periphery effects were detected in 4% of the X-cells and 25% of the Y-cells. 5. These data indicate that gradual changes occur between dorsal and ventral layers: summation changes from linear to nonlinear; conduction latencies shorten; peak temporal tuning increases; response amplitudes increase; the periphery effect becomes more prevalent. Spatial tuning does not change. No strict laminar segregation or specificity exists for any of the properties that we studied.
为了建立一个全面的分类方案，研究人员用微电极对猕猴外侧膝状核（LGN）中的细胞进行了研究。我们根据空间总和的（非）线性、电击潜伏期以及中央和外周的颜色组织，对小细胞（P）层和大细胞（M）层中的细胞进行了分类。我们还测量了对反相和漂移正弦波光栅的空间和时间调谐，并测试了外周效应。我们的结果表明，对于所研究的任何细胞特性，都不存在严格的分层隔离。我们的结果可总结如下：1. 大多数P层细胞表现出线性总和（98%）和颜色拮抗反应（80%），而其他细胞表现出非线性总和（Y细胞，2%）和宽带反应（28%）。相比之下，37%的M层细胞是线性总和器，其余是非线性的。因此，P层和M层中X细胞和Y细胞存在重叠分布，但并非严格隔离。2. P层细胞的电击潜伏期比M层细胞长。X细胞的传导速度比Y细胞慢（2.4±0.7毫秒）（Y细胞为1.6±0.8毫秒），但存在重叠分布。随着深度增加，潜伏期逐渐缩短，而非突然缩短。3. X细胞和Y细胞反应的一次谐波对约2周/度的空间频率最为敏感。每种类型的细胞对漂移光栅的调制速率约为平均值，尽管Y细胞的失真比X细胞高。MX细胞和MY细胞对漂移光栅的反应幅度高于PX细胞。未观察到对高空间频率的直流升高。空间带宽平均为2至5个八度。X细胞对约11赫兹的时间频率调谐最佳，Y细胞对约19赫兹调谐最佳；两者的时间带宽平均为2.8个八度。4. 在4%的X细胞和25%的Y细胞中检测到外周效应。5. 这些数据表明，背侧层和腹侧层之间发生了逐渐变化：总和从线性变为非线性；传导潜伏期缩短；峰值时间调谐增加；反应幅度增加；外周效应变得更加普遍。空间调谐不变。对于我们研究的任何特性，都不存在严格的分层隔离或特异性。
