In: Anatomy and Physiology
How are visual inputs organized in the LGN and in V1? And how do the visual field of photoreceptors (dots of light) result in the edges/lines for the visual cortex?
Visual inputs in Lateral geniculate Nucleus (LGN):
The LGN has:
1.It has 6 layers and cells has monocular input.
2.Layers has alternate inputs from each of two eyes.
3.Top four has has parvocelluar layers. two layers from each eye.
4. LGN cells receive inputs from midget ganglion cells.
5. Bottom two are magnocellular layer,one layer from each aye.
6. magno LGN cells receive input from parasol ganglion cells.
V1 inputs:
Visual cortex is subdivided into number of seperate and distinct regions called visual cortical area.V1 is located in calcarin sulcus in medial occiptal lobe of brain and back of the head.V1 is primary because LGN sends most of axons to there so v1 is first procesding area in the cortex.
Visual field:
Visual field is that area in the space perceived when eyes are in when eyes are in fixed,static position looking straight ahead.
Monocular visual field: Is that area of space visible to one eye.it can be mapped parametrically.perimetry testing provides the details of visual field.the potential visul field describe as a hemisphere.However it does not formed the perfect hemisphere as the brow, nose and cheekbones obscure the view.