Which LGN layers serve the smallest receptive fields?

Table 2

	Direction selectivity (DI)	Receptive field width (minarc)
4B	0.15	15
	(7)	(7)
4Cα	0.14	30
	(13)	(13)

How is the LGN organized?

The LGN consists of six eye-specific layers, four of which receive inputs from parvocellular retinal ganglion cells, and two of which receive magnocellular inputs. Each layer is organized into a precise retinotopic map.

Which V1 layer receives the most input from the LGN?

Area V1 contains a complete map of the visual field covered by the eyes. It receives its main visual input from the lateral geniculate nucleus of the thalamus (LGN), and sends its main output to subsequent cortical visual areas (Maunsell and Newsome, 1987; Van Essen and Felleman, 1991).

How is the lateral geniculate nucleus organized?

The Lateral Geniculate Nucleus is a part of the thalamic sensory relay system. This nucleus is organized in six layers, shaped to look very much like a finger print. The receptive fields of cells in the LGN exhibit the same concentric on-off characteristics as those of retinal ganglion cells.

What are LGN cells?

Anatomical terms of neuroanatomy The lateral geniculate nucleus (LGN; also called the lateral geniculate body or lateral geniculate complex) is a relay center in the thalamus for the visual pathway. It is a small, ovoid, ventral projection of the thalamus where the thalamus connects with the optic nerve.

What are the layers of the LGN?

The LGN has:

• 6 layers.
• Cells have monocular input.
• Layers alternate inputs from each of the two eyes.
• The top four are parvocellular layers, two layers from each eye. Parvo (small) LGN cells receive inputs from (small) midget ganglion cells.
• The bottom two are magnocellular layers, one layer from each eye.

How many layers are there in the LGN?

role in vision The LGN in humans contain six layers of cells. Two of these layers contain large cells (the magnocellular [M] layers), and the remaining four layers contain small cells (the parvocellular [P] layers). This division reflects a difference in the types of ganglion cells that supply the…

What are the six layers of the LGN?

M, P, K cells The magnocellular, parvocellular, and koniocellular layers of the LGN correspond with the similarly named types of retinal ganglion cells.

Which type of retinal cells project to the lower two layers of the LGN in the thalamus?

parasol cells
The upper two layers become interleaved to form four layers, two each per eye. In primates, three or more anatomical classes of ganglion cells innervate the LGN. The parasol cells of the retina project to the lower two large cell containing layers, known as the magnocellular layers of the LGN.

What do Koniocellular layers do?

The koniocellular cells receive their input from bistratified retinal ganglion cells exiting the optic tract, and send their information via relay neurons in the optic radiation to the primary visual cortex.

What cells are in the LGN?

The basis of the structure of the lateral geniculate nucleus is mostly in terms of its three distinct cell types: magnocellular (M), parvocellular (P), and koniocellular (K).

What lobe is the LGN in?

The LGN neurons (4° visual afferents) send their axons in the internal capsule to the occipital lobe where they terminate in the striate cortex (Figure 15.5).

What is the difference between LGN and LGN cells?

Layers alternate inputs from each of the two eyes. The top four are parvocellular layers, two layers from each eye. Parvo (small) LGN cells receive inputs from (small) midget ganglion cells. The bottom two are magnocellular layers, one layer from each eye. Magno (large) LGN cells receive inputs from (large) parasol ganglion cells.

How many layers are there in the human LGN?

All primates have at least two P and two M layers with K layers lying below each M and P layer. In humans and some other primates, each P layer can split into two or more layers in the portion of the LGN that represents central vision (∼2–17 degrees). The normal human LGN can contain as few as two or as many as six P layers.

Which retinal ganglion cells are known to project to the LGN?

The midget (red circle) and parasol (gray) cells are known to project to the P and M layers, respectively. The small bistratified cells (blue) are known to project to the K layers. Several other types of retinal ganglion cells (yellow) are also known to project to the LGN, but the layer specificity of their projection is currently unknown.

What is the structure of the lateral geniculate nucleus?

Structure. Both the left and right hemisphere of the brain have a lateral geniculate nucleus, named after its resemblance to a bent knee ( genu is Latin for “knee”). In humans as well as in many other primates, the LGN has layers of magnocellular cells and parvocellular cells that are interleaved with layers of koniocellular cells.