Question

Explain how light reflecting off from an object in the world gets from the outside world and into your conscious thoughts, in other words, describe the structures that the visual stimuli/signal must go through to reach perception

Answer 1

Visual perception is the ablity to perceive our surroundings through the light that enters our eyes, visual perception occurs on the brains cerebral cortex, the electric signals get there travelling through optic nerve and the thalamus, the process can take place in a mere 13 milliseconds.

Visual pathway begins when light rays passing through cornea and centering at fovea and back of retina, the first cell in the pathway is the photoreceptor which converts light energy into neuronal signal, this signal is passed on to the bipolar cells and amacrine cell and then to the ganglion cell, all these cells and synapses lie within the retina, the axons of the ganglion cell exit the retina through optic nerve, the optic nerve from both eyes meet and cross the optic chiasma, at this point, information of both eye is combined and than split according to the visual feild, the right and left are sent to the left and right halves of the brain to be processed, the information from right visual feild (left side of brain) travel to left optic tract and vice versa, each optic tract terminate in the lateral genicualt nucleus (LGN) which is the sensory relay nucleus in the thalamus of the brain, the fibers leave the LGN as optic radiation, the optic radiation one on each side of the brain carry information from the thalamic lateral genuiculate nucleus to the layer of visual cortex, the visual pathway is separated into ventral and dorsal pathway the visual cortex is responsible for perceiving the visual image.