Ganglion cell circuits in primate fovea

In the standard view all information from the fovea is relayed via only two types of ganglion cell, P (midget) and M (parasol) thought to form respectively 90–95% and 5–10% of the ganglion cell population. We characterized all 157 ganglion cells in a small patch of macaque fovea using electron micrographs of serial sections. One hundred fifteen (73%) were midget ganglion cells and were of two types, one with 28 ± 4 bipolar synapses and the other with 47 ± 3 synapses. Forty-two (27%) were non-midget ganglion cells. Most had dendrites restricted to either sublamina a or sublamina b of the inner plexiform layer, but one quarter had dendrites in both. These cells were of two types, one with input in sublamina b from blue cone bipolar cells and the other with only diffuse bipolar cell input. The ganglion cells with dendrites in either sublamina a or sublamina b were of at least one type with the possibility of more. We conclude that non-midget ganglion cells are numerous and provide additional parallel arrays to brain.

在标准观点中，来自中央凹的所有信息仅通过两种神经节细胞传递，即P（侏儒）细胞和M（伞状）细胞，它们被认为分别占神经节细胞群体的90 - 95%和5 - 10%。我们利用连续切片的电子显微照片对猕猴中央凹的一小块区域内的所有157个神经节细胞进行了特征描述。其中115个（73%）是侏儒神经节细胞，分为两种类型，一种具有28 ± 4个双极突触，另一种具有47 ± 3个突触。42个（27%）是非侏儒神经节细胞。大多数细胞的树突局限于内网状层的a亚层或b亚层，但四分之一的细胞在两个亚层都有树突。这些细胞分为两种类型，一种在b亚层接收来自蓝锥双极细胞的输入，另一种仅接收弥散双极细胞的输入。树突位于a亚层或b亚层的神经节细胞至少有一种类型，也可能有更多类型。我们得出结论，非侏儒神经节细胞数量众多，并为大脑提供了额外的平行排列。