Which cells project to LGN layers 1-2?

Which cells project to LGN layers 1-2?

• A. P cells
• B. M cells
• C. Koniocellular cells
• D. Rod cells

Answer: (B)

Layers 1 and 2 of the LGN are the magnocellular layers, which receive input from the M-type retinal ganglion cells. These cells are large and have big receptive fields, making them fast responders to luminance changes and motion with high temporal resolution. That fast, transient signal is precisely what the magnocellular pathway is built to carry into the LGN and onward to the visual cortex. In contrast, the parvocellular cells populate the other LGN layers (3–6) and are tuned for high spatial detail and color, while koniocellular pathways occupy intercalated layers between the main ones. Rods don’t project directly to specific LGN layers as a separate channel; their signals are carried into the LGN via the same ganglion-cell pathways (M or P) depending on the network, but not as a distinct direct projection to layers 1-2. So the cells projecting to LGN layers 1-2 are the magnocellular M cells.

Layers 1 and 2 of the LGN are the magnocellular layers, which receive input from the M-type retinal ganglion cells. These cells are large and have big receptive fields, making them fast responders to luminance changes and motion with high temporal resolution. That fast, transient signal is precisely what the magnocellular pathway is built to carry into the LGN and onward to the visual cortex. In contrast, the parvocellular cells populate the other LGN layers (3–6) and are tuned for high spatial detail and color, while koniocellular pathways occupy intercalated layers between the main ones. Rods don’t project directly to specific LGN layers as a separate channel; their signals are carried into the LGN via the same ganglion-cell pathways (M or P) depending on the network, but not as a distinct direct projection to layers 1-2. So the cells projecting to LGN layers 1-2 are the magnocellular M cells.